Mathematical Mirror

prehended under memory according to the translation of Aristotle which is in common use. But undoubtedly it is then necessary that memory be twofold and very different, so that one will be the chest of the common sense, and the other of the estimation, and they will be different according to species, and according to subject, and organ, and operation. And since the virtues have already been placed in the brain, it is to be understood that the substance of the brain does not feel, as Avicenna teaches in the 10th [book] of On Animals, and in this he corrects Aristotle with a pious and respectful interpretation. For marrow in other places of the body does not have sensation, and therefore neither here. But it is the vessel and chest of the sensitive virtues, containing subtle nerves, in which the senses and sensitive spirits consist. But it must be considered, so that every doubt may be removed, that the sensitive soul has a twofold instrument or subject: one is radical and fontal meaning: originating from the fountainhead/source, and this is the heart according to Aristotle and Avicenna in the book On the Soul. The other is that which is first changed by the species of sensible things, and in which the operations of the senses are more manifested and distinguished, and this is the brain. For when the head is injured, a manifest injury to the sensitive virtues occurs, and the injury of the head is more manifest to us than [that of] the heart, and it happens more often; and therefore, according to a more manifest consideration, we shall place the sensitive virtues in the head, and this is the opinion of the physicians, who do not estimate that the fontal origin of the virtues is from the heart. But Avicenna, in the 1st [book] of the Art of Medicine, says that although the opinion of the physicians is more manifest to the senses, the opinion of the Philosopher referring to Aristotle is truer, since all the nerves, and veins, and virtues of the soul arise from the heart first and principally, as Aristotle demonstrates in the 12th [book] of On Animals, and Avicenna shows in the 3rd [book] of On Animals.