[(1) Its relation to cotemporary dogmatic systems.] as the cotemporary dogmatic systems, the post-Aristotelian Scepticism takes a practical view of the business of philosophy, and estimates the value of theoretical enquiries by their influence on the state and happiness of man. It moreover agrees with cotemporary systems in its ethical view of life; the object at which it aims is the same as that at which those systems aim, viz. repose of mind, and imperturbability. It differs from them, none the less; for the Epicureans and Stoics made mental repose to depend on a knowledge of the world and its laws, whereas the Sceptics are of opinion that it can only be obtained by despairing of all knowledge. Hence, with the former morality depends on a positive conviction as to the highest Good; with the latter, morality consists in indifference to all that appears as Good to men. Important as this difference may be, it must not therefore be forgotten that Scepticism generally revolves in the same sphere as Stoicism and Epicureanism, and that in renouncing all claim to knowledge, and all interest in the external world, it is only pushing to extremes that withdrawal of man into himself which we have seen to be the common feature of these Schools. Not only, therefore, do these three lines of thought belong to one and the same epoch, but such is their internal connection that they may be regarded as three branches of a common stock. [(2) Causes producing it.] More than one point of departure was offered to Scepticism by the earlier philosophy. The Megarian criticism and the Cynic teaching had taken up a position subversive of all connection of ideas, and of all knowledge. Pyrrho, too, had received from the School of Democritus an impulse to doubt. [1382] In particular, the development of the Platonic and Aristotelian speculations by those who were not able to follow them, had made men mistrustful of all speculation, until they at last doubted the possibility of all knowledge. Not seldom do Sceptical theories follow times of great philosophical originality. A stronger impulse was given in the sequel by the Stoic and Epicurean systems. Related to Scepticism by their practical tone, it was natural that these systems should afford fuel to Scepticism. At the same time the unsatisfactory groundwork upon which they were built, and the contrast between their moral and physical teaching, promoted destructive criticism. If, according to the Stoics and Epicureans, the particular and the universal elements in the personal soul, the isolation of the individual as an independent atom, and his being merged in a pantheistic universe, are contrasted without being reconciled; among the Sceptics this contrast has given place to neutrality. Neither the Stoic nor the Epicurean theory can claim our adherence; neither the unconditional value of pleasure, nor yet the unconditional value of virtue; neither the truth of the senses nor the truth of rational