The ancient Greek schools were, properly speaking, only two, and in determining the conception of the summum bonum these followed in fact one and the same method, inasmuch as they did not allow virtue and happiness to be regarded as two distinct elements of the summum bonum, and consequently sought the unity of the principle by the rule of identity; but they differed as to which of the two was to be taken as the fundamental notion. The Epicurean said: "To be conscious that one's maxims lead to happiness is virtue"; the Stoic said: "To be conscious of one's virtue is happiness." With the former, Prudence was equivalent to morality; with the latter, who chose a higher designation for virtue, morality alone was true wisdom. While we must admire the men who in such early times tried all imaginable ways of extending the domain of philosophy, we must at the same time lament that their acuteness was unfortunately misapplied in trying to trace out identity between two extremely heterogeneous notions, those of happiness and virtue. But it agrees with the dialectical spirit of their times (and subtle minds are even now sometimes misled in the same way) to get rid of irreconcilable differences in principle by seeking to change them into a mere contest about words, and thus apparently working out the identity of the notion under different names, and this usually occurs in cases where the combination of heterogeneous principles lies so deep or so high, or would require so complete a transformation of the doctrines assumed in the rest of the philosophical system, that men are afraid to penetrate deeply into the real difference and prefer treating it as a difference in questions of form. {BOOK_2|CHAPTER_2 ^paragraph 5}