The soul is divided into reasoning power, anger and desire. Reasoning power rules knowledge, anger deals with impulse, and desire bravely rules the soul's affections. When these three parts unite into one action, exhibiting a composite energy, then in the soul results concord and virtue. When sedition divides them, then appear discord and vice. Virtue therefore contains three elements; reason, power, and deliberate choice. The soul's reasoning power's virtue is prudence, which is a habit of contemplating and judging. The irascible part's virtue is fortitude; which is a habit of enduring dreadful things, and resisting them. The appetitive part's virtue is temperance; which is a moderation and detention of the pleasures which arise from the body. The whole soul's virtue is justice; for men indeed become bad either through vice, or through incontinence, or through a natural ferocity. They injure each other either through gain, pleasure or ambition. More appropriately therefore does vice belong to the soul's reasoning part. While prudence is similar to good art, vice resembles bad art, inventing contrivances to act unjustly. Incontinence pertains to the soul's appetitive part, as continence consists in subduing, and incontinence in failure to subdue pleasures. Ferocity belongs to the soul's irascible part, for when some ennactivated by evil desires is gratified not as a man should be, but as a beast would be, then this is called ferocity.
The effects of these dispositions also result from the things for the sake of which they are performed. Vice, hailing from the soul's reasoning part results in avarice; the irascible part's fault is ambition, which results in ferocity; and as the appetitive part ends in pleasure, this generates incontinence. As unjust actions are the results of so many causes, so also are just deeds; for virtue is a naturally beneficent and profitable as vice is maleficent and harmful.
Since, however, of the parts of the soul one leads while the others follow, and since the virtues and vice subsist about these and in these, it is evident that with respect to the virtues also, some are leaders and others followers, while others are compounds of these. The leaders are such as prudence; the followers being fortitude and temperance; their composites are such as justice. How the virtues subsist in and about the passions, so we may call the latter the matter of the former. Of the passions, one is voluntary, and the others involuntary; pleasure being the voluntary, and pain the involuntary. Men who have the political virtues increase and decrease these, organizing the other parts of the soul to that which possesses reason. The desirable point of this adaptation is that intellect should not be prevented from accomplishing its proper work, either by lack of excess. We adapt the less good to that which is more so; as in the world every part that is always passive subsists for the sake of that which is always moved. In the conjunction of animals, the female subsists for the sake of the male; for the latter sows, generating a soul, while the former alone imparts matter to that which is generated. In the soul, the irrational subsists for the sake of the rational part. Anger and desire are organized in dependence on the first part of the soul, the former as a satellite and guardian of the body, the latter as a dispenser and provider of necessary wants. Intellect being established in the highest summit of the body, and having a prospect in that which is on all sides splendid and transparent, investigates the wisdom of real beings. This indeed is its natural function, to investigate and obtain possession of the truth, and to follow those beings which are more excellent and honorable than itself. For the knowledge of things divine and most honorable is the principle, cause and rule of human blessedness.
The principles of all virtue are three; knowledge, power and deliberate choice. Knowledge indeed is that by which we contemplate and form a judgment of things; power is a certain strength of nature from which we derive our subsistence, and which gives stability to our actions; and deliberate choice is as it were the hands of the soul by which we are impelled to, and lay hold on the objects of our choice...When the reasoning power prevails over the irrational part of the soul, then endurance and continence are produced; endurance indeed in the retention of pains, but continence in the absence of pleasures. But when the irrational parts of the soul prevail over the reasoning part of the soul, then are produced effeminacy in flying from pain, and incontinence in being vanquished by the pleasures. When however the better part of the soul prevails, the less excellent part is governed; the former leads, and the latter follows, and both consent and agree, and then in the whole soul is generated virtue and all the goods. Again, when the appetitive part of the soul follows the reasoning, then is produced temperance, when this is the case with the irascible, appears fortitude; and when it takes place in all the parts of the soul, then the result is justice. Justice is that which separates all the vices and all the virtues of the soul from each other. Justice is an established order and organization of the parts of the soul, and the perfect and supreme virtue; in this every good is contained, while the other goods of the soul cannot subsist without it. Hence justice possesses great influence both among gods and men. It contains the bond by which the whole and the universe are held together, and also that by which the gods and men are connected. Among the celestials it is called Themis, and among the terrestrials it is called Dice; while among men it is called the Law. These are but symbols indicative that justice is the supreme virtue. Virtue, therefore, when it consists in contemplating and judging, is called prudence; when in sustaining dreadful things, is called fortitude; when in restraining pleasure, it is called temperance; and when in abstaining from injuring our neighbors, justice.
Obedience to virtue according to, and transgression thereof contrary to right reason, tend towards decorousness, and its opposite. Propriety is that which ought to be. This requires neither addition or detraction, being what it should be. The improper is of two kinds: excess and defect. The excess is over -scrupulousness, and its deficiency, laxity. Virtue however is a habit of propriety. Hence it is both a climax and a medium of which are proper things. They are media because they fall between excess and deficiency; they are climaxes, because they endure neither increase nor decrease, being just what they ought to be.
Since however the virtue of manners consists in dealing with the passions, over which pleasure and pain are supreme, virtue evidently does not consist in extirpating the passions of the soul, pleasure and pain, but in regulating them. Not any more does health, which is an adjustment of the bodily powers, consist in expelling the cold and the hot, the moist and the dry, but in adjusting them suitably and symmetrically. Likewise in music, concord does not consist in expelling the sharp and the flat, but in exterminating dissonance by concord arising from their adjustment. Therefore it is the harmonious adjustment of heat and cold, moisture and dryness which produces health, and destroys disease. Thus by the mutual adjustment of anger and desire, the vices and other passions are extirpated, while virtue and good manners are induced. How the greatest peculiarity of the virtue of manners in beauty of conduct is deliberate choice. Reason and power may be used without virtue, but deliberate choice cannot be used without it; for deliberate choice inspires dignity of manners.
When the reasoning power by force subdues anger and desire, it produces continence and endurance. Again when the reasoning force is dethroned violently by the irrational parts, then result incontinence and effeminacy. Such dispositions of the soul as these are half-perfect virtues and vices. For (according to its nature) the reasoning power of the soul induces health, while the irrational induces disease. So far as anger and desire are governed and led by the soul's rational part, continence and endurance become virtues; but in so far as this is effected by violence, involuntarily, they become vices. For virtue must carry out what is proper not with pain but pleasure. So far as anger and desire rule the reasoning power there is produced effeminacy and incontinence, which are vices; but in so far as they gratify the passions with pain, knowing that they are erroneous in consequence of the eye of the soul being healthy, so far as this is the case, they are not vices. Hence it is evident that virtue must voluntarily do what is proper, as the involuntary implies pain and fear, while the voluntary implies pleasure and delight.
This may be corroborated by division. Knowledge and the perception of things are the province of the rational part of the soul; while power pertained to the irrational part, whose peculiarity is in an ability to resist pain, or to vanquish pleasure. Both of these, the rational and the irrational, subsists deliberate choice, which consists of intention and appetite, intention pertaining to the rational part, and appetite to the irrational. Hence every virtue consists in a mutual adaptation of the souls parts while, both will and deliberate choice subsist entirely in virtue. In general, therefore, virtue is a mutual [adaptation] of the irrational part of the soul to the irrational to the irrational. Virtue, however, is produced through pleasure and pain striking the right resultance of propriety. But propriety is that which ought to be, and the improper, what ought not;....... The fit and the unfit are to each other as the equal and the unequal, as the ordered and the disordered; of, which the two former are finite, and the two latter are the infinite (limit and infinity are the two great principles of things, below the universal ineffable cause). On this account the parts of the unequal are referred to the middle, but not to each other. An angle greater than a right angle is called obtuse; the acute one being less than it. (In a circle) also, the right line is greater than the radius, drawn from the centre. Any day beyond the equinox is greater is greater than it. Overheat or undercold produce diseases. Overheatedness exceeds moderation, which over-coldness does not reach.
The same analogy holds good in connection with the soul. Boldness is an excess of propriety in the endurance of things of a dreadful nature; while, timidity is a deficiency. Prodigality is an excess of proper expenditure of money; while illiberality is its excess. Rage is an excess of the proper use of the soul's irascible part, while insensibility ii the corresponding deficiency. The same reasoning applies to the opposition of the other dispositions of the soul. Since however virtue is a habit of propriety, and a medium of the passions, it should be neither wholly passive, nor immoderately passive. Impassivity causes unimpelledness of the soul and lack of enthusiasm for the beautiful in conduct, while immoderate passivity perturbs the soul, and makes it inconsiderate. We should then, in virtue, see passions as shadow and outline in a picture; which depend on animation and delicacy, imitation of the truth and contrast of coloring. The soul's passions are animated by the natural incitation and enthusiasm of virtue, which is generated from the passions, and subsisting with them. Similarly, harmony includes the sharp and the flat, and mixtures consist of heat and cold, and equilibrium results from weight and lightness.
Therefore, neither would it be necessary nor profitable to remove the passions of the soul: but they must be mutually adjusted to the rational part; under the direction of propriety and moderation.