ABSTRACT
On reaching the age of eighty it is reasonable to suppose that the bulk of one’s work is done, and that what remains to do will be of less importance. The serious part of my life ever since boyhood has been devoted to two different objects which for a long time remained separate and have only in recent years united into a single whole. I wanted, on the one hand, to find out whether anything could be known; and, on the other hand, to do whatever might be possible towards creating a happier world. Up to the age of thirty-eight I gave most of my energies to the first of these tasks. I was troubled by scepticism and unwillingly forced to the conclusion that most of what passes for knowledge is open to reasonable doubt. I wanted certainty in the kind of way in which people want religious faith. I thought that certainty is more likely to be found in mathematics than elsewhere. But I discovered that many mathematical demonstrations, which my teachers expected me to accept, were full of fallacies, and that, if certainty were indeed discoverable in mathematics, it would be in a new kind of mathematics, with more solid foundations than those that had hitherto 46been thought secure. But as the work proceeded, I was continually reminded of the fable about the elephant and the tortoise. Having constructed an elephant upon which the mathematical world could rest, I found the elephant tottering, and proceeded to construct a tortoise to keep the elephant from falling. But the tortoise was no more secure than the elephant, and after some twenty years of very arduous toil, I came to the conclusion that there was nothing more that I could do in the way of making mathematical knowledge indubitable. Then came the First World War, and my thoughts became concentrated on human misery and folly. Neither misery nor folly seems to me any part of the inevitable lot of man. And I am convinced that intelligence, patience, and eloquence can, sooner or later, lead the human race out of its self-imposed tortures provided it does not exterminate itself meanwhile.
