Comme les enfants
I'm 16, and an atheist, and one day I asked myself the following:
'Why is there evil? If the god portrayed by Christians, Catholics and various other religions is so "benevolent" and "forgiving", why does evil happen?'
This is a very complex question; there is an entire theological and philosophical field, theodicy, that aims to answer this question. There are a number of different answers to this question, all of which have varying degrees of theological significance.
The most common answers to these questions, when one looks at Christianity and Catholicism, include that God allows evil to occur to maintain humanity's free will. Humans have the right to do good or bad, allowing God to judge them based on their actions. If humans could not do evil, then on what basis can God judge humanity? This arguments suffers from serious issues, however. Christianity believes God to be omniscient and omnipotent. If God is all-knowing and all-powerful, God would not only know how an individual would react in a given situation (i.e., their capacity to do evil) and has the ability to choose to create a reality in which that person does not do evil. If God knows what someone will do already, why is evil required to know their capacity to do it? And God created this reality where He chose which specific people are capable of doing certain evil actions, making God ultimately responsible for who gets into heaven. This argument falls flat.
Another is that life is a test of one's ability to do good or evil, and whether or not one goes to Heaven or Hell can be seen, if we extend the metaphor, as the passing or failing grade. Job is often cited to justify this interpretation of God's use of evil, Satan acting as a divine test-giver whose job is to make sure you have no way of passing, so to speak. The problem with this argument is that, for life to be a proper and reliable test of one's ability to do evil, it has to be fair; everybody must be born and live with the same conditions, the only independent variable being the individual themselves, for a test to be a fair assessment. The Amazing Atheist, a man that, while I have grown to dislike, I think argues this point better than I could, had this to say:
"Imagine that you're a fourth grader and your teacher has just handed out a test to all the students in your classroom. With each paper she hands out, she tells people how much time they have to take the test. Some kids are expected to do it in 15 minutes, and others are told they can turn it in next week. Some tests are long, and others are short. Some have easy questions like '3 + 4 = what?," and others have difficult questions like 'What were the three main points advanced by Edmund Burke in his 1791 work Thoughts on French Affairs?' Would anyone take the results of such a test seriously?" This is the most accurate equivalence one can make between any kind of a test and real life.
Some argue that evil is nothing more than the absence of good. This argument is interesting, and I enjoy it. I have no comments; I just thought you'd like it.
Then there is the classic that evil comes through the works of Satan in an attempt to get others to sin to make them go to Hell. The problem with this, I think, is obvious. If God is omnipotent, can God not destroy Satan, thereby ridding us of evil? Can God not show 100% undeniable proof of His existence so that Satan cannot tempt humanity to do sinful things under the guise that God does not exist? However, this answer often goes hand-in-hand with the free will argument of evil.