To me, defining evil is very much like trying to define one word only to have to use another which likely needs definition. It becomes one of those endless dictionary quests in which each definition contains a harder word which then must be looked up. The result of this pursuit is that the very best I could bring myself to do would be to phrase the definition of evil in logistical statements. Beyond this, and I guess something which I should get used to as a philosophy student, is providing my own personal opinion as to what for me constitutes evil. Providing such a personal definition is possible at least, even though it is barely any less complicated than the logic puzzle would be.
On top of being complicated, the endeavor is bound to make me feel like a scab, for as one who wishes to take all situations and points of view into fair consideration, placing something in such black and white terms feels like a betrayal. However, education is nothing if not intended to be challenging, and so I am choosing to challenge myself to define “evil.” First, though, before being able to define evil and relate it to the implications of the mortal pursuit of proving God's existence or not, I must examine my feelings on whether or not mortals can come up with such a proof.
The idea of God was created out of the need to feel there was something bigger than ourselves. Those things which humans did not know, could not figure out, or could not even conceive of, could all then be set aside as knowledge only within the realm of God's understanding. Humans did not know where they came from or why they were here, but by placing God in the position of creator, it was possible to believe that he knew the answers to these questions, and that he had a reason for everything - though we didn't know it ourselves. Kierkegaard made the argument that trying to use rational thought to conceive of and prove the actuality of God is not one fairly made.
Whether any individual believes this to be true or not, in coming to a decision on this subject, it is now first necessary to examine what rationality is to begin with. (And the dictionary search continues to get more complicated.) Rationale's most simple definition paraphrased is “based in logic”. Logic is the natural workings of the human brain towards finding solution or course of action. Therefore, to do something rationally, we must first use our minds. What a mind is, and how it works exactly, is another unanswerable question.
Where the chips of this debate fall, is in combining the fact that rational thought is produced by the brain, and the brain (according to many) was created by God, and that what makes God in the first place is all of the human brain's unknowns. It would be almost contradictory to imply that an entity created in the name of the human unknown could ever be conceived of by what a human knows. Indeed, if humans could prove God's existence, there would be no need for a God anyway, because in essence we would be Gods ourselves.
So very much in my own opinion, Kierkegaard is right in his assertion - it is impossible to use rational thought to prove the existence of God, because God is the one thing beyond the reach of logic. For this same reason I have no fear of the threat of absolute artificial intelligence - humans simply cannot create themselves. In my own beliefs I call myself an Agnostic. The reasoning behind this is that in my opinion it would be stupid to say there is no possible way a higher power exists, certainly in light of all I see around me every day. Yet, at the same time, to presume I could ever conceive of it-which-created-me, or even exactly what it wants from humanity would be foolish (to put it nicely). Instead, I live according to my own codes of ethic which I must assume that if there is a God, it gave me to use as a guide. I would never push this code of ethics upon anyone else, nor would I argue that anyone else was wrong for having their own views on God. To define God for someone else is like telling a fish to breath oxygen, unfair and unlikely to work - all and all irrational in itself.
Now, ration does not take into consideration good and evil. Good and evil are sweeping definitions for intangible thoughts and feelings which compel us against logic. If one realizes they cannot prove God exists through any action of the human brain, one must also realize that the guidelines for what makes something good or evil have been somewhat arbitrarily thrown together over the centuries by man himself. If it IS man who defined right and wrong, then like anything man creates, it has no basis in reality so much as human trial and error, pleasure, want, pain, and, all sweeping, emotion. Something created by man, if we consider there to be a God, is so far down the totem pole as to make a very poor proof in argument. This aside, I would in a way hate to see the entire would following my exact view of the conceivability of God. Religious belief is grounded completely in faith, a good thing, since we do not know for sure what's going on in that area. Most have faith which finds at least a small basis in what are perceived as truths told to them by other individuals. If everyone felt no human could conceive of God, there would be no additional credit given to religious scholars' statements on the subject, as it would be known that there was no real way for them to know. If it was widely believed that we could never as mortals conceive of God, the number of people who have faith would drop sharply, and thus the morality of the human population as a whole would go down quite a bit. For many, it is only the idea of a much more powerful force watching them at all times which prevents them from living however they please, a trend that would be doomed to end up bad for all involved.