ESTIMATIVA. — It is the interior faculty by which an animal learns things useful or harmful to its life, and corresponds to what modern psychology calls instinct. Since the soul is devoid of reason, it cannot form these value judgments by itself; therefore, they must be innate in its psyche and immediately activated upon first contact with reality. This faculty judges things not by their external qualities but by their intrinsic value: “… just as a sheep, seeing a wolf coming, flees, not because of the wolf’s color or shape, but as if recognizing a natural enemy. Likewise, a bird gathers straw, not because it pleases the senses, but because it is useful for nest-building” (Sum. Theol., 1a, q. 78, a. 4 c). Thus, it represents the highest degree of knowledge in animals, guiding them in their conduct of life. In humans, the corresponding faculty is the cogitativa. (cf.)
