Metaphysics

Concerning material substance, we must not fail to notice that even if all things come from the same primary thing, or from the same things as primary, and the same matter is the principle for things that are generated, nevertheless there is a certain appropriate matter for each thing, for example, of phlegm, the sweet or the fatty, and of bile, the bitter or some other things; though perhaps these latter come from the same thing. And multiple matters of the same thing arise when one of them is the matter of the other, as phlegm comes from the fatty and the sweet if the fatty comes from the sweet, and it comes from bile by the bile being analyzed into the primary matter. For ‘this from that’ is said in two ways: either because it is on the way, or because it has been analyzed into its principle. And it is possible that when the matter is one, different things are generated owing to the moving cause, as both a chest and a bed are made from wood. But of some things, the matter is of necessity different when the products are different; for example, a saw cannot be made of wood, nor does this depend on the moving cause, for it will not make a saw out of wool or wood. But if indeed it is possible to make the same thing from different matter, it is clear that the art, that is, the principle as mover, is the same; for if both the matter and the mover were different, the product would be so too. Since, then, causes are spoken of in many ways, when one inquires into the cause, one must state all the possible causes. For example, what is the cause of man as matter? Is it the menstrual fluid? And what is it as mover? Is it the semen? And what is it as form? The essence. And what is it as that for the sake of which? The end. But perhaps these two are the same. And one must state the nearest causes. What is the matter? One must state not fire or earth, but the proper matter. Therefore, concerning natural and generated substances, if one is to proceed correctly, one must proceed in this way, if indeed these and so many are the causes, and one must know the causes. But in the case of substances which are natural but eternal, the account is different; for perhaps some of them do not have matter, or not this sort of matter, but only such as is movable in space. Nor indeed is there matter for those things which, though by nature, are not substances, but their substrate is the substance. For example, what is the cause of an eclipse, what is its matter? There is none, but the moon is the thing affected. And what is the cause as having moved and destroyed the light? The earth. The final cause, perhaps, does not exist. The formal cause is the formula, but it is unclear if the formula does not include the cause. For example, what is an eclipse? Privation of light. But if there is added ‘by the earth coming in the middle,’ this is the formula containing the cause. Concerning sleep, it is unclear what the primary thing affected is. Is it the animal? Yes, but in virtue of what part, and what is primary? Is it the heart or something else? Next, by what is it caused? Next, what is the affection—that of that part, and not of the whole? That it is a certain kind of immobility? Yes, but this is due to the primary thing undergoing what?

​Since some things exist and do not exist without generation and perishing, like points, if indeed they exist, and in general forms (for it is not whiteness that is generated, but the wood becomes white, if indeed everything that is generated is generated from something and into something), not all contraries would be generated from one another, but a white man is generated from a black man, and whiteness from blackness, in different ways. Nor is there matter for everything, but only for those things of which there is generation and change into one another; but for those things which exist or do not exist without undergoing change, there is no matter. But there is a difficulty as to how the matter of each thing is related to contraries. For example, if the body is potentially healthy, and disease is contrary to health, is it potentially both? And is water potentially wine and vinegar? Or is it the matter of the one according to the state and the form, but of the other according to the privation and the contrary-to-nature perishing? There is also a certain difficulty as to why wine is not the matter of vinegar, nor potentially vinegar (even though vinegar comes from it), and whether the living thing is potentially dead. Or is it not so, but the perishings are accidental, and the matter of the living animal is itself, in virtue of perishing, the potentiality and matter of a dead body, and water that of vinegar? For they come from these as night comes from day. And indeed, whatever things change into one another in this way must return to their matter; for example, if a living animal is to come from a dead one, it must first return to its matter, and only then become a living animal; and vinegar must return to water, and only then become wine.