The only ethical principle which has made science possible is that the truth shall be told all the time. If we do not penalize false statements made in error, we open up the way for false statements by intention. And a false statement of fact, made deliberately, is the most serious crime a scientist can commit.
[I]t's difficult to make people see that what you have been taught counts for nothing, and that the only things worth having are the things you find out for yourself. Also, that when so many brands of what Chesterton calls 'fancy souls' and theories of life are offered you, there is no sense in not looking pretty carefully to see what you are going in for. [...] It isn't a case of 'Here is the Christian religion, the one authoritative and respectable rule of life. Take it or leave it'. It's 'Here's a muddling kind of affair called Life, and here are nineteen or twenty different explanations of it, all supported by people whose opinions are not to be sneezed at. Among them is the Christian religion in which you happpen to have been brought up. Your friend so-and-so has been brought up in quite a different way of thinking; is a perfectly splendid person and thoroughly happy. What are you going to do about it?' -- I'm worrying it out quietly, and whatever I get hold of will be valuable, because I've got it for myself; but really, you know, the whole question is not as simple as it looks.