Evil is therefore the absence of what ought to be there. Physical evil is the privation of a natural good desired by a human being. It is the absence of some satisfaction desired by a human appetite, whether spiritual or bodily. In general, it may be equated with pain. It is the loss or deprivation of what a person wants.
Moral evil is sin, as distinct from physical evil, which is some form of suffering.
The Council of Trent condemned the contrary doctrine. God simply permits moral evil because of consideration of human freedom, and because He has the wisdom and power to cause good to arise from evil. In the end, moral evil will serve the supreme purpose of the universe, the glorification of God, since it reveals both His mercy in forgiving and His justice in punishing. The most comprehensive list of good Catholic books is contained in The Catholic Lifetime Reading Plan. Originally published by Doubleday, the book is now out of print.