A number of fathers say that humanity was responsible for the creation of evil. For example:
"[Man] himself became the inventor of evil; he did not come across it as something already created by God. For God did not make death; it was man who became, so to speak, the originator and creator of evil." - St. Gregory of Nyssa, On Virginity, 12
Yet wasn't Satan evil before man's fall, and didn't Satan introduce evil into the world? In Genesis it says that the serpent was "subtil" or "crafty," (Gen. 3:1) and the serpent tricked Adan and Eve into eating of the tree and therefore disobeying God (Gen. 3:1-7). Wouldn't this bit of trickery mean that Satan was the creator of evil in this world? Also, wouldn't the very fact that Satan was on the earth at that point demonstrate that he had already fallen from his place in heaven, and had therefore introduced pride and evil into God's creation?