"Weinberg had a remarkable feel for the workings of nature. Always beginning with experimentally well-established principles, he had an uncanny ability to set out regularities in the natural world and to use them to account for a wide range of measurements and observations. He loved mathematics, he told me, but it was only ever a tool for him: more than anything else, he wanted ‘to explain the world’, a phrase he used as the title of one of his popular books. In many ways, his approach was similar to that of Richard Feynman, and for many years I was puzzled by the many rumours I heard that they did not get on. Weinberg confirmed to me only relatively recently that the stories were true. ‘I didn’t like [Feynman] very much’, he admitted. The main reason was that whenever Weinberg gave a talk at Caltech, Feynman harried him mercilessly, to the point of cruelty. Several witnesses to these encounters told me that Feynman appeared to be jealous of Weinberg’s ascent to pre-eminence and could never resist trying to take him down a peg or two. Feynman’s brilliant colleague Murray Gell-Mann, also famous for his aggression, was a much more reasonable critic, Weinberg said: ‘If you set out a good argument, in a bullet-proof way, Murray would leave you alone’."