International Catholic University
Sciences are distinguished from one another by their subject matters. Since science involved demonstration, and a demonstration is a kind of argument, we must first know what an argument is. A proof.
Aristotle was the first to analyze discursive reasoning, what he called syllogism . . . A syllogism is showing that something is so because other things are so . . . Certain statements being true, another statement follows from their being true
If p then q
But the antecedent here is a set of statements or propositions the conjunction of which yields a third
The aim of discourse is to establish the truth of S is P
If this is to follow from the truth of other propositions, what must those propositions look like?
If S is M, and M is P, then S is P.
A demonstration is a syllogism which concludes a necessary truth and this requires that its premises too be necessary.
The subject of a science is the subject of the conclusion of a demonstrative syllogism.
But isn't a science a body of knowledge, a set of demonstrations . . . Yes, and they are related in such a way that a generic subject includes specific ones . . .
Thus there can be a network of connected demonstrations and these make up a single science
"It should be said that it is the definition of science that from some known things others things are necessarily concluded . . . " -- Thomas Aquinas
In the course of doing natural philosophy, Aristotle has come to see that to be and to be material are not identical. He also notes the difference between natural science and mathematics. When Aristotle sets about the science made possible by this, he is careful to relate what he is seeking to what he already knows.
"There is a science which investigates being as being and the attributes which belong to this in virtue of its own nature. Now this is not the same as any of the so-called special sciences; for none of these others treats universally of being as being. They cut off a part of being and investigate the attribute of this part; this is what the mathematical sciences for instance do. Now since we are seeking the first principles and the highest causes, clearly there must be some thing to which they belong in virtue of its own nature." IV.1
Aristotle is comparing the science he is seeking with natural science and mathematics.
Natural science: being as changeable, mobile being
Mathematics: being as quantified
Metaphysics: being as being
Just as natural science seeks to prove what belongs per se and necessarily to mobile being -- its properties -- and mathematics what belongs per se and necessarily to discrete and continuous quantity, so metaphysics seeks to prove the properties of being as being.
"It should be known, therefore, that there are some things whose existence depends upon matter nor can they be found without matter. There are other things which, although they cannot exist apart from sensible matter, sensible matter is not included in their definitions . . . There are some things which depend upon matter neither in order to exist nor to be defined . . . " -- Thomas Aquinas
One has to be struck by the matter-of-fact way in which Aristotle announces that there is such a science. But the very comparisons he makes to the unquestioned sciences of nature and mathematics makes it difficult to know how such a science is possible.
While the claim that there are things true of all existing things seems unproblematical at first, it is difficult to know how to formulate the subject of a demonstration of which such properties could be proved. Just being? But what precisely is that? When we prove the properties of a square or triangle we have a definition of the subject matter that serves as the middle term thanks to which we can attribute the property of the subject.
But what is the definition of being?
"There are many ways in which a thing may be said to 'be', but all that 'is' is related to one central point, one definite kind of thing, and is not said to be by mere ambiguity. Everything which is healthy is related to health, one thing in the sense that it preserves health, another in the sense that it produces it, another in the sense that it is a symptom of health, another because it is capable of it."
Aristotle gives other examples, but this is his favorite
Some terms are univocally common, others are used equivocally . . . but here we have a controlled equivocity . . . a plurality of meanings that all refer to the same denominating form, health
Capable of, subject of ______
Preserves ____
Symptom of ____
One of these is controlling
"There is a science which investigates being as being and the attributes which belong to this in virtue of its own nature." -- Aristotle
"So too there are many senses in which a thing is said to be, but all refer to one starting point; some things are said to be because they are substances, others because they are affections of substance, others because they are a process toward substance, or destructions or privations or qualities of substance, or productive or generative of substance, or negations of one of these things or of substance itself. It is for this reason that we say even of non-being that it is non-being."
"For not only in the case of things which have one common notion does the investigation belong to one science, but also in the case of things which are related to one common nature; for even these in a sense have one common notion."
"It is clear then that it is the work of one science also to study the things that are, qua being. But everywhere science deals chiefly with that which is primary, and on which the other things depend, and in virtue of which they get their names. If, then, this is substance, it will be of substances that the philosopher must grasp the principles and causes."
"Hence to investigate all the species of being way being is the work of a scies which is generically (tw genei) one, and it investigate the several species is the work of the specific parts of the science."
These passages from chapter two of Book Four of the Metaphysics are crucial.
Just an many things are said to be healthy because, if they are not the subject of health, they relate to that which is healthy in that sense; so too things are said to be, to be beings, in many different ways, but this is so because either they are substances or they relate in some way to that which is substance.
Substance thus emerges as that which provides sufficient unity for there to be a science of being as being.
This solution, as we shall see, is productive of a problem of profound importance. Has Aristotle reversed his views on the trajectory proper to human knowledge, from the universal to the particular. Has he now put a premium on glittering generality, being as being?