But Greece did not introduce poetic beliefs only into Rome: she also caused her philosophy to be adopted there from the second century onwards, and this philosophy tended to be destructive both of those beliefs and of the old native faith in the Manes and in the Orcus. Polybius,[7] when speaking appreciatively of the religion of the Romans, praises them for having inculcated in the people a faith in numerous superstitious practices and tragic fictions. He considers this to be an excellent way of keeping them to their duty by the fear of infernal punishment. Hence we gather that if the historian thought it well for the people to believe in these inventions, then, in his opinion, enlightened persons, like his friends the Scipios, could see in them nothing but the stratagems of a prudent policy. But the scepticism of a narrow circle of aristocrats could not be confined to it for long when Greek ideas were more widely propagated. Greek philosophy made an early attack on the ideas held as to a future life. Even Democritus, the forerunner of Epicurus, spoke of “some people who ignore the dissolution of our mortal nature and, aware of the perversity of their life, pass their time in unrest and in fear and forge for themselves deceitful fables as to the time when follows their end.”[8] It is true that in the fourth century Plato’s idealism had supplied, if not a strict proof of immortality, yet reasons for it sufficient to procure its acceptance by such as desired to be convinced. But in the Alexandrian age, which was the surpassingly scientific period of Greek thought, there was a tendency to remove all metaphysical and mythical conceptions of the soul’s destiny from the field of contemplation. This was the period in which the Academy, Plato’s own school, unfaithful to its founder’s doctrines, was led by men who, like Carneades, raised scepticism to a system and stated that man can reach no certainty. We know that when Carneades was sent to Rome as ambassador in 156 B. C. he made a great impression by maintaining that justice is a matter of convention, and that he was consequently banished by the senate as a danger to the state. But we need only read Cicero’s works to learn what a lasting influence his powerfully destructive dialectics had. The dogmatism of other sects was at this time hardly at all more favourable to the traditional beliefs in another life.