The Soul's Parts, Activities, and Virtues:

Aristotle begins his discussion of the Intellectual Virtues by making a distinction between different parts of the soul. Earlier in the Nicomachean Ethics (and in several other works) he develops this distinction in a bit more detail. Here, we'll focus just on the distinction as he uses it in book 6. The most fundamental division he makes is between two main parts of the soul:

• One part of the soul, the higher part, is Rational -- that is, fully rational, the part of us that reasons things out, that thinks, that contemplates, that possesses and develops knowledge.
• The other, lower, part of the soul is Non-Rational -- this part of the soul handles all of the basic life-functions, many of which we are not conscious of (e.g. digestion), and it is also the part with which we feel emotions, which desires. A sub-part of this part, while not itself rational, can participate in or listen to reason.

Moral Virtues are matters of the lower part of the soul - they are habits (hexeis) of acting, desiring, feeling that tend to produce the right action or emotional response in particular circumstances.

Intellectual Virtues have to do with the higher part of the soul - they are also habits, which need to be developed over time, but have to do with how the higher part of the soul is used.

Aristotle also divides the rational part of the soul into two parts. The distinction that he makes has to do with the kinds of objects or matters that the parts engage with in the course of their intellectual activity.

• Some matters are unchanging -- or at least their causes and principles are unchanging. Once one has fully learned or understood them, the knowledge that one has ought to remain constant. The highest part of the soul contemplates, investigates, learns, and comes to have knowledge of these. Mathematics, astronomy, physics, biology are examples of these kind of matters
• Other matters are by their very nature changing or at least changeable -- while we can develop general ideas and guidelines in respect of these, they are matters that could, and often do, turn out differently. We can always learn more, and even then, we might end up getting something wrong, when it gets down to the level of particulars. Some examples of these kinds of matters are the those we are concerned with when it comes to political life, ethics, productive crafts, etc. These are contemplated by the lower sub-part of the soul's rational part.

Aristotle also tells us that these parts of the soul themselves differ in another important way -- they have a kind of affinity or connection with the kinds of things they study and occupy themselves with. The highest part of the soul will therefore bear a kind of resemblance or likeness to the kinds of things that it is focused on. Likewise the second-highest will also bear this kind of resemblance -- it will be the part that carries out calculation or deliberation, because it deals with the kinds of things that require some weighing of options, thinking matters through, deliberating -- that is, practical matters.

The various intellectual virtues of the soul will line up with these parts of the soul. Aristotle discusses five of these, and of these, two (scientific knowledge and wisdom) will clearly be situated in the highest, scientific part of the soul. Two others (art or skill, and practical wisdom) will be situated in the deliberative part of the soul. One other one (intuitive reason or mind) might seem to be located solely in the scientific part of the soul, but actually turns out to be involved in the deliberative part as well.

Goodness, Truth, Activity, and The Soul:

Each part of the soul has its distinctive form of goodness -- or you might say, its own mode of operating as it ought to be. In his discussion, Aristotle will connect these with the notion of truth. Truth is something that will vary in its nature depending on what kinds of matters we are focused upon.

In speculative or theoretical matters -- the matters that the theoretical intellect is concerned with, for which the virtues are scientific knowledge and wisdom -- truth means a conformity of the intellect, the understanding or thought of the person, to how things actually are -- in what it affirms or denies. The good state for the theoretical intellect -- the state in which it is functioning properly -- is truth, and the bad state for the theoretical intellect is falsity.

In practical matters -- matters concerned with action, with choice and deliberation, with right and wrong, good and bad -- matters about which the practical intellect is concerned, the virtue of which is practical wisdom, things are a bit more complex. There is also truth and falsity in the practical intellect, but "truth" means truth in accordance with "right desire" -- the person not only has to know things rightly, have the right understanding of moral or practical matters, but also desire and choose things in the right way -- a way in which reason and desire are in harmony in the person who is deliberating, choosing, and acting.

In matters of production -- matters concerned with arts, skills, or activities that generate some sort of product, Aristotle does not actually tell us what would determine truth or falsity. But, presumably there are two ways to think about this. On the one hand, productive activity is also to a certain extent practical activity, so it would be governed by the same criterion: true reason in conformity with right desire. On the other hand, each art or skill has its own internal standards, and its determinate goal -- so another way of thinking about truth and falsity would be whether the product meets those standards and goals or not.

The Five Intellectual Virtues:

Each of the intellectual virtues -- specific modes of excellence in the person's intellect who possesses them -- is a way in which the intellect has or lacks -- and investigates, learns, acquires, or mistakes, forgets -- truth of one sort or another. So, what are these five virtues -- or states -- and what makes them ways in which a person possesses (and uses) truth?

• Scientific Knowledge (in Greek, episteme). This could also be called "disciplinary knowledge". This involves the intellect understanding matters whose basic starting points or causes do not change over time, or from situation to situation. Mathematics and Physics are two good examples of this kind of knowledge. This sort of knowledge may possess important practical applications, but the knowledge itself -- and the way the intellect is used in learning, investigating, and thinking about these sorts of matters -- is theoretical.
• Art (in Greek, techne). This can also be called "skill", "know-how", or "productive knowledge". It is the sort of knowledge or understanding that allows its possessor to be able to produce some desired thing or effect. It is practically concerned -- one wants the product or effect because it is regarded as some kind of desired good.
• Practical Wisdom (in Greek, phronesis). This can also be called Prudence. It is the kind of knowledge that is involved in understanding, judging, and deliberating well in practical matters -- in difficult choices, policies, moral matters, concerns of one's own or other people's goods. The person who has practical wisdom reasons well in practical matters.
• Intuitive Reason (in Greek, nous): It can also be called "intuition" or "intelligence". This is the kind of knowledge of the basic, fundamental starting points that are required for and used by Scientific Knowledge in its own activity. Practical reasoning also requires Intuitive Reason, but in a somewhat different manner.
• Wisdom (in Greek, sophia): In its strictest sense, Aristotle thinks that Wisdom is really a kind of integration of Intuitive Reason and Scientific Knowledge.

Each of these in one way or another involves affirmation or denial -- or their analogues in choice and avoidance (in practical matters) -- ways in which the person gets matters right.

There are several other states that Aristotle will discuss in Nicomachean Ethics book 6 as well. But, each of these states either is not a virtue, because the person possessing it does not necessarily get things right -- the case with Opinion and Assumption -- or it really is something falling under Practical Wisdom -- as with Understanding and Judgement, etc. He also distinguishes Practical Wisdom from Cleverness.