Knowledge of particular objects and its forms


The Philosophy of Thomas Aquinas, by Jonathan Dolhenty

II. B. Two irreducible types of knowledge: Knowledge of particular objects and its forms


It is of great importance to note that scholasticism distinguishes between two quite different kinds of knowledge: sense knowledge, and intellectual knowledge. In the case of the first — the perception by sight of an oak tree, for instance — everything that I grasp is particularized or individualized, and intimately bound up with conditions of space and time. What I see is

this oak tree,
with a trunk of this particular form,
with a bark of this degree of roughness,
with these particular branches and these leaves,
in this particular spot in the forest,
and which came from a particular acorn at a particular moment in time.
If I touch the tree with my hand,

the resistance which I encounter is this resistance,
just as the sound which I hear in striking the bark is this sound.
Our external senses (sight, hearing, smell, taste, touch) put us in contact either with something which is a proper and peculiar object of one sense and which each sense perceives to the exclusion of all the others (sensibile proprium), for instance, color in the case of sight; or else the common object (sensible commune) of more than one sense, for instance, shape in the case of sight and touch. But in every case the reality perceived by sense is always endowed with individuality.

The same is true of those sensations which are called internal, and which originate, in the scholastic system of classification,

from sense-memory (a),
from sense-consciousness (b),
from instinct (c),
or from imagination (d).
These are simply so many labels attached to psychological facts which have been duly observed and noted. A few examples will make this clear.

(a) Sense-memory. When I have ceased to look at the oak tree, there remains in me an after-image, which is said to be ‘preserved’ in memory, since I am able to ‘reproduce’ it. We thus possess in ourselves a storehouse of after-images received through the senses [4], which can be reproduced either spontaneously, or else at the command of the will. It is clear that these vestiges of past sensations, retained and reproduced in this way, are individualized just as the original sensation. If I picture to myself an oak tree, it will always be a picture of one individual oak tree. In the same way, when we realize that a sense perception, or a conscious act of our physiological life, has a certain duration, or takes place after another activity, this realization, which itself involves sense-memory, is once more individual and singular, and presents us with this particular time. The recognition of past time involves reference to particular psychological events, following each other.

(b) Sense-consciousness. Moreover, when I look at an oak tree, something in me tells me that I see. I am aware that I am seeing. My sense perception is followed by ‘sense-consciousness,’ and the content of this sense-consciousness is particularized. Again, the complex sense cognition of this oak as an object is the result of the coordination of many perceptions coming from different senses: the height of the tree, the roughness of its bark, the hollow sound which its trunk gives when struck. There is reason to attribute to the higher animals and to man a central sense, which combines the external sense perceptions, compares them, and discriminates between them. But, in this case also, the result of these operations is individualized, and if we compare for instance two complex sense perceptions of oak trees, each is itself and not the other.

(c) Instinct. We can apply the same to the way in which we recognize that a certain situation is dangerous for us or otherwise. We possess a discriminating power which estimates certain concrete connections between things. We naturally flee from fire, and a shipwrecked man clutches instinctively at a plank, much in the same way as a lamb looks upon a wolf as dangerous, and a bird considers a particular branch of a tree as a suitable resting-place for its nest. This act of sense knowledge always related to a particular, concrete situation.

(d) Imagination. Again, the constructive imagination, which takes the materials supplied by sense-memory and combines them into all sorts of fantastic images — when I imagine, for instance, oak trees as high as mountains, and monstrosities half lion half man — deals with what is particularized. What modern psychologists might call a composite image is to the Schoolmen simply a particular image, made up of characters derived from other particular images.


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.