be impossible unless we were in a position to compare them with the corresponding truths.[257] For his own part, Antiochus adopted without alteration the empirical theory of Chrysippus, according to which knowledge is elaborated by reflection out of the materials supplied by sense. His physics were also those of Stoicism with a slight Peripatetic admixture, but without any modification of their purely materialistic character. In ethics he remained truer to the Academic tradition, refusing to follow the Stoics in their absolute isolation of virtue from vice, and of happiness from external circumstances, involving as it did the equality of all transgressions and the worthlessness of worldly goods. But the disciples of the Porch had made such large concessions to common sense by their theories of preference and of progress, that even here there was very little left to distinguish his teaching from theirs.[258] Meanwhile a series of Stoic thinkers had also been feeling their way towards a compromise with Plato and Aristotle, which, so far as it went, was a step in the direction of spiritualism. We have seen, in a former chapter, how one of the great distinguishing marks of Stoicism, as compared with the systems immediately preceding it, was the substitution of a pervading monism for their antithesis between God and the world, between heaven and earth, between reason and sense. It will be remembered also that this monistic creed was associated with a return to the Heracleitean theory that the world is periodically destroyed by fire. Now, with reference to three out of these four points, Boêthus, a Stoic contemporary of Carneades, returned to the Aristotelian doctrine. While still holding to the materialism of his own school, including a belief in the corporeal nature of the divinity, he separated God from the world, and represented him as governing its movements from without; the world itself he maintained to be eternal; and in the mind of man he recognised reason or nous as an independent source of conviction. In his cosmology, Boêthus was followed by a more celebrated master, Panaetius, who also adopted the Aristotelian rationalism so far as to deny the continued existence of the soul after death, and to repudiate the belief in divination which Stoicism had borrowed from popular superstition; while in psychology he partially restored the distinction between life and mind which had been obliterated by his predecessors.[259] The dualistic theory of mind was carried still further by Posidonius, the most eminent Stoic of the first century B.C. This very learned and accomplished master, while returning in other points to a stricter orthodoxy, was led to admit the Platonic distinction between reason and passion, and to make it the basis of his ethical system.[260] But the Platonising tendencies of Posidonius had no more power than those of Antiochus to effect a true spiritualistic revival, since neither they nor any of their