The possession of power inevitably spoils the free use of reason.

The sceptics, a kind of nomads, despising all settled culture of the land, broke up from time to time all civil society. Fortunately their number was small, and they could not prevent the old settlers from returning to cultivate the ground afresh, though without any fixed plan or agreement.

For how is it possible, says that acute man, that when a concept is given me, I can go beyond it and connect with it another which is not contained in it, in such a manner as if that latter necessarily belonged to the former?

All perception is colored by emotion.

In every department of physical science there is only so much science, properly so-called, as there is mathematics.

The bad thing of war is, that it makes more evil people than it can take away.

Thoughts without content are empty, intuitions without concepts are blind.