Autor: Thomas Aquinas

Buch: Aquinas on Being and Essence

Titel: Aquinas on Being and Essence

Stichwort: Metaphysik, Logik; erste, zweite Intention (prima - secunda intellecta); Art, Gattung, spezifische Differenz; logische Intentionen (Relationen, die im Verstand existieren)

Kurzinhalt: Most simply described ... logical intentions are relations discoverable by the mind among its many different grasps of real things... (secunda intellecta); for the intellect comes to know them by reflecting on itself, by knowing that it knows and the ...

Textausschnitt: Second Intentions, Logic, and Metaphysics

16a The genus, the species, and the difference represent diverse intellectual grasps or expressions of things. Each expresses the thing as to what the thing is—i.e., as to its essence—but each in a different way: the genus expresses the common part of what the thing is; the difference, the proper or distinctive part; the species, the whole thing, i.e., the whole of what the thing is. The two remaining predicables—namely, property and accident—are not expressive of what a thing is. Since St. Thomas' effort in this treatise is a most economical one and since it begins by focusing on the analytical beginning point of human intellectual knowledge, it is clear why he chooses to consider only those logical intentions which relate to the intellect's first operation, simple apprehension. And since the analytical beginning point of human intellectual knowledge is a grasp of being and essence, it is clear why he chooses to consider only those logical intentions which relate to our grasp of what things are; it is clear, therefore, why he does not consider the intentions property and accident. (Fs) (notabene)

16b It is precisely because of the fact that we, as human knowers, have many different grasps of things, that logical intentions enter the domain of human knowledge. In an intellect which grasps everything by but one concept, there would be no place for logical intentions. Most simply described (i.e., at the level of the intellect's first operation, simple apprehension), logical intentions are relations discoverable by the mind among its many different grasps of real things. (Fs) (notabene)

16c It is the view of St. Thomas that the things which logic investigates as its subject are intentions which are only secondly known; they have come to be called second intentions. He explains what he understands by such intentions:
What is first known (prima intellecta) are things outside the soul, the things which first draw the intellect to knowledge. But the intentions which follow on our mode of knowing are said to be secondly known (secunda intellecta); for the intellect comes to know them by reflecting on itself, by knowing that it knows and the mode of its knowing.1

17a Then, in what immediately follows, he offers genus, species (also second substances) as examples of such intentions. (Fs)

17b To make clear what logical, or second, intentions are, one must begin by noticing that they are opposed to first intentions. First intentions are meanings or concepts derived from, or at least verified in, extramental, or real, things. For example, the meaning we derive from those things which are men, and to which we attach the word "man," i.e., the meaning "rational animal"; the meaning we derive from those things which are animals, and to which we attach the word "animal," i.e., the meaning "sensitive organism." Second intentions are meanings derived from, or verified in, first intentional meanings; second intentions are characteristics which belong to meanings derived from real things (i.e., to first intentions), not only because of these meanings but also because these meanings are in the grasp of a human intellect. If one compares the meaning which he attaches to the word "animal" with the meaning he attaches to the word "man" (this presupposes a possession of each meaning), it is easy to see that the meaning of the word "animal" is part of the meaning of the word "man." For a meaning to be part of another meaning is a second intention, a characteristic (here a relation) discoverable by the intellect between two possessed meanings, a relation which belongs to first intentional meanings both because of the meanings themselves and because these meanings are known by a human intellect. If we consider the meaning we attach to the word "dog," it is easy to see that the meaning of the word "animal" is part of its meaning as well as part of the meaning of the word "man." It is thus the (or a) common part of the meaning of both. This is roughly what it is for a meaning to be a genus. If some meaning A is part of some meaning D and also part of some meaning M, then A is, roughly speaking, the (or a) genus of D and M. (Fs)

18a It is to be noticed that the first intentional meanings being compared exist in a human intellect. Second intentional relations are, therefore, relations between terms which exist in the intellect. The relations themselves, therefore, exist in the intellect. Second intentional relations are not real relations; they are not relations which belong to things outside the mind precisely as outside the mind; for example, Jack's being one inch taller than Paul; Paul's being Jack's father. Nor are second intentional relations characteristics which belong to things because of, and only because of, what these things are, i.e., only because of the first intentional meanings derived from these things; for example, the incorruptibility of the human soul; such characteristics are first intentions. Second intentional relations are characteristics which belong to things as known, not to things as things. (Fs)

18b The following points will help to clarify the preceding. (1) If being a genus belonged to animal as animal (i.e., to animal because of, and only because of, what the word "animal" means), then only the meaning of the word "animal" could be a genus. But this is clearly not the case. One can find any number of meanings which are related to other meanings as their genus. For example, the meaning of the word "body" is a genus in relation to the meaning of the word "organism" (i.e., living body) and to that of the expression "nonliving body"; the meaning of the word "organism" is a genus in relation to the meanings of the words "plant" and "animal."
18c (2) One must notice the difference between (a) what it is to be a genus and (b) that which is a genus. The former is a second intention; the latter, a first intention. To be a genus is to have a relation of a certain sort (genericity) to other meanings. Animal has such a relation to man and dog. And it is because of this relation that animal is called a genus; and this in a way similar to the way in which Paul is called Jack's father because of the relation (real) of fatherhood. One must notice the same distinction between what it is to be a species (specificity) and that which is a species; also between what it is to be a specific difference and that which is a specific difference. (Fs) (notabene)

19a (3) Out of the preceding, one has a clear way of pointing out what logic is about. Logic considers questions like (a) what does it mean to be a genus, a species, a specific difference, and (b) what belongs to—i.e., what are the properties or more generally the per se accidents of—a genus as genus, a species as species, a specific difference as specific difference. Some science other than logic considers questions like (a) what is the genus animal—i.e., what does it mean to be an animal—and (b) what belongs to animal as animal (philosophy of nature); and questions like (a) what is the genus triangle—i.e., what does it mean to be a triangle—and (b) what belongs to triangle as triangle (mathematics); and questions like (a) what is the genus substance—i.e., what does it mean to be a substance—and (b) what belongs to substance as substance (metaphysics). An example of a simple proof in the logic of the first operation of the intellect, simple apprehension, will be of some help here:

To show: A category cannot have a specific difference.
Proof: A specific difference is what differentiates
species in a same genus.
Thus, whatever has a specific difference must
have a genus. But a category is a genus which
has no genus of itself. Therefore, a category
cannot have a specific difference.

19b (4) It will be helpful to mention other examples of second intentions. Apropos of the first operation of the intellect: to be a universal, a predicable, a category, a definition. For the second operation of the intellect: to be a proposition, a subject, a predicate, a copula, a contradictory, a contrary; to be true, false, implied. For the third operation of the intellect: to be a deduction, an induction, a syllogism, a necessary syllogism, a middle term, a major term, a minor term, a fallacy, the subject of a science. (Fs)

20a From the preceding, one can understand that whenever a human knower confronts a knowable thing, the knowledge which is a result of this confrontation bears the stamp of the knower. The knowledge which is a result of this confrontation has characteristics deriving from the extramental things which are said to be known, but this knowledge also has characteristics deriving from our condition as beings who know extramental things in terms of a great number of different grasps or concepts or meanings. It is important, therefore, to be aware of what enters our knowledge from our condition as human knowers. This is important in order to avoid attributing to things what does not belong to them. And this is why St. Thomas considers the question of the relation of being and essence to logical intentions. (Fs) (notabene)

20b From the preceding, one can also understand what St. Thomas takes to be the difference between logic and metaphysics, indeed between logic and the whole of philosophy. Whereas the whole of philosophy is about real things, from different points of view, logic is about second intentions, which are not real things. Whereas logic and metaphysics can be said to be about all things (excluding God) as about a subject, metaphysics is about them as things, i.e., about those common features of things which are essential to and intrinsic to them, and which they have independently of our way of knowing them. But logic is about them as known, i.e., about those common features of things which are only incidental to them, which we come to attribute to them not as their own but precisely because of the way in which we know them, which we understand therefore to belong to what enters our knowledge from our condition as human knowers. (Fs)