And, as so often happens, that has proved a weakness and a strength to it: a weakness because embarrassed with subtle, complicated, insoluble questions wherein mankind will always be involved, it was forced to engage in endless discussions wherein the bad or feeble reasons advanced by this or that votary compromised the whole work; a strength because whoever brings a rule of life is practically compelled to support it by general ideas bearing on the relations of things and to give it a place in a general survey of the world; otherwise he appears impotent, weak, disqualified to give that very rule of life, incapable of replying to the interrogations raised by that rule of life; and finally, lacking in authority. SCHISMS AND HERESIES.--Right or wrong, and it is difficult and highly hazardous to decide the question, Christianity was a complete philosophy, which was why it had its schisms and heresies, a certain number of sincere Christians not resolving the metaphysical questions in the way of the majority. Heresies were innumerable; only the two shall be cited which are deeply interesting in the history of philosophy. Manes, an Arab (and Arabia was then a Persian province), revived the old Zoroastrian doctrine of two principles of good and evil, and saw in the world two contending gods, the God of perfection and the god of sin, and laid upon man the duty of assisting the God of goodness so that His kingdom should come and cause the destruction of evil in the world. From him proceeded the Manicheans, who exerted great influence and were condemned by many Councils until their sect died out, only to reappear or seem to reappear fairly often in the Middle Ages and in modern times. Arius denied the Trinity, believing only in one God, not only unique, but in one Person, and in consequence denied the divinity of Jesus Christ. He was perpetually involved in controversies and polemics, supported by some Bishops, opposed by the majority. After his death his doctrine spread strangely. It was stifled in the East by Theodosius, but was widely adopted by the "barbarians" of the West (Goths, Vandals, Burgundians, Lombards). It was revived, more or less exactly, after the Reformation, among the Socinians.