Man's Knowledge of Bodily Reality

Man’s spiritual soul is the life-principle and the substantial form of the human living being. It is the root-principle of all vital activities in man. Its own properfaculties are the intellect and the will. But the soul is the substantial form of a body, and even its spiritual faculty of intellect must attain knowledge through the body and its senses. Therefore, in this present life, the proper object of the human intellect is the essence of material things which the senses lay hold of. The process by which the intellect gets its knowledge may be thus illustrated: A boy looks at five pictures ofa triangle, drawn in different colors and in various sizes. The sense of sight takes in the pictures; the inner sense of imagination or phantasy expresses within itself these sight-images,and they are now called phantasms. The active intellect (the intellectus agens) focuses on the phantasms and,disregarding differences of size and color and location of the pictures themselves, reveals what it is that they represent; this action of the active intellect is called abstraction. By abstraction, then, the active intellect, throwing its light onphantasms, de-materializes them, de-individualizes them, and renders them intelligible. It does not matter, therefore, that there are five or fifty pictures of triangle, or that they are drawn here or drawn there, that they are in this color or that; by its operation of abstraction, the active intellect disregards all these individualizing things and thus shows up the essence of triangle itself, triangle as such. This abstracted essence is called the intelligible species (that is, the understandable essence) of triangle. Thus sense-findings are prepared for the grasp of the spiritual power of the intellectproper (the intellectus possibilis). The active intellectimpresses the abstracted essence or species upon the intellectproper, and the intellect proper reacts to the impression by expressing the essence within itself as a concept or idea. The intellect now knows in idea what triangle is; it knows in universal, for it can now define triangle as such, and not merely this or that individual triangle. Thus does man rise from the individual findings of the senses to intellectual concepts and ideas which represent things in universal, or by definition of essence.

The intellect of man does not know things by its own essence, but must acquire its natural knowledge by its operation as just explained. Only God knows things by his own essence.

Nor has the human soul any knowledge born in it, orimparted to it with its nature as is the case with angels. Allman’s natural intellectual knowledge begins with the action ofthe senses. From sense-findings, intellectual knowledge is derived by abstraction. And the intellect may rise from concepts or ideas, by a further abstraction, to higher concepts or ideas. But no ideas are naturally inborn in man; there are no innate ideas. All man’s natural knowledge is acquired.

And, as we have seen, all ideas are, in last analysis,acquired by abstraction from phantasms, that is, imagination-images of sense-findings. Even ideas acquired from other ideas have to be traced back to the action of senses to start with. No ideas are impressed on man’s mind from outside by “forms” thatsubsist, as Plato taught. No other process than that described above accounts for man’s natural intellectual knowledge.

Man’s intellect may be described as a kind of light given man by the Creator, a sort of participation of the divine understanding. Therefore it may be said that the human intellect has, in its imperfect creatural way, ideas that are in Godeternally as archetypes and exemplars.

Sense-knowledge supplies what may be called the material from which the active intellect draws out or abstractsunderstandable forms. Hence, by metaphor, sense-knowledge may be called the material cause of intellectual knowledge.

Just as the intellect acquires ideas from phantasms, soit turns to phantasms when it uses knowledge already acquired. We know that this is so, for sometimes a bodily injury or disease may prevent a man from understanding what he previously understood. And when we wish to think a thing out, we use examples to help ourselves understand, and such examples are phantasms; we also explain things to others by use of examples. While the intellect is a spiritual power and understands in universal, it is never, in this earthly life, wholly divorced from material things and individual sense-grasp. The intellect of bodily man acquiresknowledge through phantasms, and uses acquired knowledge by recurring to phantasms.

Therefore when the senses are impaired, the judgment ofthe mind or intellect is hampered. This does not mean that the intellect depends essentially on the senses, but that, in this earthly life, there is an extrinsic dependence of intellect on sense.