"... Gelfand amazed me by talking of mathematics as if it were poetry. He tried to explain to me what von Neumann had been trying to do and what the ideas were behind his work. That was a revelation for me — that one could talk about mathematics that way. It is not just some abstract and beautiful construction but is driven by the attempt to understand certain basic phenomena that one tries to capture in some idea or theory. If you can’t quite express it one way, you try another. If that doesn’t quite work, you try to get further by some completely different approach. There is a whole undercurrent of ideas and questions."