Plutarch, De virtute morali
W. C. Helmbold, Ed.

But inasmuch as philosophers do not make virtue as a whole a mean nor apply to it the term ‘moral,’ we must discuss the difference, starting with first principles. Now in this world things [p. 37] are of two sorts, some of them existing absolutely, others in some relation to us. Things that exist absolutely are earth, heavens, stars, sea ; things that exist in relation to us are good and evil, things desirable and to be avoided, things pleasant and painful. Now reason¹ contemplates both of these, but when it is concerned merely with things which exist absolutely, it is called scientific and contemplative ; and when it is engaged with those things which exist in relation to us, it is called deliberative and practical. The virtue of the latter activity is called prudence, that of the former wisdom ; and prudence differs from wisdom in that when the contemplative faculty is occupied in a certain active relationship with the practical and passionate, prudence comes to subsist in accordance with reason. Therefore prudence² has need of chance, but wisdom has no need of it, nor yet of deliberation, to attain its proper end ; for wisdom is concerned with things that remain ever the same and unchanging. And just as the geometer does not deliberate whether the triangle has its internal angles equal to two right angles, but knows it to be true (for deliberation concerns matters that are now one way, now another, not things that are sure and immutable), just so the contemplative mind has its activity concerning first principles, things that are permanent and have ever one nature incapable of mutation, and so has no occasion for deliberation. But prudence must often come down among things that are material and are full of error and confusion ; it has to move in the realm of chance ; to deliberate where [p. 39] the case is doubtful; and then at last to reduce deliberation to practice in activities in which decisions are both accompanied by and influenced by the irrational, whose impulsion they, as a matter of fact, need. The impulsion of passion springs from moral virtue ; but it needs reason to keep it within moderate bounds and to prevent its exceeding or falling short of its proper season. For it is indeed true that the passionate and irrational moves sometimes too violently and swiftly, at other times more weakly and slothfully than the case demands. Therefore everything that we ever do can succeed but in one way, while it may fail in many ways³: for to hit the mark there is but one single, uncomplicated, way, yet it can be missed in several ways, according to whether we exceed the mean, or fall short of it. This, then, is the natural task of practical reason : to eliminate both the defects and the excesses of the passions. For wherever, through infirmity and weakness, or fear and hesitation, the impulsion yields too soon and prematurely forsakes the good,⁴ there practical reason comes on the scene to incite and rekindle the impulsion; and where, again, the impulsion is borne beyond proper bounds, flowing powerfully and in disorder, there practical reason removes its violence and checks it. And thus by limiting the movement of the passions reason implants in the irrational the moral virtues, which are means between deficiency and excess. For we must not declare that every virtue comes into being by the observance of a mean, but, on the one hand, wisdom, being without any [p. 41] need of the irrational and arising in the activity of the mind, pure and uncontaminated by passion, is, as it were, a self-sufficing perfection and power⁵ of reason, by which the most divine and blessed element of knowledge becomes possible for us ; on the other hand, that virtue which is necessary to us because of our physical limitations, and needs, by Heaven, for its practical ends the service of the passions as its instrument, so to speak, and is not a destruction nor abolition of the irrational in the soul, but an ordering and regulation thereof, is an extreme as regards its power and quality, but as regards its quantity it is a mean, since it does away with what is excessive and deficient.