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.

Superstition is more injurious to God than atheism.

The enjoyment of freedom which could be exercised without any motivation would be the real hallmark of a maniac.

Instinct guides the animal better than the man. In the animal it is pure, in man it is led astray by his reason and intelligence.

Fanaticism is just one step away from barbarism.

As long as the centuries continue to unfold, the number of books will grow continually, and one can predict that a time will come when it will be almost as difficult to learn anything from books as from the direct study of the whole universe. It will be almost as convenient to search for some bit of truth concealed in nature as it will be to find it hidden away in an immense multitude of bound volumes.

I feel, I think, I judge; therefore, a part of organized matter like me is capable of feeling, thinking, and judging.