the Heracleitean theory in which the unity of Nature was conceived partly as a necessary interdependence of opposing forces, partly as a perpetual transformation of every substance into every other. Universal history also tended to confirm the same principle in its application to the human race. The Macedonian, and still more the Roman empire, brought the idea of a world-wide community living under the same laws ever nearer to its realisation; the decay of the old religion and the old civic patriotism set free a vast fund of altruism which now took the form of simple philanthropy; while a rank growth of immorality offered ever new opportunities for an indignant protest against senseless luxury and inhuman vice. This last circumstance, however, was not allowed to prejudice the optimism of the system; for the fertile physics of Heracleitus suggested a method by which moral evil could be interpreted as a necessary concomitant of good, a material for the perpetual exercise and illustration of virtuous deeds.[101] Yet, if the conception of unity was gaining ground, the conceptions of purpose and vitality must have been growing weaker as the triumph of brute force prolonged itself without limit or hope of redress. Hence Stoicism in its later form shows a tendency to dissociate the dynamism of Heracleitus from the teleology of Socrates, and to lean on the former rather than on the latter for support. One symptom of this changed attitude is a blind worship of power for its own sake. We find the renunciation of pleasure and the defiance of pain appreciated more from an aesthetic than from an ethical point of view; they are exalted almost in the spirit of a Red Indian, not as means to higher ends, but as manifestations of unconquerable strength; and sometimes the highest sanction of duty takes the form of a morbid craving for applause, as if the universe were an amphitheatre and life a gladiatorial game.[102]