Humanistic ethics is based on the principle that only humans themselves can determine the criterion for virtue and not an authority transcending us.

To modern educated people, it seems obvious that matters of fact are to be ascertained by observation, not by consulting ancient authorities. But this is an entirely modern conception, which hardly existed before the seventeenth century.

I had supposed until that time that it was quite common for parents to love their children, but the war persuaded me that it is a rare exception. I had supposed that most people liked money better than almost anything else, but I discovered that they liked destruction even better. I had supposed that intellectuals frequently loved truth, but I found here again that not ten per cent of them prefer truth to popularity.

Intelligence, it might be said, has caused our troubles; but it is not unintelligence that will cure them. Only more and wiser intelligence can make a happier world

There are three ways of securing a society that shall be stable as regards population. The first is that of birth control, the second that of infanticide or really destructive wars, and the third that of general misery except for a powerful minority.

When it was first proposed to establish laboratories at Cambridge, Todhunter, the mathematician, objected that it was unnecessary for students to see experiments performed, since the results could be vouched for by their teachers, all of them of the highest character, and many of them clergymen of the Church of England.

All human activity is prompted by desire.