genera.[2] This psychological illusion as to the existence of ideas for types originates (as we find elsewhere in Schopenhauer) in the habit of converting the empirical classifications of the natural sciences into living realities. "Do you wish to see ideas?" he asks; "look at the clouds which scud across the sky; look at a brooklet leaping over rocks; look at the crystallization of hoar-frost on a window-pane with its designs of trees and flowers. The shapes of the clouds, the ripples of the gushing brook, the configurations of the crystals exist for us individual observers, in themselves they are indifferent. The clouds in themselves are elastic vapour; the brook is an incompressible fluid, mobile, transparent, amorphous, the ice obeys the laws of crystallization: and in these determinations their ideas consist."[3] All these are the immediate objectification of will in its various degrees; and it is these, not their pale copies in real things, that art delineates; whence Plato was right in one sense and wrong in another, and is justified and condemned by Schopenhauer exactly in the same way as by Plotinus of old, as well as by Schopenhauer's worst enemy, the modern Schelling.[4] In consequence, each art has a special category of ideas for its own dominion. Architecture, and in some cases hydraulics, facilitate the clear intuition of those ideas which constitute the lower degrees of objectification--weight, cohesion, resistance, hardness, the general properties of stone and some combinations of light; gardening and (most curious association) landscape painting represent the ideas of vegetable nature; sculpture and animal painting those of zoology; historical painting and the higher forms of sculpture that of the human body; poetry the very idea of man himself.[5] As for music, that (let him who can justify the logical discontinuity) is outside the hierarchy of the other arts. We have seen how Schelling considered it to be representative of the very rhythm of the universe;[6] differing but slightly from this, Schopenhauer affirms that music does not express ideas but, parallel with ideas, Will itself. The analogies between music and the world, between the fundamental bass and crude matter, between the scale and the series of species, between melody and conscious will, led him to the conclusion that music was not, as Leibniz thought, an arithmetic but a metaphysic: _exercitium metaphysices occultum nescientis se philosophari animi_.[7] [Sidenote: _Æsthetic catharsis._] To Schopenhauer, no less than his idealistic predecessors, art beatifies; it is the flower of life; he who contemplates art is no longer an individual but a pure knowing subject, at liberty, free from desire, from pain, from time.[8] [Sidenote: _Signs of a better theory in Schopenhauer._]