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

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.

nd now that man's history has been for the first time systematically considered as a whole, and has been found to be, like all other phenomena, subject to invariable laws, the preparatory labours of modern Science are ended.

Humanity is always made up of more dead than living.

Everything is relative; and only that is absolute.

The law is this: that each of our leading conceptions-each branch of our knowledge-passes successively through three different theoretical conditions: the Theological, or fictitious: the Metaphysical, or abstract; and the Scientific, or positive.

Men are not allowed to think freely about chemistry and biology: why should they be allowed to think freely about political philosophy?