(_αα_) The doctrine of the purification of the passions shares in the defect previously noted as adhering to the mitigation of desires. It does, however, emphasize more closely the fact that the representations of art needed a standard, by means of which it would be possible to estimate their comparative worth and unworth. This standard is just their effectiveness to separate what is pure from that which is the reverse in the passions. Art, therefore, requires a content which is capable of expressing this purifying power, and in so far as the power to assert such effectiveness is assumed to constitute the substantive end of art, the purifying content will consist in asserting that effective power before consciousness in its _universality_ and _essentiality._[96] (_ββ_) It is a deduction from the point of view just described that it is the end of art to _instruct._ Thus, on the one hand, the peculiar character of art consists in the movement of the emotions and in the satisfaction which is found in this movement, even in fear, compassion, in painful agitation and shock--that is to say, in the satisfying concern of the feelings and passions, and to that extent in a complacent, delighted, or enthusiastic attitude to the objects of art and their presentation and effect: while, on the other hand, this artistic object is held to discover its higher standard exclusively in its power to instruct, in the _fabula docet_, and thereby in the usefulness, which the work of art is able to exercise on the recipient. In this respect the Horatian adage Et prodesse volunt et delectare poetae[97] contains, concentrated into a few words, all that in after times has been drawn out as a doctrine of art through every conceivable grade of dilution to the last extreme of insipidity. In respect, then, to such instruction we have to ask whether the idea is that the same ought to be direct or indirect in the work of art, explicit or implicit. Now if the question at issue is one of general importance to art about a universal rather than contingent purpose, such an ultimate end, on account of the essential spirituality of art, can only be itself of spiritual import; in other words, so far from being of accidental importance it must be true in virtue of its own nature and on its own account. An end of this kind can only apply to instruction in so far as a genuine and essentially explicit content is brought before the mind by means of the work of art. From such a point of view we are entitled to affirm that it is the function of art to accept so much the more of a content of this nature within its compass in proportion to the nobility of its rank, and that only in the verity of such a content will it discover the standard according to which the pertinency of or the reverse of what is expressed is adjudged. Art is in truth the primary[98] _instructress_ of peoples.