The most dangerous untruths are truths slightly distorted.
The great trick of regarding small departures from the truth as the truth itself - on which is founded the entire integral calculus - is also the basis of our witty speculations, where the whole thing would often collapse if we considered the departures with philosophical rigour.
To see every day how people get the name 'genius' just as the wood-lice in the cellar the name 'millipede'-not because they have that many feet, but because most people don't want to count to 14-this has had the result that I don't believe anyone any more without checking.
One can live in this world on soothsaying but not on truth saying.
