Subsection 10. Understanding

Understanding is a power of the soul through which we perceive, know, remember and judge both particular and universal things. It possesses certain inborn notions or rudiments of the arts and a reflective activity through which it judges and examines its own operations. Besides identifying its chief function—to apprehend and judge all that it does without the help of instruments or organs—this definition reveals three differences between a human being and a beast.

First, sense comprehends only particulars, while understanding comprehends universals. Second, sense has no innate notions. Third, beasts cannot reflect upon themselves. Bees and many other creatures do indeed make neat and intricate works, but once they have finished, they cannot judge them. The object of understanding is God, being, all nature and whatever can be understood; it apprehends these successively.

The object that first stirs understanding is something perceptible to the senses. Afterwards, by reasoning, the mind discovers corporeal substance and proceeds from there to spiritual substance. Its activities, some say, are apprehension, combination, separation, discursive thought, reasoning and memory; some include these under discovery and judgement. Understanding is commonly divided into active and passive, speculative and practical, habitual and actual, simple and compound.

The active understanding is what we call human wit: acuteness, subtlety or sharpness of discovery, exercised when someone discovers something independently, without a teacher, or learns something new. It abstracts intelligible forms from the imagination and transfers them to the passive understanding, because nothing is in the understanding that was not first in the senses.

The active understanding judges whether what imagination has taken from the senses is true or false. Having judged it, it entrusts it to the passive understanding for safekeeping. The active understanding is a teacher; the passive is a pupil, whose function is to preserve and further judge what is entrusted to it. At first it is like a blank tablet wiped clean, capable of receiving every form and notion.

These notions are of two kinds: acts and habits. Acts are those through which we form notions of things and perceive them; habits are lasting illuminations and notions that we can use when we choose. Some reckon eight kinds: sense, experience, intelligence, faith, suspicion, error, opinion and certain knowledge. To these are added art, prudence and wisdom, together with synderesis, the dictate of reason and conscience. Thus there are fourteen kinds of understanding in all. Some, such as the last three, are innate; the others are acquired through instruction, learning and practice.

Plato holds that all are innate. Aristotle reckons only five intellectual habits, two of them practical: prudence, whose end is action, and art, whose end is making; wisdom comprehends the use and experience of all notions and habits whatsoever. Properly considered, this division of Aristotle agrees with the preceding one: three are innate and five acquired, while the rest are improperly named or imperfect, and excluded on closer examination. I ought to discuss all these more fully, but my subject will not allow it. I shall touch only on three, which are more necessary to the discussion that follows.

Synderesis, or the purer part of conscience, is an innate habit: the preservation of knowledge of the law of God and nature, enabling us to distinguish good from evil. As our theologians hold, it belongs to the understanding rather than the will. It supplies the major proposition in a practical syllogism. The dictate of reason prompts us to do good or evil and supplies the minor proposition. Conscience judges good or evil, justifying or condemning our actions, and supplies the conclusion.

Take the familiar example of the Roman Regulus, captured by the Carthaginians and allowed to go to Rome on condition that he return or pay a stipulated ransom. Synderesis lays down the principle: his word, oath or promise must be scrupulously kept, even when given to an enemy, as the law of nature requires. Do not do to another what you would not want done to yourself.

The dictate of reason applies this to him and says something like: “Regulus, you would not want another person to falsify his oath or break a promise made to you.” Conscience concludes: “Therefore, Regulus, you do right to fulfil your promise, and you ought to keep your oath.” More on this in Religious Melancholy.