Science, in its ultimate ideal, consists of a set of propositions arranged in a hierarchy, the lowest level of the hierarchy being concerned with particular facts, and the highest with some general law, governing everything in the universe. The various levels in the hierarchy have a two-fold logical connection, travelling one up, one down; the upward connection proceeds by induction, the downward by deduction.

There are two ways of avoiding fear: one is by persuading ourselves that we are immune from disaster, and the other is by the practice of sheer courage. The latter is difficult, and to everybody becomes impossible at a certain point. The former has therefore always been more popular. Primitive magic has the purpose of securing safety, either by injuring enemies, or by protecting oneself by talismans, spells, or incantations.

The wise use of leisure, it must be conceded, is a product of civilization and education.

A word is used "correctly" when the average hearer will be affected by it in the way intended. This is a psychological, not a literary, definition of "correctness". The literary definition would substitute, for the average hearer, a person of high education living a long time ago; the purpose of this definition is to make it difficult to speak or write correctly.

Force plays a much larger part in the government of the world than it did before 1914, and what is especially alarming, force tends increasingly to fall into the hands of those who are enemies of civilization.

The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd.

An extra-terrestrial philosopher, who had watched a single youth up to the age of twenty-one and had never come across any other human being, might conclude that it is the nature of human beings to grow continually taller and wiser in an indefinite progress towards perfection; and this generalization would be just as well founded as the generalization which evolutionists base upon the previous history of this planet.