The inferences that we actually make in daily life differ from those of syllogistic logic in two respects, namely, that they are important and precarious, instead of being trivial and safe. The syllogism may be regarded as a monument to academic timidity: if an inference might be wrong, it was dangerous to draw it. So the mediæval monks, in their thinking as in their lives, sought safety at the expense of fertility. With the Renaissance, a more adventurous spirit came into the world, but at first in philosophy, it only took the form of following Greeks other than Aristotle, and more especially Plato. It is only with Bacon and Galileo that the inductive method arrived at due recognition: with Bacon as a programme which was largely faulty, but with Galileo as something which actually led to brilliant results, namely, the foundation of modern mathematical physics. Unfortunately, when the pedants got hold of induction, they set to work to make it as tame and scholastic as deduction had been. They searched for a way of making it _always_ lead to true results, and in so doing robbed it of its adventurous character. Hume turned upon them with sceptical arguments, proving quite conclusively that if an induction is worth making it may be wrong. Thereupon Kant deluged the philosophic world with muddle and mystery, from which it is only now beginning to emerge. Kant has the reputation of being the greatest of modern philosophers, but to my mind he was a mere misfortune. Induction, as it appears in the text-books, consists, roughly speaking, in the inference that, because A and B have been found often together and never apart, therefore they are probably always together, and either may be taken as a sign of the other. I do not wish, at this stage, to examine the logical justification of this form of argumentation; for the present, I am considering it as a _practice_, which we can observe in the habits of men and animals.