ONE:II.The greatest of Roman orators and writers was also the first Roman that held opinions of his own in philosophy. How much original thought occurs in his voluminous contributions to the literature of the subject is more than we can determine, the Greek authorities on which he drew being known almost exclusively through the references to them contained in his disquisitions. But, judging from the evidence before us, carefully sifted as it has been by German scholars, we should feel disposed to assign him a foremost rank among the thinkers of an age certainly not distinguished either for fertility or for depth of thought. It seems clear that he gave a new basis to the eclectic tendencies of his contemporaries, and that this basis was subsequently accepted by other philosophers whose speculative capacity has never been questioned. Cicero describes himself as an adherent of the New Academy, and expressly claims to have reasserted its principles after they had fallen into neglect among the Greeks, more particularly as against his own old master Antiochus, whose Stoicising theory of cognition he agrees with Philo in repudiating.269 Like Philo also, he bases certainty on the twofold ground of a moral necessity for acting on our beliefs,270 and the existence of moral intuitions, or natural tendencies to believe in the mind itself;271 or, perhaps, more properly speaking, on the single ground of a moral sense. This, as already stated, was unquestionably a reproduction of the Platonic ideas under their subjective aspect. But in his general views about the nature and limits171 of human knowledge, Cicero leaves the Academy behind him, and goes back to Socrates. Perhaps no two men of great genius could be more unlike than these two,��for us the most living figures in ancient history if not in all history,��the Roman being as much a type of time-servingness and vacillation as the Athenian was of consistency and resolute independence. Yet, in its mere external results, the philosophy of Socrates is perhaps more faithfully reproduced by Cicero than by any subsequent enquirer; and the differences between them are easily accounted for by the long interval separating their ages from one another. Each set out with the same eager desire to collect knowledge from every quarter; each sought above all things for that kind of knowledge which seemed to be of the greatest practical importance; and each was led to believe that this did not include speculations relating to the physical world; one great motive to the partial scepticism professed by both being the irreconcilable disagreement of those who had attempted an explanation of its mysteries. The deeper ground of man��s ignorance in this respect was stated somewhat differently by each; or perhaps we should say that the same reason is expressed in a mythical form by the one and in a scientific form by the other. Socrates held that the nature of things is a secret which the gods have reserved for themselves; while, in Cicero��s opinion, the heavens are so remote, the interior of the earth so dark, the mechanism of our own bodies so complicated and subtle, as to be placed beyond the reach of fruitful observation.272 Nor did this deprivation seem any great hardship to either, since, as citizens of great and free states, both were pre-eminently interested in the study of social life; and it is characteristic of their common tendency that both should have been not only great talkers and observers but also great readers of ancient literature.273