What is repugnant to every human being is to be reckoned always as a member of a class and not as an individual person.

Have you noticed that the astronomers and mathematicians are much the most cheerful people of the lot? I suppose that perpetually contemplating things on so vast a scale makes them feel either that it doesn't matter a hoot anyway, or that anything so large and elaborate must have some sense in it somewhere.

But that's men all over ... Poor dears, they can't help it. They haven't got logical minds.

Of course, there is some truth in advertising. There's yeast in bread, but you can't make bread with yeast alone. Truth in advertising is like leaven, which a woman hid in three measures of meal. It provides a suitable quantity of gas, with which to blow out a mass of crude misrepresentation into a form that the public can swallow.

I have never yet heard any middle-aged man or woman who worked with his or her brains express any regret for the passing of youth.

Very dangerous things, theories.

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.