_Question returns._--Among these several views, where then, lies the truth? Unable to coincide with the merely mechanical theory of Descartes, or with the view which resolves all into mere habit and association, with Locke and Condillac, shall we fall back upon the ancient, and for a long time universally prevalent, view which makes instinct only a lower degree of that intelligence which, in man becomes reason and reflection? This we are hardly prepared to do. The well-known phenomena and laws of instinct, its essential characteristics as developed in the preceding pages, seem to point to a difference in kind and not merely in degree. _Reasons for this Opinion._--_1. The Brute incapable of high Cultivation._--To recapitulate briefly the points of difference: If instinct in the brute were of the same nature with intelligence in man, if it were, properly speaking, _intelligence_, the same in kind, differing only in degree, then, it ought, as in man, to be capable of cultivation to an indefinite extent, capable of being elevated, by due process of training, to a degree very much superior to that in which it first presents itself. Now, with certain insignificant exceptions, such is certainly not the case. No amount of training or culture ever brings the animal essentially above the ordinary range of brute capacity, or approximates him to the level of the human species. _2. Brute does not improve by Practice._--On this theory the brute ought, moreover, to improve by practice, which, for the most part, certainly he does not. The spider lays out its lines as accurately and constructs its web as well, and the bee her comb, and the bird her nest, on the first attempt, as after the twentieth or the fiftieth trial. There is no progress, no improvement. Its skill, if such it may be called, is a fixture. There is nothing of the nature of _science_ about it, for it is of the essential nature of all intelligent action to improve. _3. Does not adapt itself to Circumstances._--If it were of the nature of intelligence, it ought uniformly and invariably to adapt itself to changing circumstances, and not to keep on working blindly in the old way, when such procedure is no longer of use. It is not intelligence, but mere blind impulse, in the beaver, that leads him to build his dam on a dry floor or the pavement of a court-yard.