The practice of the libertine is to identify pleasure and good in such a manner that he pursues at any moment any pleasure that presents itself, eschewing comparison and reflection, with all that might tend to check that continuous flow of vivid and fresh sensations which he postulates as the end of life. The ideal of the Greeks, on the contrary, as interpreted by their two greatest thinkers, while on the one hand it is so far opposed to asceticism that it requires pleasure as an essential complement of Good, on the other, is so far from identifying the two, that it recognises an ordered scale of pleasures, and while rejecting altogether those at the lower end, admits the rest, not as in themselves constituting the Good, but rather as harmless additions or at most as necessary accompaniments of its operation. Plato, in the Republic, distinguishes between the necessary and unnecessary pleasures, defining the former as those derived from the gratification of appetites "which we cannot get rid of and whose satisfaction does us good"--such, for example, as the appetite for wholesome food; and the latter as those which belong to appetites "which we can put away from us by early training; and the presence of which, besides, never does us any good, and in some cases does positive harm,"--such, for example, as the appetite for delicate and luxurious dishes. [Footnote: Plato, Rep. VIII. 558.--Translated by Davies and Vaughan.] The former he would admit, the latter he excludes from his ideal of happiness. And though in a later dialogue, the Philebus, he goes further than this, and would exclude from the perfect life all pleasures except those which he describes as "pure," that is those which attend upon the contemplation of form and colour and sound, or which accompany intellectual activity; yet here, no doubt, he is passing beyond the sphere of the practicable ideal, and his distinct personal bias towards asceticism must be discounted if we are to take him as representative of the Greek view. His general contention, however, that pleasures must be ranked as higher and as lower, and that at the best they are not to be identified with the Good, is fully accepted by so typical a Greek as Aristotle. Aristotle, however, is careful not to condemn any pleasure that is not definitely harmful. Even "unnecessary" pleasures, he admits, may be desirable in themselves; even the deliberate creation of desire with a view to the enjoyment of satisfying it may be admissible if it is not injurious. Still, there are kinds of pleasures which ought not to be pursued, and occasions and methods of seeking it which are improper and perverse. Therefore the Reason must be always at hand to check and to control; and the ultimate test of true worth in pleasure, as in everything else, is the trained judgment of the good and sensible man. Section 7. Illustrations--Ischomachus; Socrates.