I wish to propose for the reader's favourable consideration a doctrine which may, I fear, appear wildly paradoxical and subversive. The doctrine in question is this: that it is undesirable to believe a proposition when there is no ground whatever for supposing it true. I must of course admit that if such an opinion became common it would completely transform our social life and our political system; since both are at present faultless, this must weigh against it. — Bertrand Russell [Sceptical Essays]