But let me again come back again to this Ph.D. thesis. Kastler was reassuring because he told me I will get a job, but I was nowhere. I was completely nowhere. And the great concern I had at that time in terms of a career, in terms of where I could be staying, was, in a way, to establish contact with two people I admired above all, because I thought they had succeeded in that search. They were Norbert Wiener and John Von Neumann. So as a post-doc, after I left Phillips I went first to MIT for about half a year and then to Princeton for a year, with Wiener and Von Neumann respectively. Now what attracted me to both is that they both, especially Von Neumann, had this very strong feeling for practical things. He was building his computer. He was not just a person who told other guys to build a computer. He was always about details, "How are you going to do this? Which kind of gadget are you going to use for memory?" He was extraordinarily precise in these matters. At the same time he had written a book on the foundation of quantum mechanics, which I read with terror but great interest. He had written this book about games theory, which looked then extremely promising but of course was just the beginning. He had done this work about logic. I mean, in a way Von Neumann was the person who had performed the miracle. He was for me the model above all models. But before that I went to Princeton, I went to MIT, to work with Wiener. Wiener was a sort of a flop. Wiener was by then too old, too removed; one couldn't communicate with him usefully, and everybody at MIT was pushing him around. I felt Wiener was a terrifying counter example - that even a man who achieved such great work as making a theory of Brownian motion, not as a mathematical idea but as something dirty and incomprehensible from which one must extract the mathematical essentials, that this man was not respected by anybody, neither by mathematicians nor any longer by the engineers, but Von Neumann was. Perhaps I should start by jumping ahead because it is an important fact. Much later, I was to find that my view of Von Neumann as a great man was completely confirmed. My view of Von Neumann as a successful person in a sense of being, how to say, accepted by the community for what he was, was totally wrong. Von Neumann, when I was there at Princeton, was under extreme pressure from mathematicians who were despising him for no longer being a mathematician; by the physicists who were despising him for never having been a real physicist; and by everybody for having brought to Princeton this collection of low-class individuals called programmers, who were just not the kind of people that Princeton liked to have on staff; and of having all those engineers, all those people in uniform coming to look at that- Von Neumann was simply being shunned. And he was not a man to take it. So even before I left Princeton, he had resigned from Princeton and accepted a position, which I can testify was well accepted, as a staff member in the Institute of Earth and Planetary Physics at UCLA, together with a very high-sounding Professorship at Large at the University of California. But he was not interested in the Professorship at Large at the University of California; what he wanted was a place where people really needed a computer, were prepared to do everything to make a computer, and were interested in real things, for example, space and planetary studies, because that was the frontier for him. Economics, planetary stuff, flight, and nothing else, so he didn't need the Princeton Institute on his calling cards at all and he accepted it. But I didn't know it.
Benoît Mandelbrot (1924-2010) discovered his ability to think about mathematics in images while working with the French Resistance during the Second World War, and is famous for his work on fractal geometry - the maths of the shapes found in nature.
Title: Post-doctoral studies: Weiner and Von Neumann
Listeners:
Daniel Zajdenweber
Bernard Sapoval
Daniel Zajdenweber is a Professor at the College of Economics, University of Paris.
Bernard Sapoval is Research Director at C.N.R.S. Since 1983 his work has focused on the physics of fractals and irregular systems and structures and properties in general. The main themes are the fractal structure of diffusion fronts, the concept of percolation in a gradient, random walks in a probability gradient as a method to calculate the threshold of percolation in two dimensions, the concept of intercalation and invasion noise, observed, for example, in the absorbance of a liquid in a porous substance, prediction of the fractal dimension of certain corrosion figures, the possibility of increasing sharpness in fuzzy images by a numerical analysis using the concept of percolation in a gradient, calculation of the way a fractal model will respond to external stimulus and the correspondence between the electrochemical response of an irregular electrode and the absorbance of a membrane of the same geometry.
Duration:
4 minutes, 45 seconds
Date story recorded:
May 1998
Date story went live:
24 January 2008