With regard to ethics, there is, of course, a great difference between the innovating, creative genius of the Greek and the receptive but timid intelligence of the Roman. Yet the uncertainty which, in the one case, was due to the absence of any fixed system, is equally present in the other, owing to the embarrassment of having so many systems among which to choose. Three ethical motives were constantly present to the thoughts of Socrates: the utility of virtue, from a material point of view, to the individual; its social necessity; and its connexion with the dual constitution of man as a being composed of two elements whereof the one is infinitely superior to the other; but he never was able, or never attempted to co-ordinate them under a single principle. His successors tried to discover such a principle in the idea of natural law, but could neither establish nor apply it in a satisfactory manner. Cicero reproduces the Socratic elements, sometimes in their original dispersion and confusion, sometimes with the additional complication and perplexity introduced by the idea through which it had been hoped to systematise and reconcile them. To him, indeed, that idea was even more important than to the Greek moralists; for he looked on Nature as the common ground where philosophy and untrained experience might meet for mutual confirmation and support.[274] We have seen how he adopted the theory—as yet not very clearly formulated—of a moral sense, or general faculty of intuition, from Philo. To study and obey the dictates of this faculty, as distinguished from the depraving influence of custom, was his method of arriving at truth and right. But if, when properly consulted, it always gave the same response, a similar unanimity might be expected in the doctrines of the various philosophical schools; and the adhesion of Academicians, Peripatetics, and Stoics to the precept, Follow Nature, seemed to demonstrate that such an agreement actually existed. Hence Cicero over and over again labours to prove that their disputes were merely verbal, and that Stoicism in particular had borrowed its ethics wholesale from his own favourite sect. Yet from time to time their discrepancies would force themselves on his notice; and by none have the differences separating Stoicism from its rivals been stated with more clearness, concision, and point.[275] These relate to the absolute self-sufficingness of virtue, its unity, and the incompatibility of emotion with its exercise. But Cicero seems to have regarded the theory of preference and rejection as a concession to common sense amounting to a surrender of whatever was parodoxical and exclusive in the Stoic standpoint.[276] And with respect to the question round which controversy raged most fiercely, namely, whether virtue was the sole or merely the chief condition of happiness, Cicero, as a man of the world, considered that it was practically of no consequence which side prevailed.[277] It