APPREHENSION. — In philosophical, especially Scholastic, language, apprehension (from ad-prehendere, to take, to grasp) broadly designates every perceptive act by which the mind becomes aware of something; in a strict sense, it is the first operation of thought, generating the pure concept, prior to the synthesis of affirmation or negation realized in judgment. In the first sense, apprehension is almost synonymous with perception and is used by St. Thomas Aquinas also to designate sensory perception (In Boeth. De Trinit., VI, 2). In the more specific meaning, apprehension, contrasted with judgment, represents in man the initial form of spiritual knowledge that brings us into contact with the intelligible contents and values of things. For this reason, the Scholastics called it “apprehensio simplex, cognitio essentiarum, indivisibilium intelligentia” (cf. St. Thomas Aquinas, I Perihermeneias, 1). It is well known that in Thomistic philosophy apprehension, as an act of thought by which the quiddity of things is grasped more or less distinctly, is realized chiefly through an abstractive operation of the intellect (v. ABSTRACT; ABSTRACTION). It is worth noting, in relation to the theory of knowledge, the realistic meaning that emerges from the etymology of the term: ad prehendere, as a movement of thought toward the object to seize it in the intentional unity of the concept.
A final, more technical and less common meaning is that in which apprehension is contrasted with comprehension, as partial knowledge limited to adequate and total knowledge.