A Controversy about the Quantization of Gravity and the Quantum Measurement Process (1962–1965)

By Thiago Hartz

Universidade Federal da Bahia


The quantization of gravity has been the subject of many debates during the last eighty years. In this work I will discuss a controversy about this subject that began during a conference occurred in Poland in 1962 and that endured to 1965.

In this conference, Bryce DeWitt presented a seminar where he showed that the gravitational field must necessarily be quantized. In order to support his reasoning he used many arguments from the famous Bohr and Rosenfeld's article published in 1933. There was no intention of showing the necessity of quantization in the 1933 article and DeWitt knew it. He wasn't defending Bohr's ideas, but instead extending them with purposes that went far beyond Bohr's original intentions. Léon Rosenfeld was in the audience, and at the end of the seminar he expressed his disagreement about DeWitt's reasoning. This comment generated some discussion with Frederik Belinfante, but at the end it seems that all physicists kept theirs initial stances. In the next three years several others debates on the necessity of quantization occurred among Rosenfeld, DeWitt, Ernest Henley, Walter Thirring, and Helmut Hönl. These debates were a consequence of a dispute about the uses of Bohr's ideas by the young physicists and Rosenfeld's reaction in defense of Bohr's original intentions.

In this work I will analyze the arguments presented in these discussions. I sustain that the divergences among these physicists concerning the necessity of quantization cannot be understood unless we observe the differences between their conceptions of the quantum measurement process.