We shall say that we have acquaintance with anything of which we are directly aware, without the intermediary of any process of inference of any knowledge of truths.

Worry is a form of fear, and all forms of fear produce fatigue. A man who has learned not to feel fear will find the fatigue of daily life enormously diminished.

Indemnity for the past and security for the future.

To modern educated people, it seems obvious that matters of fact are to be ascertained by observation, not by consulting ancient authorities. But this is an entirely modern conception, which hardly existed before the seventeenth century.

Only mathematics and mathematical logic can say as little as the physicist means to say.

Those who advocate common usage in philosophy sometimes speak in a manner that suggests the mystique of the 'common man.'

Dogma demands authority, rather than intelligent thought, as the source of opinion; it requires persecution of heretics and hostility to unbelievers; it asks of its disciples that they should inhibit natural kindliness in favor of systematic hatred.