But there are other reasons which recommend the study of educators and the reading of their works. The history of pedagogy is a necessary introduction to pedagogy itself. It should be studied, not for purposes of erudition or for mere curiosity, but with a practical purpose for the sake of finding in it the permanent truths which are the essentials of a definite theory of education. The desirable thing just now is not perhaps so much to find new ideas, as properly to comprehend those which are already current; to choose from among them, and, a choice once having been made, to make a resolute effort to apply them to use. When we consider with impartiality all that has been conceived or practised previous to the nineteenth century, or when we see clearly what our predecessors have left us to do in the way of consequences to deduce, of incomplete or obscure ideas to generalize or to illustrate, and especially of opposing tendencies to reconcile, we may well inquire what they have really left us to discover. It is profitable to study even the chimeras and the educational errors of our predecessors. In fact, these are so many marked experiments which contribute to the progress of our methods by warning us of the rocks which we should shun. A thorough analysis of the paradoxes of Rousseau, and of the absurd consequences to which the abuse of the principle of nature leads us, is no less instructive than meditation on the wisest precepts of Montaigne or of Port Royal. In truth, for him who has an exact knowledge of the educators of past centuries, the work of constructing a system of education is more than half done. It remains only to co-ordinate the scattered truths which have been collected from their works by assimilating them through personal reflection, and by making them fruitful through psychological analysis and moral faith. Let it be observed that as studied by the men who first conceived and practised them, pedagogical methods present themselves to our examination with a sharpness of outline that is surprising. Innovators lend to whatever they invent a personal emphasis, something life-like and occasionally extravagant; but it is exactly this which permits us the better to comprehend their thought, and the more completely to discover its truth or its falsity.