It is not what we believe, but why we believe it. Moral responsibility lies in diligently weighing the evidence. We must actively doubt; we have to scrutinize our views, not take them on trust. No virtue attached to blindly accepting orthodoxy, however 'venerable'.

The only medicine for suffering, crime, and all other woes of mankind, is wisdom. Teach a man to read and write, and you have put into his hands the great keys of the wisdom box. But it is quite another thing to open the box.

Try to learn something about everything and everything about something.

What men of science want is only a fair day's wages for more than a fair day's work.

If every man possessed everything he wanted, and no one had the power to interfere with such possession; or if no man desired thatwhich could damage his fellow-man, justice would have no part to play in the universe.

It is because the body is a machine that education is possible. Education is the formation of habits, a superinducing of an artificial organization upon the natural organization of the body.

The ultimate court of appeal is observation and experiment... not authority.