David Weitz

Zierler:

This is David Zierler, oral historian for the American Institute of Physics. It is June 25th, 2020. It is my great pleasure to be here with Professor David Weitz. Dave, thank you so much for being with me today.

Weitz:

My pleasure.

Zierler:

OK, so to start would you please tell me your title and institutional affiliation.

Weitz:

I'm a professor of physics and applied physics. I work at Harvard University. I'm in the physics department and jointly in the School of Engineering and Applied Sciences.

Zierler:

OK, great. And now let's take it right back to the beginning. Tell me a little bit about your family background. Where are your parents from?

Weitz:

My parents were in Canada. My father, I think, was born en route to Canada from Russia. So, my grandparents are Ukrainian. My parents are Canadian. I was born and raised in Canada. I'm still a Canadian citizen, but I'm also now a joint US citizen. And I have spent probably two thirds of my life in the US.

Zierler:

What were your parents’ professions?

Weitz:

So my father was an economist, not a Ph.D. He was a master's level economist who worked on the Canadian equivalent of Social Security in Canada and helped develop, helped bring that in, worked for the government. My mother was a housewife at the time, but she divorced my father soon after I was born and she went on to have a career of sort of an entrepreneur, building houses, investing in land, doing small business through all of her life.

Zierler:

What household did you grow up in?

Weitz:

Mainly my father’s.

Zierler:

Did you keep a relationship with your mother?

Weitz:

Yes, I did.

Zierler:

And where did you grow up? Where in Canada?

Weitz:

In Ottawa.

Zierler:

Did you go to a public school there?

Weitz:

Yep, no sorry. Sorry. I should not say that. I went to public school for high school and I went to a private school for, what do you call it, grade school because I went to a school that also taught Hebrew, something both the Jewish religion –

Zierler:

Oh, OK. Your family was Jewishly connected growing up?

Weitz:

[Laughs] No, it was again, more for reasons having to do with a big disagreement between my parents about their children and the desire of my father to change his value to us by being religious in the courts. The divorce was a very nasty thing. I have grown and it doesn't bother me anymore, but it's an amazing story that you don't want to hear. It doesn't involve me and all the other people.

And so my religion was brought to me because of court cases. So I became, well, not really, I learned about religion, certainly. To me it is religion that's practicing religion and there's culture. And the culture part has always been part of me. But the religious part was something that I was educated in.

I remember after my bar mitzvah; I remember eating a piece of pizza that had pepperoni on it. And I said, man, I'm eating milk with meat and I'm eating pork. This is so good. Screw this religious business. I'm just going to eat what I want. That's how I became more secular on the religious type but still of course a Jew.

Zierler:

So I take it you are happy to go to public school when you are older for high school?

Weitz:

No, no, no. No, the private school was spectacular. You know, you had to learn twice as much, right. You had to learn Hebrew and culture and English. And so they had just spectacular teachers. And so you learn how to learn. You learn how to be serious about learning. It was probably the best experience I could imagine. So, no, I was very happy to go there. Public school was OK, but I think I learned about learning about the joy of learning things in private school.

Zierler:

Kosher issues excepted, was there a part of you that wished you stayed in the Jewish educational system?

Weitz:

No, I don't have regrets about anything. I was happy to do it. I'm happy not to do it. I have very few things in life that I regret. So I don't regret that.

Zierler:

I'm sure one part, one piece of the public school education was the science. I'm sure you had a strong science education in high school.

Weitz:

Again, let me just think, it was not something that I... I don't have memories of learning about science in school, I have to say. Not in high school. I imagine I did. It's not something I remember. I remember being really interested in what you would call mathematics. I was really more into numbers, the beauty of numbers. It's always fascinating. I've always been curious, but not really being overly fascinated with science, per say, I think, in high school. There are too many other things I was interested in.

Zierler:

[Laughs] Were you good in math and science in high school?

Weitz:

Again, I don't have any recollection of being particularly good or bad.

Zierler:

When you were thinking about college programs, so I take it you were not thinking specifically about majoring in science at that point?

Weitz:

Well, it's very interesting. So I debated, debated, debated. I was thinking where I should go and for other, again, unrelated family reasons, I did not go to university in Ottawa. I didn't want to go to university in Toronto where the best universities were. So instead, I went to this university in Waterloo and there they had faculty of mathematics and their strength was mathematics and computers. And at this day and age, computer science was really nascent, shouldn't really exist.

Zierler:

What year did you enter college?

Weitz:

When did I go to college? 1969. So it was really early days. You didn't have calculators. We had a computer that was in an enormous room. Was one of these old IBM computers 370s or something, I forget what they're called. That you know, barely did what a programable calculator did many years later. So it's really early days. But I thought it sounded interesting, I didn't know anything about it. And so I was going to become a computer scientist. That's how I went. No real reason. Just seemed like something I should do.

Zierler:

I'm curious. You entered college in 1969. Had the counterculture reached Waterloo? Was that a part of the scene there?

Weitz:

Well, that's the thing that, you know, it was a real protest time in the US.

Zierler:

Right.

Weitz:

And we knew about it through the news. But also, we were inundated with draft dodgers. And those were the days of the draft. Those are the days where, if you were drafted, you had a good chance of not surviving. So it was amazing time in the US, which I didn't live through, I just lived as somebody in a neighboring country, fairly young at the time. But a lot of Americans were in Waterloo because they didn't want to be in the US.

Zierler:

Did you think computer science throughout your undergraduate education?

Weitz:

Well, an interesting thing happened that a physics professor, a real character, came to me one day and says, oh, by the way, do you remember that in high school you took this exam that was given by the University of Waterloo? It's called the Sir Isaac Newton exam.

He said, “Do you remember you took it?” I said, “Well, yeah, I took it. I didn't do that well.” He said, “No, you didn't do that well, but you did well enough, you didn't win one of the prizes, but you did well enough that if you just say that you're a physics major, not a computer science major, you will take exactly the same courses. Exactly, do exactly, everything will be the same. But just say you're a physics major. I'm going to give you five hundred dollars that would pay your tuition.” I said, “Well my father's paying my tuition, so I'd be happy if he doesn't have to pay.” So I said, “Sure, why not?” It sounded like a good deal.

So I said, OK, I'm a physics major and I studied computer science. And then second year he came to me. So I said, “I see you're here again.” He said, yeah, if you do it again, the courses are exactly the same. Really. Take science courses. Take whatever courses you want but just call yourself a physics major. I'm going to give you five hundred dollars again. Seemed like a good deal, so I did it. And the third year I saw him, he started coming, I told him, you know what? I like physics. I think I'll be a physics major anyways. He still gave me the five hundred dollars. So I always say that I was bought to come to physics for five hundred bucks a year.

Zierler:

[Laughs] Did you have any idea what his motivation was to support you in this way?

Weitz:

Yeah, sure. Because, you know, it's like always when you're a lower ranked department, you're a good department, but you don't have the flash, the pizzazz, the size and the influence of a big department like computer science. You do what you can to try and get people to be majors in your department. So they were just trying to get more majors. And I'm sure I was not the only. They offered this to several people. Just a way to get people.

Zierler:

And was there any particular course that captivated you, that made you switch over officially?

Weitz:

Just it seemed much more rigorous, much more interesting. Much more dealing with the world around me with reality, with things like that. Whereas, computer science in those days, I don't think, I never could figure out what it really was. It didn't seem so much like a science at the time. So it just it didn't appeal to me. It wasn't as much science that was tangible that you could touch, to me, as the courses that I took. Whereas physics was very real.

Zierler:

Did you get exposed fairly broadly to most areas of physics theory and experimentation both?

Weitz:

The experiments were boring because they were lab experiments. You know, canned lab experiments that were not interesting. The concept and theory work were very, very rigorous. So I took lots of courses, probably more courses than I would have taken in an American university, and that was good.

And then in Canada, you have these very long summer vacations by comparison to the US. And it's a tradition that you go and work somewhere. So I spent a couple of summers working in research labs. And that's what convinced me to become a scientist.

Zierler:

Oh wow. What research labs were most foundational for you?

Weitz:

Well, for me, I spent the summer at the Weizmann Institute. But that was just more fun. I didn't really learn that much science. But then I spent the summer...

Zierler:

Did you get to use your Hebrew?

Weitz:

Oh, yeah. Yeah, absolutely. Yeah, it still was an English language program, but I could speak enough Hebrew to get along pretty well in those days. But the next year in Ottawa, there was this government research lab, it is like a national lab here. But in those days, it was an extremely powerful lab. In fact, Hertzberg was there who won the Nobel Prize for his work that he did there.

And so there's a big group on spectroscopy and I worked in some guy's lab. You know, I just really liked it. I mean, this is all hands on, it was all just using my hands, thinking with my hands as much as with my head. Really doing experiments, which is what I enjoyed. I just thought that was fantastic. And then I did that again the next summer, but by then I was actually hooked to try and do experiments of some sort.

Zierler:

What kinds of experiments did you enjoy the most?

Weitz:

Well, these are all what you would call condensed matter now. They weren't at the time. Well, one year was for optics, I think we were using CO2 lasers to do some spectroscopy, but it still meant that there were really hands-on experiments.

The other year was doing organic semiconductors, organic insulators, layered organic materials, and it was just doing experiments of measuring conductivity. But, you know, with these samples you had to learn how to make leads, how to make connections. It was a mixture of chemistry and physics, mechanics, everything. So it was doing what you would now call condensed matter physics, or what I would now call condensed matter physics. I'm not even sure was called that back in those days.

Zierler:

Solid-state. Was that a term that was used?

Weitz:

Solid-state was a big term, but that was not what we were doing. That's why we call it condensed matter. So solid-state was really the state of the art of condensed matter because there was so much going on in solid-state, and that was a real area of expertise at Waterloo.

There were a lot of people who did solid-state work, and really, I would distinguish solid-state from condensed matter physics because I think condensed matter physics grew enormously when it broadened itself out beyond solid-state. In those days, I think it was a whole field of condensed matter physics was essentially all solid-state physics because of the importance of the early stages of the development. But I think that it became maybe narrowly focused on that and it expanded, and to me that may have added to the richness. But you had to search that out on that expansion, at least in a place like Waterloo.

Zierler:

When you graduated from college, what were your ambitions at that point? What did you want to do next?

Weitz:

So, you know, I'll tell you what happened. This was Canada, as you know. It is a small economy, very susceptible to ups and downs. And this was a downtime in the economy. And I went home and I read in the newspaper, you know, the economic situation was so bad that in Ottawa even Ph.D. physicists were driving taxi cabs. And so I said, gee, if I want to get a job, I better get a Ph.D. in physics so I can drive a taxi.

Zierler:

[Laughs]

Weitz:

And, you know, there weren't any jobs. You had no options. So you couldn't find a job very easily when you graduated college. So it seemed like a good thing to do to go to grad school.

Zierler:

That would shield you from the job market for a couple of years?

Weitz:

Exactly. Exactly. And then I started asking, I said, OK, I guess I have to go to graduate school because I'm not going to find a job doing anything else. And all my professors said, well, if you're really serious, if you're serious about doing graduate school and you're a Canadian, you got to go to the US to do it. Can't go to Canada, gotta go to the U.S.

Zierler:

This included even McGill and McMaster and University of Toronto? They don't fit the bill?

Weitz:

You know, again, thinking of the times. We were in the peak of the, just ending the draft dodging days. A lot of the professors, a lot of the teaching fellows, the postdocs were all American. Most of the professors in Waterloo, many of them were Canadians who came from the US, who studied in the US. And so that was the advice I was being given. They said, yeah, you could go to the big schools, Toronto or UBC. But they said if you're really serious, you better go to the US.

Zierler:

What schools did you apply to?

Weitz:

I applied to a bunch, but I can remember I applied to University of Illinois in Champaign Urbana.

Zierler:

Sure.

Weitz:

And I applied to M.I.T. and applied to Harvard. I think I applied to Berkeley also because I always thought that would be a very cool place to go, given the cultural revolution that was happening.

I think I wasn't accepted at Berkeley. At M.I.T., I was accepted, but they weren't going to give me a stipend. They didn't tell me they'd give a stipend, so it didn't seem worthwhile. I was accepted maybe a bunch of other places. Penn, I was accepted there, I was accepted to Harvard. I was accepted to UIUC.

And the reason I applied there was that all my professors, most of them in condensed matter, were solid-state physicists, had gone and had studied there because that was the era when Bardeen was there, Schrieffer. It was the heyday of solid-state physics and Illinois was just a spectacular place. And all my professors told me, you got to go to Illinois, it's the best place in the world, it's a really great place. They told me the great thing about Illinois is your professors will talk to you, not like a place like Harvard. Your professors will never talk to you at Harvard.

And so I was all set to go, ready, fine, ready to go. I went to talk to one more professor. He was a European, did NMR, not really condensed matter. Well, he did condensed matter but not solid-state, did NMR. And he looked at me, said how is this a good choice, tell me. In the afternoons, in the evenings, what would you rather do? Watch the corn grow or listen to the Boston Symphony?

Zierler:

[Laughs] Ouch.

Weitz:

I said, you know, you're right. So I changed. I decided I better go to Harvard.

Zierler:

Would you be willing to share the name of this professor who gave you this advice?

Weitz:

I don't remember. I'm sorry. I could look it up. I want to say, Gruner, but I don't think was, it was something like that. He was a, you know, you just have to look up who was a professor at the University of Waterloo in 1972/73, that era, who did NMR. He was maybe Hungarian or something like that. People were very friendly at Waterloo. You could walk in and talk to people. It was no problem.

Zierler:

So that was it for you? Cambridge here you come.

Weitz:

Cambridge here I came. I never regretted it, but that's what I did.

Zierler:

Did you find that the reputation that professors wouldn't talk to you at Harvard, did you find that that was accurate in your experience?

Weitz:

Let me say that as a professor at Harvard now, I understand the problems as much as I worked very, very hard to avoid it. But still, it is a problem. And yes, but not in a detrimental way. But, yes, it's hard to talk to professors because everybody is so busy and there's so many opportunities in what goes on around Cambridge, what goes on around Harvard and the whole environment, that everybody is very, very busy. And so, yeah, it's harder to find time to talk to people. It's harder for students to find time to talk to professors.

So, yeah, that's a problem. It never affected me. I didn't bother me. I gained enormous insight, value and information from students, postdocs. You were just surrounded by such excellence that you learn from everybody, you learn from the environment.

Zierler:

What year did you enter Harvard?

Weitz:

Seventy-three [1973].

Zierler:

Seventy-three. Okay. And were there particular professors that you were looking to work with or you wanted to keep an open mind until you got to the department?

Weitz:

You know, I didn't know what I wanted to. I had no idea.

Zierler:

But you knew you wanted to focus on solid-state? That much you knew?

Weitz:

No, no, no, no. Not at all. Because while this expertise in solid-state was at Waterloo, I didn't work in any professor's lab at Waterloo. I did lab work and I worked in the summertime, but I didn't work in anybody's lab. It was all my professors told me, oh, solid-state, that's the future. Okay, so I didn't know any better.

And I think it was a tough year for Harvard because, you know, University of Waterloo is a sort of small, not first-rate university in Canada, far from the US, but they accepted two people from Waterloo that year. So the class is 20, 25 people, two of us from the same university. And we both decided to go. So then I just attribute that to them having a tough year. That must have been a lot of competition and not many students. I don't know why they would accept two people from Waterloo. We both went.

And in those days, the way Harvard did it was they assigned everybody an advisor, even though we had nothing to do with the advisor. And I think the advisor probably paid for the student the first year, even though you weren't obligated to work with the advisor or anything. It's just the way that they had this support system to work. Everyone would take one or two students and they would either be their advisor and then we'd find an advisor out of anybody in the department.

And so they assigned me to a guy named, I think his name is Frank Pipkin. And so my friend, the other guy from Waterloo, visited Harvard earlier. Or maybe we visited together, I don't know. I don't think it matters. We visited and he somehow really liked the Pipkin group. He told the department he'd like to work for Pipkin, would it be OK? They said, oh we can do that, we'll just switch you and Dave around. So he had been assigned to work with Mike Tinkham, and I'd been assigned to Frank Pipkin. So they switched us and we went that way. And in fact, we each stayed with the same person. So I was just randomly assigned to Mike Tinkham and I just stayed with his group. It was totally random. I didn't even know who Mike was at the time.

Zierler:

How did you know that you had made the right decision after this random act?

Weitz:

I knew when I graduated that, actually I knew this, in fact, I knew this even at the start. One of the things that everybody said, when you talk to students is, oh, well, now Tinkham is good because his students always get jobs. So that sounds good. I came here because I couldn’t get a job. I said maybe I don't have to drive a taxi. So it seemed like the right thing. But then, you know, in retrospect, it was good work, it was fun. I can debate about what I did and did not do. But I learned a huge amount, I learned a new science. And again, I have zero regrets, it was a good education.

Zierler:

What was some of the most formative lab work you did during your time at Harvard in terms of developing your own identity as a physicist?

Weitz:

So I learned what to do and what not to do. So I had no idea what to do. I had no idea. So Mike said, well, look, this guy just graduated. He was building a laser, and there's a new way of building a laser. And Mike's expertise was superconductivity, but his real claim to fame, his early claim to fame was doing infrared spectroscopy and superconductivity and identifying that there's an energy gap through infrared absorption. So he knew a lot about infrared and he always had a little bit of effort going on around infrared. And he said why don't you build a laser and that sound like fun because I just loved building things, I loved to put things together. I loved to do things with my hands, do things like that.

And so I started doing that and that was a blast. My God, that was fun. First of all, it was optically pump lasers, I could use to lasers. First thing I did, I'm going to learn how to use the machine shop, I had to learn the machine shop. And I started building little bits and pieces and then I realized that, you know, what took me maybe 10 or 12 hours to build something, you could buy it for a hundred dollars. And so I realized my time had a little value to it. I learned how to machine, which is very good. But I learned how not to machine, if you can buy things.

And I spent roughly four and a half years building equipment. I built this laser, but then I said, oh, somebody's come up with a new way of doing it, so I built a new laser. It was it was really great. It was really a lot of fun. And I just played around and just stayed in the lab doing this. And then I finally collected data for six months. And after that, I said, why did I do that? I spent four and a half years building and six months collecting data. Where is the value in that? And as much fun as it was, I realized that's not the right way for me to do the science. And interestingly, I almost never built equipment anymore. I try and use bought equipment and jerry-rigged equipment, but I try not to spend a lot of time building it.

Zierler:

Sounds like you had a pretty hands-off adviser for this very wisdom to come to you, yourself. [Laughs]

Weitz:

Yeah. Yeah. Very hands off.

Zierler:

Did this experiment ultimately inform your dissertation?

Weitz:

I used it. Again, my dissertation, so my dissertation was on the Josephson effect.

Zierler:

Yeah.

Weitz:

Which had been discovered a few years before. It was still before a lot of things were known. And I thought it was a good thing to combine these things. And so I did things and we discovered a bunch of things. And I would hear my advisor give talks and he would put it in this enormous historical perspective and it sounded so great. But I looked at myself and I said I spent five years doing something and is it really important? Have I really done something that's really important? And I could not see why it was so important. I did not think that it had that much of an impact. And after that I realized...

Zierler:

That begs the question, David, begs the question though, many people don't have that expectation for a dissertation, right?

Weitz:

You don't realize, but you don't question it. This I realized after the fact, after I graduated, right? I didn't realize that it was important when I started. Nobody told me that this is important. Nobody said, why are you doing what you do? Nobody ever asked me that. I never asked myself that. Nobody else did. And I decided when I graduated that I want to do things, if I'm going to do a thing and spend a certain amount of time working, I find anything interesting. I can find interesting things in anything I do.

I had such a great time doing my thesis. It was fabulous. I really enjoyed it. You know, I worked really long hours. I loved it, but I could do the same for anything. And I realized, you know, you can work on anything. Why don't you work on something that people care about? And my experience was because I think I didn't do that as a thesis. Nobody asked me that, but then I started asking myself.

Zierler:

Was your sense that pushing the boundaries of the Josephson effect was not something that people cared about?

Weitz:

My sense was I didn't know why I was doing it. I didn't understand that I was going to push the boundaries. I don't think I pushed that hard. I think I added incremental value. I don't think, you know, if we added value, we didn't understand what value it had at the time, we're just doing it because we could do it.

Now I try and teach my students, I always tell them there's two ways of thinking about science. You can do what you can do. You can do those experiments that you know how to do or you can do those experiments that you should do. And our goal should always be to ask which of the experiments that we should do, not what are the experiments that we can do. And I think I, as a graduate student, I did the experiments that I could do.

I had a laser and I said, “What can I do with it?” Oh, the Josephson effect. Maybe if I put a Josephson junction in front of this, I'll see something. And I did. But, you know, that's something I can do. That isn't something I should do. I didn't ask that question. So now I really try and get everybody in my group to ask the question, what are the things we should do? And, you know, I tell them, chances are if I say this, nine times out of ten, I'll be wrong. But I'll learn a lot in being wrong.

Zierler:

Right.

Weitz:

I'm not afraid to be wrong. But, the times that you're right, then you really have something.

Zierler:

So it sounds almost like by your own sacrifice, you really gained a tremendous amount of insight in terms of the things that you can pass on to your graduate students.

Weitz:

Well, I don't see it as a sacrifice. I had a great time. I learned and life is learning. I always tell my students the day I stop learning is the day I'm going to retire. I always want to learn. And so I learned. And so it's not a sacrifice in any way, shape, or form. It was a fabulous experience, and I learned a lot. It just informs the way that I think. Everything should inform you ultimately. It informs you on how you want to do the science that you want to do. And that's how it informed me.

Zierler:

When you finished your graduate work, you know, foreshadowing ahead to Exxon, were you specifically thinking about industry? Did you specifically not want to enter into a faculty position straight out of graduate school?

Weitz:

Well, for a long time, I had no idea. I had no idea what I wanted to do. And then it almost hit me one day because in those days at Harvard, it worked differently. Every senior professor had a junior professor who worked with him, and that junior professor did very well, but never got tenure because they couldn't establish their own reputation. And so Mike was the same, and he had one guy who was a postdoc there. He was a junior professor there when I arrived. His name is Mack Beasley. He left and he went and became very famous at Stanford, so did very well. He didn't get tenure.

The next person had been a graduate student in the group, the senior graduate student who became a junior professor. He was the one who worked with me on my thesis, so he taught me a lot. He was an extremely talented, very, very kind, and good person. He also didn't get tenure. His name was Bill Skocpol.

But I watched him, I watched him go from somebody I knew as a fellow graduate student in the lab doing experiments like me. And then he became an assistant professor, and he stopped doing experiments because he had to advise people. And it just seemed very boring, seemed a really awful thing. So I said, no, I want to go to industry. And in those days, it was a different era in this country. It's what I call the glory days of corporate research.

Zierler:

Right.

Weitz:

It was a time when Bell Labs existed and was strong, and they supported basic research and other companies looked at them and said, they're so successful we should support basic research. Everybody's building basic research labs. G.E. had basic research, IBM, they all had basic research labs. It was a time you could go and you could do research in industry, and it just seemed the place to do it. So now I decided that's what I wanted to do because I want to actually do research with my hands.

Zierler:

Was Exxon one of those companies that emulated Bell Labs in terms of fostering basic research?

Weitz:

Absolutely. So Exxon started its lab because it saw what Bell Labs did. Saw the power of what they thought was happening. What they didn't understand in those days was the limitations of Bell Labs. They hired somebody who came from Bell Labs, who was an adviser to Reagan. So it was a very powerful scientist as the CEO of a separate company called Exxon Research and Engineering. Basically, he directed the research effort at Exxon and they started this company. Well they it started a number of years earlier, but they told them, please expand and become a basic research company.

And so it was just booming, it was hiring people. I always say that when I was hired, if you had a pulse that was, you know, above 10 beats per minute and you breathed at least twice a minute, they'd hire you, especially if you said you're a physicist, they'd hire you. So they hired anybody. Actually, that's not true. They hired a bunch of young people, and so they really expanded rapidly.

Zierler:

And this was, what? 1978? When you started?

Weitz:

I started in ‘78. I would say their expansion started, the first people there were maybe ‘76, ‘77. They'd been there two, three years. And there were maybe half a dozen physicists at the time and then they hired a couple hundred. And so it was just an amazing place.

Zierler:

And obviously, if they're emulating Bell Labs, there's no concern about you being forced to do research on oil and natural gas.

Weitz:

Not the way you would now. But what was interesting is that we had a bunch of people who were there, one of whom was there only two years, but had enormous impact, his name was Phil Pincus, he's still at Santa Barbara now. He was there only two years, interestingly, but he had an enormous impact. He said, look, if you ask about the sustainability of science, you can't do science, you can't do basic science unless it has some potential impact. And so solid-state physics, which was the main area of work at the time, had impact in Bell Labs. And that's why solid-state physics was so important as a field. It's not just because of the interest, is because of the impact, the potential impact.

So he was right. He's absolutely right. He said, so what's going to impact a company like Exxon? It's going to be fluids, disordered systems, some combination of all sorts of things. We didn't even know what to call it. So we knew there was some kind of interesting condensed matter physics, but we didn't even know what to call it. And we had a conference on this. I didn't organize it but people organized a conference, I think was called macro-molecular science or something like that, I forget. All sorts of things. And one of the key people that we had as consultant we would sometimes just called it de Gennes physics because he was interested in all sorts of things. So we knew it was a new field, but we didn't even know at the time what it was.

But over the years, I think at Exxon, we really developed that field and I guess what a lot of us thought. First, we called it complex fluids but then, it's not complex, so why did we call it complex fluids? And then there was a French term, soft, condensed or soft matter, but de Gennes didn't like that, but still it's term that stuck. But I think that Exxon, more than any at any other place in the world in those days, helped develop and establish a field of soft matter because there was a driving need for it. There was a recognition that this was the kind of science that would have the most impact on a petroleum company. And it was the kind of science, the kind of basic science that in condensed matter physics, that should be done. But I think that was one of the really exciting things about being at Exxon, was that the whole field of soft matter was more or less established.

I'm not saying that there weren't a lot of important work elsewhere, a lot of contributors elsewhere. There were and I'm not trying to detract from anything. I'm just saying that there was a really exciting time where it was being established. And I think you could realistically say that Exxon had a huge impact on the establishment of soft matter in the world in those days.

Zierler:

And what is the significance of the term soft matter? What does that mean?

Weitz:

So I have my own way of describing it. It's an important question, because in the early days, whenever you gave a talk, you had to explain to a physics audience what soft matter physics was. You didn't have to explain what solid-state physics was, you had to explain soft matter physics. And so I said, well, look, are you sitting on a chair? Right now, are you sitting on a chair? I'm asking a question.

Zierler:

Indeed, I am. Yes.

Weitz:

Are there arm rests on the chair?

Zierler:

There are.

Weitz:

OK. Grab the armrest. Grab it with your hands. Now bend it.

Zierler:

It's not happening. [Laughs]

Weitz:

Not happening. Pinch yourself.

Zierler:

That's happening. I can do that.

Weitz:

There is hard and soft.

Zierler:

[Laughs]

Weitz:

OK. So soft matter is materials that are real easy to deform, that aren't fixed in place, that small forces can deform. So if you can deform it yourself, or other things can, even just temperature. Where it's a whole new field, you have to think about things very differently. And you know, what interacts with your body more, something that can deform you or something that's rigid. Well something that's rigid is what solid-state physics is about. Something that deforms and interacts with you, that's what soft matter is about. And that's how I describe it.

Zierler:

In a Venn diagram, how big would the shaded area be with between soft matter physics and rheology?

Weitz:

That's a good question. I would've said that the circle for soft matter physics is enormous and rheology is a small circle that exists inside of that was a little bit on the edge.

Zierler:

OK.

Weitz:

And that's only because, this is not in any way negative, it's just that to me, soft matter physics encompasses everything. And what I've learned, and this is what you learn when you do this, when you start a new point. Wait I didn't start it, when you're part of a field like this, at least that's the way I think about it. When you're part of the field that's emerging and I think it's emerged now, but it took a long time.

Somebody once told me that any physics department that ever asks, is this physics? And then doesn't go in a direction because they say it's not physics, that physics department is never going to be a good physics department because it's going to miss things. Because physics cannot be so static, so internally focused that it misses the breadth, the new directions that we can go as physicists.

Zierler:

I'll share with you, Bert Halperin, who I talked to a month ago, you know, he told me that early in his career, people used to call solid-state physics, "schmutz physics," because it, you know, it didn't rise to the level of, you know, real classical physics. [Laughs]

Weitz:

Exactly. And as a soft matter physicist, I came, you know, what, ten years after Bert, right? As a soft-matter physicist, you got the same, uh, you know, we used to say, oh, it's maybe "schmutz" physics because it's not even solid-state. It's not the crystals, not the beautiful crystals. It's something that's disordered, it's all junk. And that's what we study. And it took us a long time to do it. To convince the physics community that there's beauty and elegance.

Zierler:

Dave, I'm curious in another way, in a way that Exxon may have emulated Bell Labs. Were you encouraged to publish and to collaborate outside and to attend conferences just like you would if you were at a place like Bell Labs or if you were in an academic department? Did Exxon encourage scholarship in the traditional way that we understand that?

Weitz:

So the answer is, absolutely! But just to give you a sense of the culture, it was a changing culture, right? So the new management had to convince the senior management of the company that came from the corporation.

Zierler:

Right.

Weitz:

Oh, we should get people to publish. Okay, well how do we get people to... well, you know, to patent, we pay people whenever they file a patent.

Zierler:

Right.

Weitz:

Why don't we pay people whenever they publish paper? So they actually thought about paying you to publish a paper. And so they had to say, no, no, people want to publish papers. Let's just encourage. But, you know, they encouraged publication and they encouraged real scholarship in their own way. And that lasted for a number of years.

You know, that changed even in time when I was there. Corporate America lost its shine. I think they realized, in fact, just before the ultimate demise of Bell Labs, I think they realized why they would never be Bell Labs, and why, in the end, Bell Labs failed. And that's because Bell Labs was really more of a national lab that was run by a company because it was not a private company. In those days, AT&T was a monopoly that was regulated. And they were, you know, every time you made a phone call, you paid a certain amount of money for the phone call and some fraction of that went to support Bell Labs. That was part of the regulations.

And so they could do that, they could afford that. But you couldn't do that as a for-profit company. It took a while for companies realize that. Also, the management of companies became much more interested in the real bottom line than in knowledge, culture, and whatever. But in those days, that's one of the reasons why Bell Labs was so successful and why other private companies were not.

Zierler:

Who were some of your key collaborators during your time at Exxon?

Weitz:

Who did I collaborate with? Well.

Zierler:

Both within and beyond Exxon?

Weitz:

Yeah. Yeah, I'm thinking. Did I collaborate? I'm not sure that I collaborated so much with. Well, with some people in Exxon. The people in Exxon I worked with were somebody named Harry Deckman, who is still at Exxon and is not widely known, but is one of the best, most creative people I know. He thinks differently than everybody and I just love talking with him. I mean, the people I remember there were Hubert King, who's still there, Cyrus Safinya who went to Santa Barbara, Fyl Pinkus, who was there for a few years. I certainly talked a lot to Tom Lubensky and then Dave Pine. I collaborated a lot with [Dave Pine]. He came to Exxon. Paul Chaikin, I met at Exxon, and I've sort of collaborated or worked or talked to him for the rest of my life. He's at NYU now.

There's a guy name Joel Gersten, who collaborated with me in the early days when I was trying to figure out what to work on. He came with a problem and I worked with him for a number of years. Also, Abe Nitzan. Then Ping Sheng was a theorist there that I worked with a lot. Tom Witten was someone I worked a lot with and I published a couple papers with him. But he was very influential. He'd come up with his new theoretical concept and it had a big impact on the theory and experiments I did. So there are lots of people.

Zierler:

Did you have postdocs at Exxon?

Weitz:

I had postdocs after a few years. Not at first. At first, I had just technicians. And then I always hired technicians a little differently than other people. I didn't hire sort of career technicians because I always felt that too many of them were not that active. They didn't do that much. So instead I hired people who were, I always tried to find people who had graduated and ultimately wanted to go back to graduate school, but wanted to have a year or two off. And they'd spent a year or two with me. So I hired people like that.

So I had a few technicians, I think I had two sets of technicians, each of them lasted two to three years. Both of them went on to graduate school. And then, you know, the downturn started. Then I hired, they wouldn't let me hire technicians, but they did let me take on graduate students. So I had some graduate students. Again, one or two. And then finally, I could hire a postdoc and then I hired some postdocs.

Zierler:

What do you see as your most significant accomplishments during your time at Exxon?

Weitz:

Scientifically?

Zierler:

Yeah.

Weitz:

I worked on three things, three or four things. What did I do? What do I think that were probably the things that had the most impact? Things that probably had the most impact were the early work I did on Surface-enhanced Raman Scattering. My contribution was OK, but not great. I had some role. Then I worked on fractals and I worked in colloid aggregation. I think that was an important thing. I think the work that I did had a big impact. It was a time when people were just starting to think what fractals were and if you wrote fractal in the title of a paper, you could get published in Physical Review Letters, which is where you published those days, you didn't publish in Science or Nature, you published in Physical Review Letters.

And so I realized that, actually Tom Witten was the person who first pointed out that this is diffusion limit aggregation, which was a theory, and he showed that you saw fractal structure. I had been studying that for other reasons, and I recognized that it was the same thing. So we started doing that and showed that colloid aggregation was an example of fractal growth. And that was a very timely thing and fit it really well. So that was probably pretty influential.

Zierler:

And what was so exciting about fractals at that time?

Weitz:

Mandelbrot was just a proponent of them. His was a non-integral dimension, something had dimensionality different than one, two or three. What were the implications? What do they tell you? It was just an exploration, it was just a booming time to explore that notion.

And most of it was theoretical. And we were doing real experiments that you can really see the impact of something that grew as fractals. And you could understand why it was important. You could understand why it made a difference. And so, of course, there are many other experiments that did that. Ours was really among the first though. So that was interesting and very insightful. And very, I think, had a big impact for those days.

You know. Then we did diffusing wave spectroscopy which was very impactful for a number of years because it was recognizing that you could learn something from very, very strong scattering. Where usually all scattering experiments are done in the weak scattering limit. And we showed that you could go to the very, very strong scattering limit and still learn something. It is practically important and fundamentally important. So that was probably pretty impactful. And then the other thing we did was, again, all these were done in collaboration with people, so I shouldn't take credit for them or I should share the credit with other people.

We did something that ultimately came to be called microrheology. And I made a mistake that I didn't come up with a good name. So, it was recognized by some people as microrheology, but it was. And the work was certainly well recognized. That's also been something that’s been very impactful and it's probably the first experimental work that actually showed that you could do that. So that's doing rheology, but without actually even making contact, making mechanical measurements without even making a contact. And so the fact that you can do that is really an amazing thing. But I think that was also important.

Zierler:

When your time was coming to an end at Exxon, were you trying to stay ahead of the curve in terms of leaving before the whole economy sort of had a downturn or you were before that?

Weitz:

No, I always say that I came in early enough that I turned on the lights, and I left late enough that I turned off the lights.

Zierler:

[Laughs]

Weitz:

And that's not to say there are a few people who stayed a little longer, not that much longer. And a few people who surprisingly stayed their whole career there and have done very well. And I'm very proud of them that they managed because it didn't look like you could.

Zierler:

You couldn't be involved in basic science research and they found a way?

Weitz:

Well, no, I'm not saying that. You couldn't survive. You could even remain working at Exxon. I remember, you know, when I was there, there were two people, two groups of people came. You came as a more senior person or you came as a junior person. People who came fairly early on, it was always this observation that you had that by the time they turned 50, they started to get less happy. By the time they were 55, they were really unhappy and by the time they were 56, they were gone. Never fired. Never fired. They just left.

As I became more aware of it, I talked to people I knew and they said it's the same in all industry that they don't want people to stay on. And so it was difficult. It's not impossible but it's difficult to stay on. Now, I think it's not the case. I mean, it was very much the, you know, the Jack Welch school of how to manage a company, how to evaluate people. So you were evaluated every year, it was very competitive. You never had tenure. There's no such thing as tenure in industry.

But, you know, it's just what happened. Now I think there is a recognition of the value of experience. And so the people who stuck it out did stay on and have good careers, but they had to change direction. The ability to do basic research stopped a few years before I left. And if you were doing basic research, you had to somehow find a way of hiding the fact that you've been doing basic research.

So certainly for the kind of research I wanted to do, I knew I couldn't do it at Exxon. And I also thought that to be successful at Exxon, I'd have to do what I had vowed never to do at Exxon which is sort of move a little bit into the management. I probably would have had to spend a couple of years in a different lab and all that sort of stuff.

Zierler:

How did the opportunity at Penn come about for you?

Weitz:

I'm sorry, how did it happen at Penn? Oh. So let me tell you a different story, and I'll tell you how that came about. So I looked for two and a half years or one and a half years to find a job. I really wanted to leave and that took me a long time. And, my friend, Noel Clark, at Colorado, I saw him actually in the Zurich Airport. I was going with a friend of mine who I worked with, another person I collaborated with at Exxon, named Rudolph Klein, he was a visitor at Exxon but he worked in Switzerland. And I visited him as a part of a collaboration. We were going to some meeting together.

And we were sitting in the airport and we saw Noel, and he said, oh, there's a position at Colorado. And I always wanted to go in Colorado because I loved mountain climbing at the time. I used to do a lot of mountain climbing. So, I just thought that would be the best thing.

And so I applied and I just kept pushing, please, you know, kept being persistent. And finally they said, you know, back and forth, back and forth, that they'd love to make me an offer. But, you know, they had no money. It was a junior position. So basically it comes to the point where they would offer me a job as an assistant professor. Virtually no startup, no tenure. You know, you have to work for tenure and low salary.

And I looked at it and I said tenure, I never had tenure in my life. The last thing in the world I cared about is tenure. Equipment, I know how to scrounge, I'll write proposals. I'm really good at scrounging. I can make anything work. I can do anything I want, that's no problem. I'll go to labs at night and borrow a piece of equipment and put it back in the morning, I could do that. Salary, who cares, my salary will go up eventually and I'd be near the mountains, I wouldn't have to spend money on vacations.

So I said, yes, I'll take it. And they said okay, and then they went to the dean who said, “What? You're offering somebody who should be tenured here an assistant professor position? You can't do that, it's age discrimination.” So they couldn't offer me the job. It was a great disappointment.

And so at the same time, Dave Pine, a colleague and a friend of mine at Exxon was also looking for a job. Penn, was looking to hire somebody as they had hired somebody from Bell Labs who it turned out, he couldn't teach, he couldn’t raise funds. He just knew how to do research. But they thought, Dave had been a professor at Haverford before he went to Exxon, so he knew how to teach. They knew that.

So they made him an offer. But then Santa Barbara came along and also made him an offer and he had accepted Penn, but then he turned Penn down and said, no, I'm going to Santa Barbara. Decided he'd rather go to Santa Barbara. So they were left without having anybody. So out of desperation, they made me an offer. So I always say I just lucked out of pure desperation because they couldn't hire the person they wanted, they had to hire me.

Zierler:

I'm curious, what niche did you fill on the faculty when you joined?

Weitz:

Oh, they needed condensed matter. They needed more people in condensed matter. And, Tom Lubensky was there, who was quite influential, and that a few people doing softer kinds of things. So they weren't afraid of that. They of course, since, have become really the center for condensed matter, or, for soft matter. Really a spectacular place, and they built up really, really well.

Zierler:

Were you looking forward to being back in an academic environment? Was that something that was good for you?

Weitz:

So as always, I never look backwards, I only look forward, so yes. I didn't know what it would be like. I didn't realize how really fun it would be. It turned out to be far, far better than I thought it would be. I was so worried I wouldn't be able to do all the things I could do at Exxon. I could do so much at Exxon. I was worried, you know, it was a big move, but it turned out it was only positive. Everything was fantastic. Penn is such a great place. Fabulous colleagues, just fabulous colleagues. It was just a wonderful place. So I probably had some trepidation, but there was nothing negative, only positive things happened going to Penn.

Zierler:

Did you take on graduate students right away?

Weitz:

Yeah. Right as soon as I could. And I was there not that many years but I took two students or three students a year, or four students or something. So I had like six or seven students by the time I left and a few postdocs. Yeah. Right away.

Zierler:

And were you able to build up your own lab or was there a lab for you that you could join?

Weitz:

No, I built my own. And basically, I brought the equipment I had at Exxon. I brought somebody, one of my postdocs from Exxon with me. And so we moved all that and we set it up right away. And they gave me some startup money, but I didn't really need that much because, you know, there was a lot of central equipment that I could have impact on from buying and they had good ideas.

A guy named Arjun Yodh was there who was, again, a spectacular colleague. Just fabulous. And he and I, you know, I had this mentality of Exxon where you couldn't survive without working with people. You could not survive working on your own. So I have the same, I've always had that mentality.

And so his lab and mine were side by side, so it was just the same. So his students would use my lab, mine would use his lab. They were indistinguishable. We were separate, we each did our own thing. We worked on some papers together, but not everything. The students were advised by one or the other, but they interacted as a group. And so there was always cross-fertilization. And that made it so much stronger, so much better. There was always enough equipment. I was able to get started really fast.

Zierler:

So in many ways, you were able to continue on with your research fairly seamlessly from Exxon?

Weitz:

Absolutely seamlessly. I would say I was down for two days or three days to move, and that was it.

Zierler:

Wow.

Weitz:

And then we just continued to work. And it just grew. Because you know at Exxon, you were never equipment limited, you were always manpower limited. And so you had to learn, I think you learned more at Exxon. Better yet, the thing you learned better at Exxon than anywhere else was how to prioritize because you had a fixed amount of time and you better do the most important thing. And you couldn't keep doing the same thing because you couldn't survive at Exxon doing it. So you always had to find something new to do. You had to say, this is why I'm going to do this and I'm not going to do this. So you always could do this, but you were limited. You can only do what you could do. Or if you had a postdoc, what you and your postdoc could do.

And then at university is like being in a candy shop, right? There are so many kids who come along and they want projects to do. And you have all these ideas: I wish I could have done that, but I couldn't. And so there are all these things to do, all these things I want to think about trying to do. And there are all these people who wanted to do it. And there was enough equipment at the time to do everything. So now in university, you're usually more equipment limited than manpower limited although maybe it's changing in this day and age.

Zierler:

What kinds of undergraduate courses did you teach during your time at Penn?

Weitz:

Yeah. So, you know, I worked at Exxon for 18 years and you forget all the formal physics, so I had forgotten everything. I said, jeez, I gotta start teaching. Let me start at the beginning.

Zierler:

Yeah.

Weitz:

Let me teach freshman physics and I taught freshman physics. I want to learn physics and it was so damn hard. I was just stuck at freshman year. I never wanted to teach past that. So I only taught freshman physics, it's the only thing I taught

Zierler:

You probably helped yourself out as much as the students.

Weitz:

No, I mean, I should have. At first, I did, but I should have done other things. But then my teaching has taken a totally different turn. But I've only taught formally in physics class that I only taught freshman physics; I've never done more.

Zierler:

So it sounds like you are quite happy at Penn. So that begs the question, you must have been recruited to Harvard?

Weitz:

Oh, yes, I was pretty much recruited. They invited me. They said, oh, please, will you come and give a seminar? I said, Sure. And I didn't know, I had something to do on Saturday, so I didn't even want to stay over. I didn't go to dinner with them. I just went there; I gave a seminar and went out. I had no idea what they were doing.

In fact, there was another person who, I knew that they were recruiting a soft matter physicist because Tom Lubensky had told me. But I also knew that there were a couple of people who sort of were known within the field to the people that they targeted when they had planned to hire. So I didn't even pay attention to that. And so I went there and, you know, I talked to them. I just I was giving a seminar. I no idea that they were actually interviewing and I had no idea that they were thinking of hiring. None whatsoever.

Zierler:

Do you have an idea, looking back, who was driving the recruitment of you?

Weitz:

It was just the way Harvard does it. That they send out letters, and once they get the letters back, it's very difficult. If they want to hire somebody, it was even more difficult in those days, they had to go by what the letters said.

And I think my letters came out stronger and I don't even know who wrote them. And they had to go back and reevaluate. And they looked into that and decided maybe I wasn't as bad as they thought. Maybe I'd be OK. I think it was just the letters. I don't think they had been planning to recruit me. I think, I guess in retrospect, my name must have been on the list, but it was not at the top of your list.

Zierler:

When the offer came, was that an easy decision or a hard decision for you?

Weitz:

It was an exceptionally difficult decision, exceptionally difficult. Took me a year, year and a half to take the offer because I was very, very, very happy at Penn. And my wife worked in Princeton. So we lived between Penn and Princeton. We each get to live near the place where we work. We had just built a really beautiful house to live. And we lived in a really fabulous place in New Jersey, which we really liked. Now, we put a lot of work into it moving into a place at Penn.

So everything was perfect, and then Princeton also was looking for people and they didn't make me an offer when I left Exxon but they decided they would. So they made an offer. So I could have gone to Princeton, could have gone to Harvard, could have stayed at Penn.

And, you know, Penn was fabulous. I was really happy. Princeton, I wouldn't have had to move. You know, I just drive a little way and instead of turning right, I'd turn left. Would have kept my wife very happy if I'd done either of those. And then I'd have to move to Boston and start all over again, move to a different place. You know, it was a tough decision. Wasn't clear that I should do it.

Zierler:

So what was the deciding factor in the end?

Weitz:

The deciding factor was twofold. I looked at Princeton, and I saw a lot of people I knew who had been there and left. So there's a flux. The person I liked the most at Princeton was Paul Chaikin, but I knew Paul well, and I knew that he was always thinking if he could go to New York, he would. And I didn't know if that would happen, but I could see it happening. And then I also looked and I looked at all the people I knew in soft matter. And a lot of them at Penn or elsewhere had been trained at Harvard.

And I realized that if soft matter was ever going to be a really serious field, it better have somebody working at Harvard to do that. And I thought that was really important for the field. And so it represented a good opportunity for me. Good opportunity to make the field more broadly acceptable to build people doing it. And it just seemed like an opportunity I couldn't say no to in the end. It was very difficult.

Zierler:

Looking back, did that plan play out in terms of your move to Harvard and what they're represented for, the acceptance of soft matter physics more broadly?

Weitz:

Well, okay, I think so. I mean, I think, I know that I, you know, I don't want take credit for myself because they would have hired somebody and give people at Harvard the credit for doing that. David Nelson, people like that, they're the ones who really wanted to, and I think anybody would have done the same thing. So I think the fact that somebody was there doing the soft matter was the important, not just me, that there was somebody there.

For me, it was spectacular. It's a different environment. It's a place where you get a different level of student. Penn is fantastic has done extremely well. It's very important. I would have been very happy at Penn, but I think I also benefited a lot from being at Harvard.

Zierler:

What were your impressions going back to Harvard? Did you feel like you were going back home? Did you feel like this is an entirely new place since you last connected?

Weitz:

Is an entirely new place. Completely different.

Zierler:

How so?

Weitz:

Well, it was a place where there were all these senior professors who had junior professors. You didn't talk very much with your senior professors; you didn't interact much with them. It was known as a place that you didn't interact. The professors didn't interact with each other much. They did, but the students didn't see it.

And when I came back to Harvard, I found that this changed, there was no longer, you know, all the professors were equal. The junior and the senior people, you didn't have somebody working for you. You just worked with everybody. It was a much more interactive place, I think, than I ever remembered it. And I'd never known it as faculty member, I'd only known it as a student. And I had been away from it for so long that most of my perception of the field of physics was formed away from Harvard. Right, for 18 years, so it was coming back to a completely new place.

Zierler:

Did you have a sense when you got there that there would be that uphill battle in terms of ensuring that soft matter would have its equal place at the table?

Weitz:

Well, let me say that the battle was won once they hired me. I don't think that was really because of Harvard, but mainly David Nelson. So my understanding was he said he'd become chair if they hired an experimentalist doing soft matter and he was the one to push the search in that direction.

Once I got there, you know, the first thing. Well, I think people saw that I could be successful. And then we've hired a lot of people in soft matter since then. Again, once you show the world and it's successful, then there's no questions. And so I never pushed. I never had to push. It's just it just naturally occurred because it just became part of the community. So it wasn't that I had to be proactive. I didn't have to do that; I think it had already been done.

Zierler:

Now, you knew the drill coming in from Penn, were you able to just hit the ground running once again in terms of building up a lab and taking on new graduate students?

Weitz:

I think it took an extra day to move, took three days instead of two. But, yeah, we were we were up and running in no time. And the reason they hired me, they hired six people in that era because they foresaw a lot of retirements and they wanted to hire, you know, revitalize. And they hired a lot of people. And so it was an exciting time. I was younger. I had lots of students and no problem attracting students. So, yeah, I ended up having a much larger group than I ever wanted or thought I should have. But it was just this opportunity to do that and I wasn't afraid of doing it. So yeah, there was zero problem getting started.

Zierler:

I'm curious if you could describe, you know, it's interesting the idea that Harvard really sets the tone in terms of where physics is headed. And if you're there, that gives you that unique perch to make sure that the long-term viability of soft matter physics is strong. So, I mean, that makes sense when you just say, well, it's Harvard, right? But I wonder if you could explain how exactly does that play out in terms of, you know, the way ideas are shared and the kinds of decisions that are made based on people taking their cues from Harvard. Right. This long-term goal of ensuring the viability of soft matter physics; how do you how do you follow something like that?

Weitz:

You know, I hate to say it, but it is I think just the fact that it's Harvard, that it has this reputation. You know, there's half a dozen universities. And I would argue that it's probably not deserved at this point. I don't think Harvard has done enough to maintain the same ranking that it used to have. But still, it's got this aura.

Zierler:

You mean physics generally? In terms of ranking?

Weitz:

Harvard generally.

Zierler:

Oh, Harvard. [Laughs]

Weitz:

I don't think. I don't think, I mean, I don't think Harvard has maintained. I think if you look at most objective rankings, Harvard is no longer. It used to be really the best university in the world but I don't think it is anymore. But it's still up there among the top. And I think it's just that fact that just brings a level of people here that you don't find elsewhere. I think it's really nothing more than that. It's just something you can do. You can do things at Harvard. Any one of us at Harvard, if we were somewhere else, wouldn't do as much. We wouldn't be able to. I think. I could be wrong, but that's my own view.

Certainly for me, I don't think I could do as much. I mean, I don't think that is that I'm... I don't think I'm that much better than any of the people who work in the same field as me elsewhere. I think that just being at Harvard gives me a bit of an edge over many of them. It makes things a little easier to do. Again, a little bit better students, a little bit better postdocs. I have to struggle harder for funding because people don't want to fund you if they think you're at a rich place. But it just gives me a little bit of an edge. That's what I think. I could be wrong.

Zierler:

Can you talk a little bit about your position as director of Harvard Materials Research, Science and Engineering Center? How did that come about?

Weitz:

Yeah, I'll say this. I'm in the last few months of that. Somebody else is taking over which is good.

Zierler:

OK. Congratulations.

Weitz:

I had that position for twenty odd years, yes. And Jennifer Lewis, wonderful scientist, is going to take over. She'll do great. But, you know, well OK. What happened was that Bob Westerfeld was the director at the time and just soon after I arrived, Bob applied for and successfully got one of the new centers, a nanoscience center. And so he was going to direct that since he got that. So somebody else would have to do the MRSEC. I think I was probably the only person around who could do it. A lot of other people had done it, and there were other people who were younger and didn't make sense. And so I did. I decided, OK, I'd do it.

And I did it and we were successful; we were successful the next time. The third time that I put the proposal in, Jennifer had already arrived and I thought she should do it, but she didn't want to. So I did it. And then finally, I was able to convince her that she should. It's just too long for one person to do it. But you know, it's not that much. I should say, it's a lot of work, but it's I think the thing I like about the center is that I can take... The people who are part of the center, if I need help from them, I can get at almost immediately. Everybody who's part of it recognizes that this is like, I call it a glue center. It's a very low funding, but everything that we do is collaborative. So it's the kind of thing that seeds funding and seeds collaboration across the university. So it's really important to build a community. That's what it's done.

So I remember, must have been by now, seven years ago over the Christmas holidays, we got back, just because of the way schedule, we got back reviews of our proposal. We had to submit a revised proposal because of the reviews. Went from the pre-proposal to the full proposal. We had to really change things. We got some bad reviews and one of them, one of the groups.

But George Whitesides, who's one of the most distinguished professors at Harvard. Very, very busy. But he's really one of my real, I think he's just he's one of my real heroes as a scientist. And he spent the whole Christmas holiday working with me on revising his proposal because we need to do it. And it's that, you know, he agrees with my perspective that is this is one of the really important grants. It's not the money, it's the community that it establishes. So it was the kind of thing that everybody who is part of that, who's really core part of that, is willing to work very hard for very little money because of how important it is.

Zierler:

When did you start to get interested more in the biophysics and biomedical engineering issues?

Weitz:

So when I first moved to Penn, we had just, I mean, basically, it was a student who did it, who figured out microrheology. It's a guy named Tom Mason, he's now at UCLA. But the two of us recognized it's importance, and I wanted to explore its meaning. And another friend of mine who had also been a postdoc at Exxon, that's how I knew him. But he was at the time at Michigan, named Fred MacKintosh. He had been telling me about his work he was doing, which he was studying actin fibers. And I realized that was a beautiful test system for asking: how well does micro rheology do to study different systems? So I thought that seemed like a good thing to do.

So I started doing that and that naturally leads you into thinking about biology because actin is sort of a biological system. And so I just started thinking about it more and more. It just was, you know, seemed like a natural thing to do. And so I did that. And then again, you know, from the old Exxon days, I worked on emulsions for years at Exxon. And so I was really interested in that, we were doing some work emulsions.

And then I saw Steve Quake, you know, one of the real leaders in microfluidic talking about making vesicles with microfluidics. But I would call it, he was making emulsions. I think he was using the wrong term. He says, no, he's using the right term. I say he's using the wrong term, doesn't matter. I said, but I'm trying to make vesicles. I was trying to make vesicles using emulsions. I said maybe I can use microfluidics and overcome some of the problems. So we started doing that. And, again, we didn't know what we were doing, just trying to learn something and try these things. And we started getting a lot of beautiful results, but not really understanding their implications.

And then I went, I spent every year in those times until now, I spend two weeks in Paris visiting a former postdoc and now a very big collaborator of mine. And he told me, he was the one who taught me about emulsions when I was at Exxon. He said he had a student who was thinking about doing things with drops and stuff that we did in microfluidics might be valuable. And we looked into it and we realized that the applications of the emulsion work we were doing in microfluidics to biotechnology and biology, assuming biotechnology, were enormous. And once we did that, we just realized that that's what should have been doing right from the start. So it was all accidental. No great plan.

Zierler:

Was there any particular satisfaction in doing research that might advance human health research or have medicinal value?

Weitz:

Absolutely. Absolutely. Absolutely. I claim to you that I know it's being a little brash, but I know how to design a test for COVID that we could produce at five dollars a test. Three dollars, I think. That we could manufacture in the tens of millions per day. That we could administer without having any expertise. So it's totally distributed, so you could do tens of millions of tests per day and could make this country safe. I'd love to do it. I mean, I'm not, nobody will listen to me because I'm not known for doing diagnostics, but I think I could do it. I hope somebody does it. I try and do it but, you know, so I get all these ideas, sure. You know, once again, it's what should you do not what can you do? What should you do? That's one thing I should do. I don't always do the things I should do because I can't always do it. But it never stops me wanting to do it.

And I think that there are many other things that we do. That's just the thing I've been thinking this week, right. There are many other things that we've thought about that, to me, have the same appeal. A lot of it, I admit, a lot of it is through ignorance because I don't know enough of the field, so I think I'm always optimistic I can do something new. But my own view is that science should be motivated by ignorance. You should do things you don't know about. If you know.

So I always tell my students, never read literature. First do the experiments then read the literature because nine times out of ten you'll do something that somebody else has done. Chances are you'll still take a different perspective. So you'll still learn enough but that one time in 10 when you've done something new, it’ll be totally new. And if you read the literature first, I don't know anybody who's really smart enough. Or, I know very few people really smart enough to be really insightful to know: this is the one most important thing that connects these things in different directions.

Usually once you read the literature, you get distorted by what you've read and you just do something that's incremental, something else. If you want to do something that's really different, I think you shouldn't know too much. And that's where I am. I think a lot of things I say probably are nonsense and will be proven nonsense. But one or two of them won't be. One or two will have an impact.

Zierler:

And it's worth it for those one or two, you're saying?

Weitz:

Exactly, exactly. It's worth it for that 10 percent because they'll be really different. That's what we should be aspiring to do.

Zierler:

Was that particularly exciting for you when you are co-director of the Kavli Institute for bio-nano?

Weitz:

No, that was sort of a lot of work, but it was OK. It was, look, the center there is great. It's fantastic. But it's a prestige thing. So to do that, the dean at the time was very powerful, insightful, brilliant fantastic dean. So we had to get them to put an institute. So the amount of money that we had was really minimal. And so we had to find ways of making it look like we were doing a lot more than we could do. We, you know, we had to have a space, but we didn't have money. We weren't a state university that could just go and ask for a building and call it the Kavli Building. We're a private university, so you can't get anything.

So we had to just call this room. We put a sign up. This is the Kavli Room. It was a meeting room. So it wasn't going to be named by anything else. We called it the Kavli Room and we had to do something with the money that would, it was a tiny amount of money and the university is supposed to match it, but they never really did it.

So we had to do something that made a difference. So we had to find a clever way of spending the money and having an impact. So what we did was we gave it to theorists, told them they had to use the money because they're cheaper, but they had to collaborate with experimentalists. And so, again, it engendered a sense of community and that sense was very valuable.

Zierler:

Now you have an ongoing appointment with the BASF advanced research initiative. What is that?

Weitz:

Well, I just had a meeting with them just before this one. That's why I was a little late. It ran over. So, BASF, must be now 12 years ago, 13 years ago, actually 15 years ago, they sent around people that were scouting and they came and talked to me. And I think I know better than most of my academic colleagues, I know what industry is, so I know how to talk to industry people. And so I started talking with them and we hit it off and they started supporting some research in my lab.

Zierler:

BASF. They say, "we make things better," right? That's them?

Weitz:

They are a chemistry company. They're a one hundred and sixty-year-old chemistry company that still does research. There aren't very many places like that. So they're a spectacular company in my mind, really spectacular. And I got wind that they want to start some kind of research lab in the US.

At the time, they hadn't bought companies in the US. They hadn't acquired companies in the US. They had no presence in the US. They wanted to establish something in collaboration with a university. And I think they were going to do it somewhere out west. I said, oh, well, if you're going to do that, why don't you come to Harvard. Of course, they didn't think that was realistic, but they came and I sold them on the idea of doing something.

And I convinced that we could do something where they could establish some operation, where they could support research but we would arrange it so that it was not the traditional way of supporting research. They wouldn't be calling for proposals that faculty would submit to because, I said, if you do that, you just going to get things that the faculty want. Instead, they'd come and they'd have people who'd do some scouting. I'd help them. We’d find things that people in the university wanted to do, but they would decide what they wanted. They would make the decision; this is what they think is important.

And so they liked that model and they like the model of how they saw that they could get faculty to work together because we did in the MRSEC. And so they established sort of a collaboration where they just support. They have somebody who works from BASF who's stationed at Harvard, but they just support postdocs and they said they'd support up to 10 postdocs a year, maybe 20. But they support as many as they can afford and they can find. Sometimes it's three, sometimes ten, sometimes twenty. And it works really well. And it was just a great way of getting an industrial presence.

But, so, we do research that's relevant to them, they had the final say. It only worked if they had somebody who was at BASF who would interact. So it worked really well. And it was a really good model for industrial support. So much so that the next time, it was a five-year plan, the next time they did it again at Harvard but they broadened it to people at M.I.T. and UMass. And by the time they did the next time, they also established similar centers following the same general model in Asia, in the West Coast, in Europe. They have three or four centers, or four or five centers now, around the world with the same model.

And so it works really well. I think it's a good way of having industrial collaboration. It's a way of doing something that's relevant for industry, that makes a difference to industry. And it has to make a difference for industry because they're funding, so it really has to add benefit to them. It's a way of adding benefit to industry doing research at the university. I think it has worked well.

Zierler:

Dave, I want to ask you about your entrepreneurial instincts. You have many patents and you've started many companies. So I want to ask broadly, when do you know that there's an area of research interest that has commercial or market viability? How does that happen in terms of you saying, you know, this is beyond just the science? There's a there's a company here. There's a there's a marketed idea here. How does that happen?

Weitz:

You know, it happens in a variety of ways. Usually, if I do something that I see that's really something we do, but we can't do it, university group takes a lot of engineering, and I think there's a market there. And sometimes it's because people keep coming to me. I always say now people in Boston know who I am, just in the local area. Somebody comes, please can you help us with this? And we help them. And then sometimes we do something that's useful and then their friends come and say, well can you do for us too? And other friends come. So many people that we try to commercialize it. Other times we just see there seems to be impact or people come to me and say, why don't we do this? It varies. I don't think I'm at all... It's an imperfect science.

So there's things that I think, in retrospect, I should have patented but I didn't. There are other things that I patent that have no value. There's a lot of companies that we think are great ideas, but the market doesn't support them, so we start things that aren't useful. Other times I miss things completely. It's a very imperfect thing. You just try and do the best you can. And it's just when do you think there's a market for something when you say something will have an impact that's not something you can do through government funding and get things done.

Zierler:

Have there been any patents that you've had that have really taken off in terms of economic value?

Weitz:

Well, depends how you ask that or how you look at it. Look, I always say that Harvard is not for profit, so they shouldn't make a profit from their patents. And most universities that make big money from patents do it on one or two patents. These are drug patents or algorithm patents. That's where most of the money in university patents come from because you can't get around them. If you have a drug, you can't get around.

But process patents, which are the things that I do, there's always a way around, so they can't be too valuable or somebody will find another way of doing the same thing. And, so then, why do you do it? Why do you patent it? You shouldn't be doing it to make money. Okay, you make a little money but the goal should not be to make money it should be to have impact. And often the best way to have impact is make sure that companies start. But even then, you shouldn't necessarily make money.

So if I ask the value of my patents, I would say that a lot of them have been licensed and are used in companies and that's good. Some of them have been used to start companies. A few of them paid enormous amounts of royalties for patent process. I think one of the patents last year or the year before was among the highest paying patents in royalties for Harvard that year. But, you know, it was a conspiracy, a bunch of things conspired that that became a very valuable patent for technical reasons for a company.

And so they use that patent for a lot of detailed technical reasons that it had to do was a priority date. They could put other things on and they have their own patent. So they wanted to keep it of value. But I think, to me, the most satisfying part of it is not the economic value, but just the technical value of seeing things have an impact on the world.

Zierler:

It's also one way of measuring value with the number of jobs that these ideas create.

Weitz:

Absolutely. Absolutely. And so here I have a way of looking at it. My group for a while, I don't think it is anymore, but for a while, it was the biggest group around in the physical sciences at Harvard or among the biggest, not necessarily the biggest. It was a very large group. And I’ve had 160, 170 postdocs work with me. 50 students or something. It is a lot of people. And how many jobs do I have? I have one job. What right do I have to train 200, 250 people for one job?

And, you know, big industries aren't hiring. So I think we're being irresponsible if we train that many people and we don't worry about where they go. And so my personal, this is just for me. Everybody will do their own way. For me, my personal criteria is I look at: how many jobs have my companies created and how many people have I trained. And if the number of jobs is greater than the number of people or least equal to, then I think I've done my job. If it's not, I think I’m being irresponsible trainings so many people.

And I don't say that they have to go work for me, I just want to have a balance in the system. And so by now, enough companies have come from my group that the balances weigh in favor of the job side. But I think I have to do that. I think you have to pay attention to that. Otherwise, you're being irresponsible in training.

Zierler:

Maybe, but that's also a very unique approach to put that burden upon yourself. I don't know if I've ever heard that before, actually.

Weitz:

You know, I don't ask anybody else to do it. I don't care what you do. I mean, it's just, you have to ask, if you do things, you have to ask: can you do things in a responsible way? And if I'm training people, I don't want to train them for nothing, right? Otherwise they should do something else. There are so many things the world to do.

So if I'm training people, I think that I have to be responsible about that. I don't have any right to train so many people if there's nowhere for them to go. When I was younger, when I was a student, then industry was hiring, there were all these other places people would go. Now it's the startup companies that are hiring. So you have to ensure that they're there. Otherwise, we have no right at a place like Harvard, we have no right. I mean, that's not true, most of my people will go to other places, some go to startup companies, some will go to big companies, others will go to academia and Harvard will fill the ranks of many academic institutions.

But still, that's, you know, I think if everybody worries about the number of people that we train and what they do, I think the field will be stronger. And I think it's the only responsible way of doing things. I don't think we can just train, especially a group like mine, which trains so many people. I don't think I have the right to do that without worrying about where they go.

Zierler:

I want a lighter question. We don't have to think about the fates of all of your graduate students over the course of your career. When did you get involved in the science and cooking concept? How did that start?

Weitz:

It started because a postdoc who worked with Michael Brenner came to me and he says he wants to invite Ferran Adrià to come and give a talk.

Zierler:

Oh, wow.

Weitz:

Because the guy talks about science and cooking. And I looked at him and said, who's he? I never heard of him. And, so he told me and I said, well, he'll never come to Harvard. And I said, well, I can invite him as part of the MRSEC. It's good, but the MRSEC is not, you know, we have some money to invite speakers, but very little, we can't pay him an honorarium. Why would a famous chef come to Harvard to give a talk? So he says, oh no, let's just invite him. So I wrote a letter and invited him, and three days later he says, yeah, he's coming. And the person who's most surprised, of course, is me.

And then he came and I'll never forget my experience. He came and I didn't know what to do. I knew nothing about this but I had to organize it. Let's have a public lecture, a colloquium. Those are different days, so of course, I didn't pay attention to it, I never was good at organizing. I went around and finally, a week before said I better do this. And all the big conference rooms, the big lecture halls, were booked, so there's no place to have them talk except for the physics colloquium room where we give our colloquiums for physics. That seem like a beautiful room. It had just been refurbished, this beautiful room. I knew it very well. I knew that it had 215 seats. Huge number. No problem.

What I didn't know was, didn't know anything about social media, I didn't know that the Boston Globe did an article about him the week before. I didn't know that people would tweet or whatever you do in those days on social media that he's coming give a talk, first come first served. And he arrived and this talk was at 6:30. First come, first serve, no tickets.

At 3:30, I walked by the room just on my way to my office and there were people in it and I just couldn't believe it. At 4:30, I went there and it was so full, there were people in the aisles that it was unsafe. I had to call the campus police so they would keep people out the aisles for safety, for fire safety. And so at 5:30, I went to the overflow room where we were going to live cast it by web, which you did in those days. We were going to do that. I went to the room that we had to do it and it was full. So then I had to find another room just for that. I had never seen something like this, it just doesn't happen for physics. It just doesn't happen. I'd never seen it.

So he gave his talk and then afterwards we were talking, what could we do? I realized it was a real occurrence, what could we do? It turned out that he had a lab. And I thought about it, and I said, OK, maybe I'll go visit the lab, but I don't think the kind of experiments I do and the kind of experiments you do are the same. You test lots of recipes and taste them. Me, I try and figure out what's going on. I don't think you really care about what's going on. To some extent, but not the way we were. But teaching. He said he wanted teach chefs more science, and I wanted to teach nonscientists, I wanted to have an excuse to teach science.

So he said, let's offer a course. And then my friend, collaborator and co-conspirator Michael Brenner came along and he's on a Harvard committee and he said, “Harvard’s looking for classes that we can teach that are general science. Why don't we do this?” And, of course, so it was his vision to do it the way we did. And we started it and it became this wildly popular course. You know, people want to study science. I always say that I teach freshman physics, and I think it's important because I'm trying to teach them, you know, these guys may be my doctor one day.

Zierler:

[Laughs]

Weitz:

When I'm old and decrepit, I want them to understand a little bit of physics. But, you know, they don't want to do it because they want to become doctors, they don't want to become physicists. They hate physics. They just have to do it, they hate it. So they already hate you and then the dean hates them because the dean puts the class at 8:30 in the morning. So you had two strikes against you. They walk in and they hate you because you're teaching them something they have to learn, not that they want to learn, and the dean has put it early in the morning, too early for them.

So it's not very rewarding. So if you can find some way of teaching students how to enjoy what they're doing in science, then you're home free. And that's what the class does.

Zierler:

Is that a challenge not to make it a fluff course? To show that there's real physics involved behind cooking?

Weitz:

No, no. Now, I mean, what people don't realize is that when it started, it's broadened now as we teach a lot more. But when it started, it was just a way of teaching a soft matter course. And if I went and told my colleagues, I want to teach freshman physics as soft matter, they'd say, wow you're not teaching Newton's equations, not teaching magnetism. I could tell them, you know, if they're my doctor, they don't need to know Newton's equations, they don't need know electromagnetism. They need to know how things to defuse, how fluids flow, all the things I teach in soft matter. All I would teach if I taught a soft matter course.

So that's what I want to teach them: elasticity and squeeze, all these things they need to know. But I'd never be able to do it. But here, I can just take a soft matter curriculum and just theme it around cooking. And that's how it started, now it's broadened so we teach a little bit more. But it's more or less that. It's a science curriculum, but we teach it from cooking. And I'm experienced enough now that I can take almost any recipe that a chef does and I can find those aspects of it that I want to use to inspire the science I want to teach. But it's really a science class.

Zierler:

I can't help but ask, has this course improved your cooking? [Laughs]

Weitz:

No, no. That's the beauty. So, look, this is a class where you can collaborate with the best people in the world, right? So I always tell the chefs, you do the cooking, I do the science.

Zierler:

[Laughs] And probably everyone is better for it that way.

Weitz:

Well, there was one person who is one of the most wonderful, the chefs are just fabulous. They're really the best people in the world. They're really fantastic. And they're experimenters just like me. One person I met. So have you heard of José Andrés?

Zierler:

Yeah, I have.

Weitz:

So he was involved. He was a friend of Ferran. He's been involved from day one and his restaurant enterprise put in 5,000 dollars, the first support I ever got for my classes, every couple of years. He's one of the most remarkable, amazing people. He wasn't quite at the same level of his career at the time when we started. But we got started and he said, well, come down to Washington and I'll introduce you to some people. Let's think about how to do this. And we went to Washington. He showed us his restaurant, took us to his restaurant. He says I'm going to introduce you to a friend. We're going to go to the friend's office.

So, okay, where do we go? Went to the White House and the friend was the pastry chef. At the time, Obama was the president. The pastry chef took us to the little room, in the middle of nowhere, where he did pastry. We had to duck out of the way because Michelle Obama was walking by and we couldn't be seen. But his name was, oh s***, I'm so bad with names. I'll think about it. He again is one of the most wonderful, warm, kind people. Bill. Bill. Bill. Sorry. I'm sorry, I can't remember his name.

Zierler:

It'll come to you.

Weitz:

I'll say it when it comes to me. But he came for many years and he was really interested in the science. So I have pictures of him taking a picture with his cell phone. We were projecting his dessert, which was a dessert, it was an emulsion or a foam or something. We took it on a microscope and we looked at it and projected it to the students and I have a picture of him taking a picture of that. And he said he really wanted to understand the science. So what was the science we were going to teach? And so, you know, elasticity. OK, he's going to do something with elasticity.

So he came and he started talking and he started talking about charge. And I realized he had heard electricity, not elasticity. And he thought we were talking about electric things. But it was fine. He left the White House, and I think he started a restaurant recently in New York. His name is Bill Yosses. But for a number of years he did basically outreach, which is what we do now.

We use this not only to teach and we have public lectures. We teach high school students, public school kids. We do this, we really use this whole idea of science and cooking as an outreach tool. And he went and he worked doing outreach for a couple of years because he appreciated it so much and only went back to cooking more recently. That's when I realized that, oh you cook the deserts, I'll talk about the science. You're really good at that. I'm probably okay with the science. So I don't cook. I love to eat, but I don't cook. I let the chefs do that.

Zierler:

[Laughs] Dave, what have you been involved with in recent years? What's your research been focused on?

Weitz:

Well, let's see, what's the most exciting thing? The most exciting thing right now are, we've done a lot of work on trying to do biotechnology. So we've done work on trying to do a lot of very, very sensitive detection of biomolecules in blood. Very pragmatic. And that's why I say, you know, this is why, to me, testing for COVID is just using the same things, so I understand a lot of what's necessary. I'm not a biologist. I'm not even a biochemist. I don't know the details of that but I know enough of the concepts to know what I should do.

And so we do that more for human health, for trying to make it for public health applications. Not thinking of COVID, but thinking of... this was before the COVID situation, thinking of food safety and things like that. We did it for trying to look for biomarkers for identifying cancer. And so we've developed the technology that does that. So a lot of that, the interesting thing here is just the technological applications. I think could be important. And those things are things that we spawn off into companies. We don't do it in our lab.

We worked with some people to do a single cell sequencing. Again, we help with the technology, but now the people who do that have overtaken us, so I don't I don't want to work on it because I can't be competitive with biologists, but I think we helped with the technology.

So now I'm quite passive. I really would like to do this detection system, this testing system for COVID. I just think it's going to make my life easier and everybody else's life safer. We're doing other kinds of biotechnology things. Well, again, these are probably things are going to get done more in companies than my group, but we have new ways of looking for drugs. I'm not an expert in it, but I'm an expert in the technologies that allow us to look for them.

So those things are really exciting. A mix of very pragmatic and practical stuff and has to get companies and stuff I can do in my lab. It's all motivated by the science I do, and my motivation is really to help human health. That's what I care about. Even though for the drug companies, you can get funding because you go to venture capital world and they'll fund this stuff because they see the financial rewards, I see the societal rewards.

I'm doing, we still make materials using microfluidics. We can make new kinds of materials. Again, the practical thing is we, a company we just finished selling a year ago, but finally sold five years ago, it made cosmetics using microfluidics and it was way of making cosmetics but now there are other kinds of things. I'd love to do the similar thing for drug delivery. I think we know how; we just haven't had the ability. We're not experts in that, so we have to collaborate with people. Call us over, drug delivery, we can do that. But I'd love to do something that makes a difference there.

And then we've done work that's an area that's not particularly popular, but I think it's exceptionally important. So we don't worry about things right now because of the pandemic. But before that, what's perhaps not so well known is that the US has become completely self-sufficient in energy. And that's important because when I first started working at Exxon, you probably don't remember it, but there were these first oil crises, two times where the beginning of OPEC there was a recognition that our oil came from Saudi Arabia. And people waited two hours in line just to fill up their cars at the gas station. And that changed the economy and changed also the geopolitical situation.

So for a long time, countries in unstable, less than favorably interacting countries had enormous amount of political impact on the world. But because of three technologies, this goes back to my Exxon days. Because of three technologies, things have changed enormously in extracting oil.

The first one is horizontal drilling. So you no longer drill straight down, you drill this way. The second one is using multiple scattering of sound to identify where the location of oil is. And the third one is fracking. And so fracking has become very political and very unpopular. People say they don't want to use oil. I get all that. I get all that. But still, right now, it's pretty comfortable. But if it gets hot, I'm going to turn my air conditioning on. Where does the energy come for that? It doesn't come from solar or hydro yet. It may eventually, but it doesn't now. And in the winter, I’m going to heat my house. And it's heated with, well I use natural, no I use oil. And people don't want to stop heating their houses.

So eventually we'll move away. But until we do, and the reality is, it's not going to happen in my lifetime, so until we do, we better have a way to make that work. And the thing that's really allowed us to do that in the last few years is fracking. And fracking is a fascinating physics problem. It's just an amazingly good physics problem.

So I've been working on that, really having a lot of fun trying to understand the physics of that. It's a fascinating problem. And I think it's of incredible importance because if we can do it better, safer, more efficiently, it makes a big difference, and it's going to be done. No matter what we say, it has to be done. And why I know it makes the differences is, do you know some time, I think about eight or nine months ago, long before the pandemic, before that was important, do you know that Iran attacked the oil fields in Saudi Arabia?

Zierler:

Right.

Weitz:

And cut the oil production by 50 percent in Saudi Arabia.

Zierler:

Right. Right.

Weitz:

Did you notice the difference?

Zierler:

No. In 1977 that would have had a huge impact, huge.

Weitz:

Exactly. Has zero impact, has zero impact. And that's because of fracking. And so I think that's of incredible importance. The fact that geopolitics has changed completely.

Zierler:

Yeah.

Weitz:

And that's not recognized, but to me it's really important.

Zierler:

Sure.

Weitz:

And so if we do that better, I think it's important and boy is it fun to do. It's a really good problem.

Zierler:

I should just share with: you my master's thesis was on the Soviet-American rivalry, the way that they engaged during the Yom Kippur War. And I was very fascinated how Nixon came up with this idea called Project Independence as a result of the Arab oil embargo, which, of course, came about because they felt that they needed to support the Israelis during the war. So I'm very well aware of what the energy situation was in the 1970s.

Weitz:

Right. And it hasn't changed. And, you know, Europe can say no to fracking. But what happens when Putin decides to turn off the gas?

Zierler:

Yeah. And your ongoing interest in fracking suggests that there still lots to be improved, lots to learn about how fracking is done.

Weitz:

I think so. And again, we’re doing very fundamentals, we are not going to be doing the stuff that impacts the field. That's going to have to be done by the oil companies. But I think there's a lot of the fundamentals of fracking, or hydro fracking just fascinating.

Zierler:

Well, Dave, at this point in the discussion, we've, you know, we've touched on everything up to the present day. I want to ask for the last part of our talk, a few broadly retrospective questions about your career and then maybe something more forward looking, thinking about the future.

So the first is, you know, it's obvious the diversity in your research agenda since the beginning of your professional career. It's really quite remarkable, right? And it begins even with this idea that you're beginning your career in a field that is by definition sort of poorly defined and multidisciplinary.

So I wonder, you know, instead of trying to pigeonhole you into telling me what you think your greatest contributions are, I think the more telling question here would be: what do you see as the through line that connects either the kinds of projects that you've been engaged in over the course of your career or your motivation to pour your energy into any given one project, given that there's only so much time and so much money to spend on any one given thing? What are those through lines that connect all of your research?

Weitz:

I'll tell you. It's sort of easy. What I learned at Exxon was there was a place you didn't have tenure and so you had to produce, really produce, or you lost your job. So many times I thought I was six months to losing my job. And, so, how did I do that? What I learned was that if you did something, they still wanted, in the middle might be my time, they wanted to have academic impact, but it also had to have an impact on industry, on Exxon. Exxon is basically a banking company. The way you're going to have impact is discovering new oil. Science and technology have a very low impact.

So what I realized, it was taught to me by one of my colleagues or he helped formulate this one. What I realized was that I could come here and I could say, oh, look at this really cool new science I published in Physical Review Letters, it's really exciting. They say that's fantastic. The next year, they say, well, OK, why is that science good for the company? And they look me up and I'm not doing that anymore, I'm doing something different.

So as long as you kept changing very regularly, you always stayed ahead of the game. You never had to find why it had an impact, you could just keep doing science.

Zierler:

Right.

Weitz:

So I learned the joy. And then I learned how much fun it is to try and do something new, how exciting it is. I remember one of the postdocs there, who worked with Dudley Herschbach. He told me; you know what's good about doing something new? You never make a mistake because you don't know, you know so little you don't realize you're wrong.

Zierler:

[Laughs]

Weitz:

That's what's so much fun. So I learned to really love doing new things. And when you do, when you work in a company where you're trying to define something, you also learn not to ask: is it physics? Is it chemistry? Just ask: is it interesting, is an impactful?

Zierler:

Yeah.

Weitz:

And then, so I'm not afraid to do things that I know nothing about. I'm not afraid to do things in a different field. And then I ask myself, what I want to do in my life? And I just want to do things that have impact, that make a difference to the world. And, you know, it could be, I don't care what the difference is. If it helps health, if it establishes a new company, if it's something that's interesting in science? Ideally, all of them. But I want to do something that makes a difference, that's somehow important.

So I think that to me is how I define it, is I am not afraid to do anything. So nothing, I'm not afraid of anything. Always interested in new things and I don't, you know, so I have no focus. But to me, I'm just not constrained. Anything that's interesting and can have an impact. That somehow seems important and something I can make a difference in. That's what I want to do. And I don't ever want to keep doing the same thing because then the impact will go down and the fun for me goes down. You know, I just love learning something new.

Zierler:

I want to ask a question that will give, I think, a great deal of insight into what really soft matter physics is. And I'll ask it like this. When I talk to people in cosmology or in particle physics, it's very easy to gain a sense of what was understood or not understood 40 or 50 years ago. And what the frontier of knowledge is today is because it's very easy to understand, like, you know, what's it going to take to understand dark matter or what's the next particle to discover, right? But I don't feel like I have a good handle on soft matter physics in terms of, you know, what wasn't understood 30 or 40 years ago that is now really understood or what are the real frontiers of knowledge in soft matter physics? And I wonder if you can sort of help fill in that gap in my knowledge and I suspect a lot of other people's.

Weitz:

Okay, I'm not sure I can do that in as good of a way as you want, because I have a different perspective on that. And it comes, a good way of saying this, is that I think it was, for all condensed matter physics that there was a meeting in Aspen or something, maybe ten or fifteen years ago. At a time where one of the late-night shows where there's a list of 10 things, one of the guys always had a list of 10 things. And so we were going to try and come up with a list of the ten most important problems in condensed matter physics. And we couldn't. We came up with eleven. We couldn't get it down to ten. And so to me the wealth, the richness of a field like soft matter is that it's not dictated by a couple of big problems.

And I think that more traditional solid-state physics for a long time, I felt that way even when I graduated, this was 40 years ago, was dictated by one or two ideas. These are the big problems. Everybody rushes off to work on them. Everybody works on the same thing. And that says, I know what the big problems are, but it's really, it makes the field barren. It makes it dull. It makes it not exciting because everybody is working on the same thing.

Soft matter is really a field that is just so much around us, it's everything. So there aren't that many really big problems. Every once in a while. And people say, well, active soft matter is big. But to me, that's not, it's just because they don't know what to do to. The good things about soft matter is that there's so many problems. So many interesting things that we don't understand of the world around us, of the world that we interact with, that there aren't these well-defined big problems. Instead, there's lots of interesting, smaller problems that will leave room everywhere, leave room for some new ideas to come along. Oh, that's really cool. But then it doesn't dominate the field.

So, I see soft matter as the study of the world around us. And look, we've known the world around us for a long time, right? So I can say, I don't know, you want to study, I was just talking today about micro-emulsions. That's an old topic, it was one of the early topics. People knew micro-emulsions, but people don't know really how to think about them from a real quantitative, physical point of view. They didn't understand the physics of them. So that's where things could be worked out.

So there's a lot of really good physics that we can understand by understanding the physics of things around us. Where the basic ideas are known, but the real underlying physics is still to be uncovered. And when we understand that, then it opens the door to new things, taking new directions to understand new things. So I say that there are not these overriding problems.

I can tell you a million things that we've done that are really important. Like if I work with a company like BASF or any of these sorts of industries like that. They're really well-established industries. But everything's so well well-known that if they want to take something to the next level, they have to find a new S curve to go up. You know what an S curve is?

Zierler:

Yeah.

Weitz:

They have to find a new way of understanding things. And that's what soft matter can help, that's understanding the physics of what they're doing. It will help them take it to a different level. So it's not these massively big problems, it's a myriad of somewhat smaller problems. All of which are fascinating, all which are interesting, and none of which dominate the field, which makes the field that much richer, instead of making it a very dry field because there's a whole bunch of people working on the same topic.

Zierler:

Well, Dave, I think for the last question, I know the thrust of where this is going, because you've already emphasized, you know, what motivates you to continue doing new things. And still, I want to ask, you know, for the future, it seems like so much of your work right now is focusing on biomedical and bioengineering things. And I wonder, you know, the ongoing struggle of always determining what's most important and impactful for you to work on, if in the future you really see things that have that impact on human health, if that's what you see as a priority for them for the remainder of your career.

Weitz:

No. I mean, I think if you've probably figured out that my career has been very mixed and so I want that to be part of it. And I'd really like, at the end of my career, I'd like to be able to look back and say I really had an impact. That I've made a difference in human health. I think I can show you places where it's happening. I'd love to see it happen more. But it's one thing that I want to do. But I don't want to do that exclusively. So I don't see the work that I'm doing on fracking having the same impact on technology, because it's so much harder to have impact on that technology. But I think if we can have some impact, then we learn a lot of physics and be happy there.

And I would love to see, I always am looking for that one experiment which establishes a new scientific field. And if I could do that, I would do it. I never predicted in advance when I do that. I think there's been times when I've done that and I'd like to do that. So it's not just human health. I think in the earlier part of my career, it didn't have any potential impact on human health so I couldn't think about that. Now it does, so I think about that. But it's not just that. It's science. It's society. It's physics in general that I want to impact.

Zierler:

Dave, it's been a delight talking with you today. And I really want to thank you for the time you've spent with me.

Weitz:

Well, thanks a lot. Thanks for doing this.

Zierler:

It's my pleasure.