Absolute materialists may make light of this difficulty, and may hold that this would imply merely a change of brain; but even if we admit this, they fail to show of what use such better brain would be to a creature retaining the bodily form and instincts of the ape, or how such better brain could be acquired. But evolutionists are not necessarily absolute materialists, and Darwin himself labours to show that the reasoning self-conscious mind, and even the moral sentiments of man, might be evolved from rudiments of such powers, perceptible in the lower animals. Here, however, he leaves the court of natural science, properly so called, and summons us to appear before the judgment-seat of philosophy; and as naturalists are often bad mental philosophers, and philosophers have often small knowledge of nature, some advantage results, in the first instance, to the doubtful cause of evolution. Since, however, mental science makes much more of the distinctions between the mind of man and the instinct of animals then naturalists, accustomed to deal merely with the external organism, can be expected to do, the derivationist, when his plea is fairly understood, is quite as certain to lose his cause as when tried by geology and zoology. He might indeed be left to be dealt with by mental science on its own ground; and as our province is to look at the matter from the standpoint of natural history, we might here close our inquiry. It may, however, be proper to give some slight notion of the width of the gulf to be passed when we suppose the mechanical, unconscious, repetitive nature of the animal to pass over into the condition of an intellectual and moral being.