There is no logical impossibility in the hypothesis that the world sprang into being five minutes ago, exactly as it then was, with a population that… - Bertrand Russell

A life without adventure is likely to be unsatisfying, but a life in which adventure is allowed to take whatever form it will is sure to be short.

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 field of mathematics, with more solid foundations than those that had hitherto been 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.

The world at present is obsessed by the conflict of rival ideologies, and one of the apparent causes of conflict is the desire for the victory of our own ideology and the defeat of the other. I do not think that the fundamental motive here has much to do with ideologies. I think the ideologies are merely a way of grouping people, and that the passions involved are merely those which always arise between rival groups. Ideologies, in fact, are one of the methods by which herds are created, and the psychology is much the same however the herd may have been generated.