that which belongs to the ear. For here to know that a thing is, is the province of those who exercise the sense, but to know why it is, belongs to mathematicians, since these possess the demonstrations of causes, and often are ignorant of the that, as they who contemplating universals, frequently are ignorant of singulars from want of observation. But these are such as being essentially something else use forms, for mathematics are conversant with forms, since they do not regard one certain subject, for though the geometrical are of a certain subject, yet not so far as they are geometrical are they in a subject. As optics also to geometry, so is some other science related to optics, as for example, the science about the rainbow, for to know that it is, appertains to the natural philosopher, but why it is, to the optician either simply or mathematically. Many sciences also which are not arranged under each other subsist thus, for example, medicine with regard to geometry, for to know that circular wounds heal more slowly is the province of the physician, but why (they do so) of the geometrician.
Chapter 14
Of the figures, the first is especially adapted to science, for both the mathematical sciences carry
