Yet let no one ask, “How was it that, if God foresaw the misfortune that would happen to man from want of thought, He came to create him, since it was, perhaps, more to his advantage not to have been born than to be in the midst of such evils?” This is what they who have been carried away by the false teaching of the Manichees put forward for the establishment of their error, as thus able to show that the Creator of human nature is evil. For if God is not ignorant of anything that is, and yet man is in the midst of evil, the argument for the goodness of God could not be upheld; that is, if He brought forth into life the man who was to be in this evil.
For if the operating force which is in accordance with the good is entirely that of a nature which is good, then this painful and perishing life, they say, can never be referred to the workmanship of the good, but it is necessary to suppose for such a life as this another author, from whom our nature derives its tendency to misery. Now all these and the like assertions seem to those who are thoroughly imbued with the heretical fraud, as with some deeply ingrained stain, to have a certain force from their superficial plausibility.
But they who have a more thorough insight into the truth clearly perceive that what they say is unsound, and admits of speedy demonstration of its fallacy. In my opinion, too, it is well to put forward the Apostle as pleading with us on these points for their condemnation. In his address to the Corinthians he makes a distinction between the carnal and spiritual dispositions of souls; showing, I think, by what he says that it is wrong to judge of what is morally excellent, or, on the other hand, of what is evil, by the standard of the senses; but that, by withdrawing the mind from bodily phenomena, we must decide by itself and from itself the true nature of moral excellence and of its opposite.
“The spiritual man,” he says, “judges all things.” This, I think, must have been the reason of the invention of these deceptive doctrines on the part of those who propound them, viz. that when they define the good they have an eye only to the sweetness of the body's enjoyment, and so, because from its composite nature and constant tendency to dissolution that body is unavoidably subject to suffering and sicknesses, and because upon such conditions of suffering there follows a sort of sense of pain, they decree that the formation of man is the work of an evil deity.
Since, if their thoughts had taken a loftier view, and, withdrawing their minds from this disposition to regard the gratifications of the senses, they had looked at the nature of existing things dispassionately, they would have understood that there is no evil other than wickedness. Now all wickedness has its form and character in the deprivation of the good; it exists not by itself, and cannot be contemplated as a subsistence. For no evil of any kind lies outside and independent of the will; but it is the non-existence of the good that is so denominated.
Now that which is not has no substantial existence, and the Maker of that which has no substantial existence is not the Maker of things that have substantial existence. Therefore the God of things that are is external to the causation of things that are evil, since He is not the Maker of things that are non-existent. He Who formed the sight did not make blindness. He Who manifested virtue manifested not the deprivation thereof. He Who has proposed as the prize in the contest of a free will the reward of all good to those who are living virtuously, never, to please Himself, subjected mankind to the yoke of a strong compulsion, as if he would drag it unwilling, as it were his lifeless tool, towards the right.
But if, when the light shines very brightly in a clear sky, a man of his own accord shuts his eyelids to shade his sight, the sun is clear of blame on the part of him who sees not.
Source: The Great Catechism (New Advent)