A man's knowledge may be said to be mature, in other words, when it has reached the most complete state of perfection to which he, as an individual, is capable of bringing it, when an exact correspondence is established between the whole of his abstract ideas and the things he has actually perceived for himself. His will mean that each of his abstract ideas rests, directly or indirectly, upon a basis of observation, which alone endows it with any real value; and also that he is able to place every observation he makes under the right abstract idea which belongs to it.

The bad thing about all religions is that, instead of being able to confess their allegorical nature, they have to conceal it.

On the path of actions, great heart is the chief recommendation; on that works, a great head.

For it is a matter of daily observation that people take the greatest pleasure in that which satisfies their vanity; and vanity cannot be satisfied without comparison with others.

Everything that happens, happens of necessity.

Monotheistic religions alone furnish the spectacle of religious wars, religious persecutions, heretical tribunals, that breaking of idols and destruction of images of the gods, that razing of Indian temples and Egyptian colossi, which had looked on the sun 3,000 years: just because a jealous god had said, Thou shalt make no graven image.

In truth the most striking figure for the relation of the two is that of the strong blind man carrying the sighted lame man on his shoulders.