Men often act knowingly against their interest.

Any person seasoned with a just sense of the imperfections of natural reason, will fly to revealed truth with the greatest avidity.

I am apt to suspect the Negroes to be naturally inferior to the Whites. There scarcely ever was a civilization of their complexion, nor even any individual, eminent either in action or speculation.

There has been a controversy started of late, much better worth examination, concerning the general foundation of Morals; whether they be derived from Reason, or from Sentiment; whether we attain the knowledge of them by a chain of argument and induction, or by an immediate feeling and finer internal sense; whether, like all sound judgement of truth and falsehood, they should be the same to every rational intelligent being; or whether, like the perception of beauty and deformity, they be founded entirely on the particular fabric and constitution of the human species.

The Crusades - the most signal and most durable monument of human folly that has yet appeared in any age or nation.

It is not contrary to reason to prefer the destruction of the whole world to the scratching of my finger. It is not contrary to reason for me to choose my total ruin, to prevent the least uneasiness of an Indian, or person wholly unknown to me. It is as little contrary to reason to prefer even my own acknowledged lesser good to my greater, and have a more ardent affection for the former than the latter.

..when, in my philosophical disquisitions, I deny a providence and a future state, I undermine not the foundations of society, but advance principles, which they themselves, upon their own topics, if they argue consistently, must allow to be solid and satisfactory.