The doctrine of transmigration… was a means of constructing a plausible vindication of the ways of the cosmos to man; … none but very hasty thinkers will reject it on the grounds of inherent absurdity.

We are prone to see what lies behind our eyes, rather than what apprears before them.

My experience of the world is that things left to themselves don't get right.

The dogma of the infallibility of the Bible is no more self-evident than is that of the infallibility of the popes.

We live in a world which is full of misery and ignorance, and the plain duty of each and all of us is to try to make the little corner he can influence somewhat less miserable and somewhat less ignorant than it was before he entered.

It is one of the most saddening things in life that, try as we may, we can never be certain of making people happy, whereas we can almost always be certain of making them unhappy.

The great tragedy of science - the slaying of a beautiful hypothesis by an ugly fact.