“All good intellects have repeated, since Bacon’s time, that there can be no real knowledge but which is based on observed facts.”

Language forms a kind of wealth, which all can make use of at once without causing any diminution of the store, and which thus admits a complete community of enjoyment; for all, freely participating in the general treasure, unconsciously aid in its preservation.

The only real life is the collective life of the race; individual life has no existence except as an abstraction.

To understand a science it is necessary to know its history.

To reorganize society without God or King, by the systematic culture of Humanity.

The heavens declare the glory of Kepler and Newton.

Each department of knowledge passes through three stages. The theoretic stage; the theological stage and the metaphysical or abstract stage.

In mathematics we find the primitive source of rationality; and to mathematics must the biologists resort for means to carry out their researches.

The sacred formula of positivism: love as a principle, the order as a foundation, and progress as a goal.

Monotheism occupies so large a space in the view of modern minds, that it is scarcely possible to form a just estimate of the preceding phases of the theological philosophy.

Religion is an illusion of childhood, outgrown under proper education.

If we do not allow free thinking in chemistry or biology, why should we allow it in morals or politics?

Mathematical Analysis is… the true rational basis of the whole system of our positive knowledge.

Nothing is destroyed until it is replaced.

The dead govern the living.

Woman is the most moral element in all humanity.

The word right should be excluded from political language, as the word cause from the language of philosophy.