Time, matter, space - all, it may be, are no more than a point.

If there were a reason for preferring the Christian religion to natural religion, it would be because the former offers us, on the nature of God and man, enlightenment that the latter lacks. Now, this is not at all the case; for Christianity, instead of clarifying, gives rise to an infinite multitude of obscurities and difficulties.

Scepticism is the first step toward truth.

The most dangerous madmen are those created by religion, and people whose aim is to disrupt society always know how to make good use of them on occasion.

The philosopher forms his principles on an infinity of particular observations. He does not confuse truth with plausibility, he takes for truth what is true, for false what is false, for doubtful what is doubtful, and probable what is probable. The philosophical spirit is thus a spirit of observation and accuracy.

Isn't it better to have men being ungrateful than to miss a chance to do good?

One must be oneself very little of a philosopher not to feel that the finest privilege of our reason consists in not believing in anything by the impulsion of a blind and mechanical instinct, and that it is to dishonour reason to put it in bonds as the Chaldeans did. Man is born to think for himself.