Nature of the estimative sense.
This power is called “instinct.” By means of this power, the animals are capable of perceiving the beneficial and harmful character of concrete objects. The perception of such beneficial or harmful character is followed by a movement of the sense appetite to attain the beneficial object or to avoid the harmful one. The purpose of this cognitive power is the good of the animal.
The existence of the estimative power is evident from observation. Animals, for example, know what kind of food is good or harmful for them, and the lamb spontaneously avoids the wolf. Although experience helps this power, the apprehension of what is harmful and beneficial need not be based upon previous sensations of the harmful or beneficial character of a particular object. For this reason, we may say that the estimative power perceives “insensate intentions,” i.e., objects of knowledge not yet sensed by any other external or internal sense.
The operation of the estimative power is similar to what is called “knowledge through affinity,” which inclines the human being through immediate intuition to avoid what is evil and to tend towards the good. For example, we instantaneously withdraw our hand from a hot oven. The estimative power depends upon the disposition of the body in its judgment. This is obvious, for example, in the case of the mating season of animals.
The estimative power in human beings is called the cogitative power:
Animals perceive these intentions only by some natural instinct, while man perceives thee by means of coalition of ideas. Therefore, the power which in other animals is called the natural estimative power, in man is called the cogitative power, which by some sort of collation discovers these intentions. Wherefore it is also called the particular reason for it compares individual intentions, just as the intellectual reason compares universal intentions.ST I, 78, 4, co.
Functions of the cogitative power.
The cogitative power has the following functions:
- To know the sensible per accidens in individuals, e.g., to know that the red color belongs to that man.
- To consider individual things as sharing a common nature: The cogitative faculty apprehends the individual thing as existing in a common nature. It is able to do this because it is united to intellect in one and the same subject. Hence it is aware of a man as this man, and of a tree as this tree; whereas instinct is not aware of an individual thing as in a common nature, but only insofar as this individual thing is the term or principle of some action or passion. Thus a sheep knows this particular lamb, not as this lamb, but simply as something to be suckled; and it knows this grass just insofar as this grass is its food. Hence, other individual things which have no relation to its own actions or passions it does not apprehend at all by natural instinct. For the purpose of natural instinct in animals is to direct them in their actions and passions, so as to seek and avoid things according to the requirements of their nature.(In de anima, n.398.)
- To prepare the phantasm for the intellect.
- To deduce individual conclusions from universal and particular premises:
- To steal is evil.
- This is to steal.
- Therefore, this is evil.
- The cogitative power is thus a sort of bridge between the intellect and the senses.