Science is simply common sense at its best.

No man is any the worse off because another acquires wealth by trade, or by the exercise of a profession; on the contrary, he cannot have acquired his wealth except by benefiting others to the extent of what they considered to be its value.

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.

The only question which any wise man can ask himself, and which any honest man will ask himself, is whether a doctrine is true or false.

The clergy are at present divided into three sections: an immense body who are ignorant; a small proportion who know and are silent; and a minute minority who know and speak according to their knowledge.

Education is the instruction of the intellect in the laws of Nature.

Give unqualified assent to no propositions but those the truth of which is so clear and distinct that they cannot be doubted. The enunciation of this first great commandment of science consecrated doubt.