634. Why does evil exist in the nature of things? I am speaking of moral evil. Couldn’t God have created the human race under more favorable conditions?
“We have already told you that when spirits are created they are simple and ignorant (see no. 115). God leaves all human beings free to choose their own path; too bad for them if they choose the wrong one, their journey will be longer. If there were no mountains, humans could not grasp the concept of climbing uphill and descending. If there were no rocks, they could not understand the concept that hard bodies exist. Spirits must acquire experience, and to do this properly they must know both good and bad. This is why there is an union of spirit and body.” (See no. 119)