Science is uncertain.

'Conservation' (the conservation law) means this ... that there is a number, which you can calculate, at one moment-and as nature undergoes its multitude of changes, this number doesn't change. That is, if you calculate again, this quantity, it'll be the same as it was before. An example is the conservation of energy: there's a quantity that you can calculate according to a certain rule, and it comes out the same answer after, no matter what happens, happens.

[Quantum mechanics] describes nature as absurd from the point of view of common sense. And yet it fully agrees with experiment. So I hope you can accept nature as She is - absurd.

When a Caltech student asked the eminent cosmologist Michael Turner what his "bias" was in favoring one or another particle as a likely candidate to compromise dark matter in the universe, Feynmann snapped, "Why do you want to know his bias? Form your own bias!"

In fact the total amount that a physicist knows is very little. He has only to remember the rules to get him from one place to another and he is all right.

There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time ... On the other hand, I think I can safely say that nobody understands quantum mechanics.

Ordinary fools are all right; you can talk to them, and try to help them out. But pompous fools-guys who are fools and are covering it all over and impressing people as to how wonderful they are with all this hocus pocus-THAT, I CANNOT STAND! An ordinary fool isn't a faker; an honest fool is all right. But a dishonest fool is terrible!