History of Western Philosophy - Bertrand Russell [345]
A characteristic of Locke, which descended from him to the whole Liberal movement, is lack of dogmatism. Some few certainties he takes over from his predecessors: our own existence, the existence of God, and the truth of mathematics. But wherever his doctrines differ from those of his forerunners, they are to the effect that truth is hard to ascertain, and that a rational man will hold his opinions with some measure of doubt. This temper of mind is obviously connected with religious toleration, with the success of parliamentary democracy, with laissez-faire, and with the whole system of liberal maxims. Although he is a deeply religious man, a devout believer in Christianity who accepts revelation as a source of knowledge, he nevertheless hedges round professed revelations with rational safeguards. On one occasion he says: 'The bare testimony of revelation is the highest certainty,' but on another he says: 'Revelation must be judged by reason.' Thus in the end reason remains supreme.
His chapter 'Of Enthusiasm' is instructive in this connection. 'Enthusiasm' had not then the same meaning as it has now; it meant the belief in a personal revelation to a religious leader or to his followers. It was a characteristic of the sects that had been defeated at the Restoration. When there is a multiplicity of such personal revelations, all inconsistent with each other, truth, or what passes as such, becomes purely personal, and loses its social character. Love of truth, which Locke considers essential, is a very different thing from love of some particular doctrine which is proclaimed as the truth. One unerring mark of love of truth, he says, is 'not entertaining any proposition with greater assurance than the proofs it is built upon will warrant'. Forwardness to dictate, he says, shows failure of love of truth. 'Enthusiasm laying by reason, would set up revelation without it; whereby in effect it takes away both reason and revelation, and substitutes in the room of it the ungrounded fancies of a man's own brain.' Men who suffer from melancholy or conceit are likely to have 'persuasions of immediate intercourse with the Deity'. Hence odd actions and opinions acquire Divine sanction, which flatters 'men's laziness, ignorance, and vanity'. He concludes the chapter with the maxim already quoted, that 'revelation must be judged of by reason'.
What Locke means by 'reason' is to be gathered from his whole book. There is, it is true, a chapter called 'Of Reason', but this is mainly concerned to prove that reason does not consist of syllogistic reasoning, and is summed up in the sentence: 'God has not been so sparing to men to make them barely two-legged creatures, and left it to Aristotle to make them rational.' Reason, as Locke uses the term, consists of two parts: first, an inquiry as to what things we know with certainty; second, an investigation of propositions which it is wise to accept in practice, although they have only probability and not certainty in their favour. 'The grounds of probability,' he says, 'are two: conformity with our own experience, or the testimony of others' experience.' The King of Siam, he remarks, ceased to believe what Europeans told him when they mentioned ice.
In his chapter 'Of Degrees of Assent' he says that the degree of assent we give to any proposition should depend upon the grounds of probability in its favour. After pointing out that we must often act upon probabilities that fall short of certainty, he says that the right use of this consideration 'is mutual charity and forbearance. Since therefore it is unavoidable to the greatest part of men, if not all, to have several opinions, without certain and indubitable proofs of their truth; and it carries too great an imputation of ignorance, lightness,