Einstein admits that he will probably not live to see the resolution of a stubborn problem in physics.

Einstein modestly deflects praise from his old friend, who has described him as a 'focal point in this confused world', referring to this as 'your flattering remark on my miserable person', and remembering a similar declaration by his old Viennese colleague Paul Ehrenhaft. Besso's remark on the generalised theory of relativity is correct: 'As to the rationality of this theory, there is no doubt. But so far nothing speaks for its accuracy. This comes from the fact that the theory must limit itself to solutions which are everywhere free of singularities', and untangling the existence of these solutions goes beyond the power of current mathematics: 'So we will probably not live to see the verdict'. Einstein gently chides his friend for suggesting that the theory is connected with the irreversibility of the laws of nature – he has already explained his grounds for disbelieving this.