THREE:We cannot, then, agree with Zeller, when he groups the292 Neo-Platonists together with the other post-Aristotelian schools, on the ground that they are all alike distinguished from Plato and Aristotle by the exclusive attention which they pay to subjective and practical, as opposed to scientific and theoretical interests. It seems to us that such distinctions are out of relation to the historical order in which the different systems of Greek philosophy were evolved. It is not in the substance of their teaching, but in their diminished power of original speculation, that the thinkers who came after Aristotle offer the strongest contrast to their predecessors. In so far as they are exclusively practical and subjective, they follow the Humanists and Socrates. In so far as they combine Socratic tendencies with physical studies, they imitate the method of Plato and Aristotle. Their cosmopolitan naturalism is inherited from the Cynics in the first instance, more remotely from the physiocratic Sophists, and, perhaps, in the last resort, from Heracleitus. Their religion is traceable either to Pythagoras, to Socrates, or to Plato. Their scepticism is only a little more developed than that of Protagoras and the Cyrenaics. But if we seek for some one principle held in common by all these later schools, and held by none of the earlier schools, we shall seek for it in vain. The imitative systems are separated from one another by the same fundamental differences as those which divide the original systems. Now, in both periods, the deepest of all differences is that which divides the spiritualists from the materialists. In both periods, also, it is materialism that comes first. And in both, the transition from one doctrine to the other is marked by the exclusive prominence given to subjective, practical, sceptical, or theological interests in philosophy; by the enthusiastic culture of rhetoric in general education; and by a strong religious reaction in the upper ranks of society.The simple dread of death, considered as a final annihilation of our existence, remained to be dealt with. There was no part of his philosophy on which Epicurus laid so much stress; he regarded it as setting the seal on those convictions, a firm grasp of which was essential to the security of human happiness. Nothing else seemed difficult, if once the worst enemy of our tranquillity had been overcome. His argument is summed up in the concise formula: when we are, death is not; when death is, we are not; therefore death is nothing to us.175 The pleasures of life will be no loss, for we shall not feel the want of them. The sorrow of our dearest friends will be indifferent to us in the absence of all consciousness90 whatever. To the consideration that, however calmly we may face our own annihilation, the loss of those whom we love remains as terrible as ever, Lucretius replies that we need not mourn for them, since they do not feel any pain at their own extinction.176