PERSPECTIVE PART ONE: DISTINCTION I.

through sight. If, however, we allege taste, touch, and smell, then we are assuming a beastly wisdom. For brute animals concern themselves with things to be tasted and touched, and they exercise smell for the sake of taste and touch. But the things about which these senses offer certification are base, few, and common to brute animals, and therefore they do not rise to the dignity of human wisdom. Furthermore, sciences are established because of necessity, utility, and difficulty, because art concerns the difficult and the good, as Aristotle says in the second book of the Ethicorum Ethics. For if that which is sought is easy, it is not necessary to establish a science. Similarly, even if it is difficult, if it is not useful, a science is not made of it, because the labor would be foolish and empty. Also, unless it were very useful and held many clear truths, a separate science should not be established; rather, it suffices that it be determined in some partial book or chapter along with others in a common science. But among philosophers, a separate science is established for sight alone, such as perspective, and not for any other sense. Therefore, there must be a special utility of wisdom through sight that is not found in other senses. And what I have now touched upon in a universal way, I wish to exhibit in particular by turning through the roots of this most beautiful science. Indeed, some science may be more useful, but none has such sweetness and beauty of utility. And therefore it is the flower of all philosophy, and through it, and not without it, other sciences can be known. It should be known, however, that Aristotle first composed this science, of which he speaks in the second book of the Physicorum Physics, where he says that the subject is subalternated, and in the book De Sensu et Sensato On Sense and the Sensible, and he refutes Democritus because he did not name the fractions and reflections of vision from optics and from the concave visual nerves, which is translated into Latin. After him, Alhazen explains it more abundantly, which is what we have. Alkindi also composed some things more abundantly, as did the authors of the books on vision and mirrors.