This relationship is more strikingly seen in the way in which they deal with the practical problem. The Epicurean imperturbability is akin to that of the Sceptics; both resemble the Stoic apathy. All three Schools are agreed that the only way to happiness consists in peace of mind, and in avoiding all those disturbances which sometimes arise from external influences, at other times from internal emotions; they are only divided as to the means by which peace of mind may be secured. They are also agreed in making moral activity independent of external circumstances, and in separating morals from politics, although only the Stoics set up the doctrine of the original unity of the whole human family, and insist on being citizens of the world. Through all the Schools runs the common trait of referring everything to the subject, and constantly falling back on man and his own inner life, one consequence of which is the prominence given to action in preference to speculation, and another that action is determined by personal certainty, and a mental equilibrium which must be attained by the exercise of will and the cultivation of the intellect. [(3) Their peculiarities illustrated by subsequent philosophy.] The same character belongs to philosophy in the centuries succeeding the rise of these three Schools; during which the circumstances which produced that character were not materially altered. In addition to the followers of the old Schools, Eclectics are now met with, who gather from every system what seems true and probable. In this process of selection their guiding principle is regard for the practical wants of man. Hence the ultimate standard of truth is placed in personal consciousness. Everything is referred to the subject as its centre. In ethics and natural theology the Eclectics were mainly indebted to the Stoics. A new School of Sceptics also arose, not differing in its tendencies from the older one. Neopythagoreans and Platonists appeared, not satisfied with human knowledge, but aspiring to higher revelations. Professing to appeal to the metaphysics of Plato and Aristotle, these philosophers betray their connection with the later post-Aristotelian Schools, not only by borrowing largely from the Stoics for the material for their theology and ethics, but also by their general tone; knowledge is for them less even than for the Stoics an end in itself, and they are further from natural science. With them philosophy is subservient to the interests of religion; its aim is to bring men into proper relation with God; and the religious needs of mankind are the highest authority for science.