As a rule philosophers, psychologists, and theologians, have replied in the negative, and naturalists in the affirmative. This opposition can be easily understood. The former make the human mind, considered as an indivisible whole, their principal study, and attribute to it all our faculties. Unable to deny the similarity, external at least, between certain animal and human acts, and yet being anxious to clearly distinguish man from the brute, they have given to the acts different interpretations as they have been performed by one or the other. Naturalists have regarded the phenomena more closely without thinking of anything else, and when they have seen the animal behave in the same manner as they themselves would have done under the given circumstances, they have concluded that the motives of the action must be fundamentally the same. I must ask permission to remain a naturalist, and to recall some facts, and regard them from this point of view. The theologians themselves allow that the animal possesses sensation, formation and association of images, imagination, and passion (R. P. de Bonniot). They allow that the animal feels the relation of fitness or of unfitness between sensible objects and his own senses; that it experiences sensible attractions and repulsions, and acts perfectly in consequence, and that _in this sense the animal reasons and judges_ (l’Abbé A. Lecomte). Therefore, they add, we cannot doubt but that the animal possesses a principle superior to that of mere matter, and we may even give it the name of mind (R. P. Bonniot). But in spite of all, theologians and philosophers maintain that the animal cannot be intelligent, because it has neither _innate sense_, _consciousness_ nor _reason_. Let us leave for a moment the last term, with which the idea of phenomena which we shall presently discuss, is connected in the mind of our opponents. Is it true that animals are wanting in innate sense, and are not conscious of their actions? Upon what facts of observation does this opinion rest? We each one of us feel that we possess this sense, that we enjoy this faculty. By means of speech we can convey to another the results of our personal experience. But this source of information is wanting when we come to deal with animals. Neither in them nor in ourselves are innate sense and consciousness revealed to the outer world by any special characteristic movement. It is, therefore, only by interpreting these movements, and by judging from ourselves, that we can form an idea of the motives from which the animal acts.