Aquinas: Abstract and General Knowledge

The Philosophical System of Thomas Aquinas, by Maurice de Wulf, Edited & adapted for the Web by Dr. Jonathan Dolhenty

II. C. Abstract and General Knowledge. 

Introspection shows us that we possess another kind of knowledge with characteristics quite different from those we have found in sense knowledge. Intellectual knowledge, instead of being concrete and particularized, is abstract and general. Let us consider this twofold character.

The act of vision of an oak tree, localized in a particular spot, is spontaneously accompanied by notions such as ‘height,’ ‘cylindrical form,’ ‘local motion,’ ‘color,’ ‘vital activity,’ ‘cell,’ ‘matter,’ ‘being.’ These notions are indeed derived from this oak tree, but the aspects of reality which we grasp by them are no longer bound up with this particular individual,: they reveal to me the whatness or essence (essentia, quidditas) [8], or in what height, local motion, life activity, combustion, etc., consist. We confine our attention to certain elements of the thing under consideration, shutting out all the other elements, and stripping them of all particularizing determinations. Abstraction consists precisely in this function and in nothing else. In what height consists is considered apart from everything else, and this selected aspect of reality is no longer related to this oak tree. So that the term abstraction has its etymological meaning (trahere ab, to select from, to draw from; abstraction is sometimes called praecisio mentalis). I possess a treasure-house of abstract notions which relate to all kinds and classes of reality.

It is precisely because this representative content, or object of thought (id quod menti objicitur), is no longer bound up entirely with the sight of any particular oak tree, or of a particular human being, etc., that it is seen upon reflection to be applicable to an indefinite number of beings which move, which are cylindrical in form, which manifest vital activities, which are material in nature, etc. This applicability is indefinite — it is ‘universal’ or general, and extends to possible realities as well as existent ones. Universality, therefore, follows upon abstraction, as Thomas remarks.

An abstract notion of mankind seizes what mankind is, as distinct from the whatness of an elephant or a particle of radium. A universal or general notion of mankind implies that such a reality is represented as being able to belong to an endless multitude of men. An abstract notion is thus not necessarily universal, but it may become so. If we bear this in mind, we shall be able to understand better the scholastic solution of the problem of Universals.

We said above that there is no such thing as a general image. Here we say that there is such a thing as a general idea — in fact, that all ideas are general. There is no contraction here. But those who are unaccustomed to introspection are often unconscious of the vital distinction between image and idea which underlies our two statements. The average man labels his mental content as ‘images’ and ‘ideas’ indiscriminately. Yet reflection will show that they are quite different, and that the one is general while the other is not. This will be made clear from the example of a geometrical theorem — for instance, that the angles of a triangle are together equal to two right angles. We go on at once to picture a triangle, and we say, “Let ABC be a triangle,” and so on. But this image of a triangle is a particular one, whereas our reasoning applies to any and all triangles, existent or only possible. It is thus obvious that the idea or concept triangle is abstract and general, whereas the image is not. The image is here simply a help to our mental consideration and reflection.

The knowledge of reality by means of abstract and universal notions is quite distinct from the particular, individualized knowledge of the external and internal senses. The Schoolmen emphasize this difference by attributing abstract to the intelligence (intellectus) or reason (ratio). The prominent place occupied in scholasticism by this doctrine of abstract and general knowledge, which we may describe as ‘Psychological Spiritualism’ or better still as Intellectualism, gives the system a definite place in the brilliant group to which belong Plato, Aristotle, Augustine, Plotinus, and in later times, Descartes, Leibnitz, Kant.

Abstraction is the privilege and the distinctive act of man. It is likewise the central activity of our conscious life. The intellectualism, which results from this theory, has an influence over all the branches of philosophy, and we shall see that the rights of human reason are proclaimed and defended at every stage of thought.

The late Dr. Jonathan Dolhenty was the Founder and President of The Center for Applied Philosophy and the Radical Academy, and is Honorary Philosophy Editor at The Moral Liberal. The Moral Liberal has adopted these projects beginning with a republishing and preserving of all of Dr. Dolhenty’s work.