It would strike me as ridiculous to want to doubt the existence of Napoleon; but if someone doubted the existence of the earth 150years ago, perhaps I should be more willing to listen, for now he is doubting our whole system of evidence.

All philosophy is a 'critique of language' (though not in Mauthner's sense). It was Russell who performed the service of showing that the apparent logical form of a proposition need not be its real one.

An image is not a picture, but a picture can correspond to it.

The aspects of a thing that are most important to us are hidden to us because of their simplicity and familiarity.

A propositional sign, applied and thought out, is a thought. A thought is a proposition with a sense.

The common behavior of mankind is the system of reference by means of which we interpret an unknown language.

The logic of the world is prior to all truth and falsehood.