Man [he said] is free to do good or evil: he who tries to lay the blame of his vices on the weakness of nature, is unjust: for what is sin, in general? Is it a thing that one may evade, or not? If one cannot evade it, there is no evil in committing it and then it does not exist: if one can evade it, it must be evil to commit it and therefore it exists: its very existence is born of the free will, and proves it.[618] The dogma of original sin [continued Pelagius] is absurd and unjust to God; for a creature which does not exist would not be an accomplice of a bad action; and it outrages divine justice, to say that God punishes him as guilty of this action.[619] Man [added Pelagius] has therefore a real power of doing good and evil, and he is free in these two respects. But the liberty of doing a thing supposes necessarily the union of all causes and of all conditions requisite for doing that thing; and one is not free regarding an effect, every time that one of the causes or conditions naturally exigent for producing this effect is lacking. Therefore, to have the liberty of seeing the subjects, it is necessary not only that the sense of sight be well developed, but also that the subjects be discriminated, and placed at an equitable distance.[620] This far, the doctrine of Pelagius was wholly similar to that of Pythagoras, as explained by Hierocles[621]; but it differs from it afterwards, in what the English monk asserted, that since man is born with the liberty of doing good and evil, he receives from nature and unites in him all the conditions and all the causes naturally necessary for good and evil; which robs him of his most beautiful prerogative,――perfectibility; whereas Pythagoras held, on the contrary, that these causes and these effects were only accorded to those who, on their part, concurred in acquiring them, and who, by the work that they have done for themselves in seeking to know themselves, have succeeded in possessing them more and more perfectly.