Introduction to Astronomy

For example: I sustain, you sustain original: "Sustento sustinēs" is more ancient, just as the earth is more ancient than earthly bodies. Thus, in composite things, the matter is more ancient than the form. The genera and species of animals, plants, and metals exist in nature by potential; but they exist in actuality only when composition finally follows. Nor can there be composition unless there is a composer who, in some way, brings it about; for a composite thing cannot be its own composer or its own matter. Since these things are so, it follows that there is a Creator original: "genitoꝛē": a discerner of all nations and all composite things, who distinguishes between the genera and species of all. From this, it is clear that there is a Craftsman of all created things and of their diversity; he then entrusted the guidance of nature to the motions of the stars. Indeed, the power of this kind of composition and its differences is gathered from celestial motion; for it is only in the composition of individuals and the differences of species that the harmony of soul and body specifically prevails.

Since, therefore, every composite thing consists of form and matter, the form—being prior—seeks out and adapts the matter to itself. Hence, in philosophy philosophy: here referring to natural science and metaphysics, form is compared to the craftsman, while matter is compared to the tools. For just as different craftsmen work with their own tools and need nothing belonging to others—and the work is ascribed not to the tools but to the craftsman—so it is with different forms. This form is not that of a beast or a bird; for what is naturally suited to a man is foreign to a beast. Thus, one thing belongs to a beast, another to a bird. The human form takes from nature heat and moisture, and other things that are more subtle and fit for receiving a rational soul original: "aie rōnali" and for the movements of standing upright, sitting, and the like. But the form of a beast takes heat and dryness, suited for claws, teeth, bristles, and roughness; or the form of a beast takes cold and dryness, suitable for hooves and legs. Thus, every form draws to itself what is congruent from the passive matter. Therefore, every composite thing is principally ascribed not to the authority of the matter, but to the form.

Therefore, once all these principles that produce composite things are known, one may easily understand what comes from elsewhere, which must be attributed to the power of the stars original: "stellarū vtuti".

First, we distinguish the four properties of matter by three differences:
1. The variety of qualities, such as heat and cold.
2. The resolution of one into another: as earth into water, water into air, air into fire, and vice versa.
3. The reception of increase and decrease. For one part of air is moister than another; one part of earth is drier than another.

Form also has three other properties, different from these:
1. No variety exists within a form; for in that which is "rational and mortal," one is not more varied than another in being rational or mortal.
2. One form is not resolved into another; for a man never becomes a donkey.
3. It is capable of neither increase nor decrease; for one man is not more or less rational or mortal than another man.

By these principles, we know that everything in bodies comes from these sources where we find opposites, resolution, and growth or decay. For example, a man who is now hot, now cold, now passing from hot to cold, or now more or less hot or cold, is so because of matter. But that which is the opposite of these in its own kind is from form. That which is neither from matter nor from form—yet because nothing exists whose origin is not preceded by a legitimate cause and reason, and there is nothing else remaining in the lower part of the world to hold the place of a cause—must necessarily follow from celestial power. This includes the division and distance of genus from genus, species from species, and individual from individual; the harmony of souls and bodies; and innumerable other accidents, such as sex, the distinction of shape, the beauty or ugliness of appearance, inequality of stature, and various colors...