The performance of a particular act is easy.  To perform it rightly as the outcome of a right habit, is not; nor is it easy to be confident as to what is right in the particular case.  The man who is just, having the habit, does not find it easy to act unjustly.

What we must call equity may be opposed to justice, but only in the legal sense of that term.  It is justice freed from the errors incidental to the particular case, for which the law cannot provide.  Injustice, again, is found in self-injury or suicide; which the law penalises, not because the individual thereby treats himself unjustly, but because he does an injustice to the community.  It is only by metaphor that a man may be called unjust to himself, an expression which means that the relation between one part of him and another part of him is analogous to the unjust relation between persons.

IV.—­WISDOM, PRUDENCE AND CONTINENCE

The ensuing discussion of intellectual virtue requires some remarks on the soul.  We distinguish in the rational part, that which knows, concerned, with the unchanging; and that which reasons, concerned with the changing.  Our intellects and our propensions—­not our sense-perceptions, which are shared with animals—­guide our actions and our apprehension of truth.  Attraction and repulsion, in correspondence with affirmation and denial, combine to form right choice; the practical—­as opposed to the pure—­reason having an external object, and being a motive power.

There are five modes of attaining truth:  (1) Concerning things unalterable, defined as demonstrative science; (2) concerning the making of things changeable, art; (3) concerning the doing—­not making—­of things changeable, prudence; (4) intuitive reason, the basis of demonstrative science; (5) wisdom, the union of intuitive reason and science.

Wisdom and prudence are the two virtues of the intellect.  Wisdom implies intuitive reason, which grasps undemonstrable first principles; it is concerned with the interests not of the moment, the individual, or the locality.  Whereas prudence is concerned precisely with these; it is essentially practical.  Wisdom cannot be identified with statesmanship; which, again, is not the same as prudence—­which applies to the self, and to the family, as well as to the State; it differs from wisdom as requiring experience.

Wisdom, knowledge of the ultimate bases, is equally without practical bearing for those who have acquired a right habit and for those who have not; just as a knowledge of medical theory is of no use to the average man.  But being an activity of the soul, ipso facto, it conduces to happiness.  The general conclusion is that what we have called “prudence” shows the means to the end which the moral virtues aim at.  It is not a moral virtue, but the moral virtues accord with it.  Both are necessary to the achievement of goodness.

We come now to a second group of qualities, concerned with conduct.  We have dealt with the virtues and their opposing vices.  We pass by the infra-human and the supra-human bestiality and holiness; but have still to deal with Continence and its contrasted qualities, which are concerned with the passions.