Since the world is what it is, it is clear that valid reasoning from sound principles cannot lead to error; but a principle may be so nearly true as to deserve theoretical respect, and yet may lead to practical consequences which we feel to be absurd. There is therefore a justification for common sense in philosophy, but only as showing that our theoretical principles cannot be quite correct so long as their consequences are condemned by an appeal to common sense which we feel to be irresistible. The theorist may retort that common sense is no more infallible than logic. But this retort, though made by Berkeley and Hume, would have been wholly foreign to Locke's intellectual temper.

Spinoza (1634-77) is the noblest and most lovable of the great philosophers. Intellectually, some have surpassed him, but ethically he is supreme. As a natural…

The quarrel between Hume and Rousseau is symbolic: Rousseau was mad but influential, Hume was sane but had no followers.

I do not agree with Plato, but if anything could make me do so, it would be Aristotle's arguments against him.

Logician: A cat has four paws. Old Gentleman: My dog had four paws. Logician: Then it's a cat. Old Gentleman: So my dog is a cat? Logician: And the contrary is…

Aristotle... a mere bond-servant to his logic, thereby rendering it contentious and well nigh useless.

Do not imagine that mathematics is hard and crabbed, and repulsive to common sense. It is merely the etherealization of common sense.