Is There Such a Thing as Evil?

Does evil exist as a thing in itself?

Is Darkness a thing or is it just the absence of Light?

From my experience individuals do not decide to do acts because they are evil.  They decide upon a behavior that serves themselves in a particular situation.  These behavior can certainly be judged as evil by an observer.  However, the individual chooses the act with a mindset of something beneficial to him or her many times without regards to its consequences to others.  A rapist sees rape as a satisfactory means to an end possibly a violent eruption of his libido that results in some type of release which he finds pleasurable.  The victim sees this as evil whereas the rapist sees it as some type of perverted pleasure.  This reflects his lack of concern about another person but the act itself is considered of some positive benefit to him or else he would not act.  The point is the rapist decided upon an act that he judges as "good" for him even though it is at the expense of another human.    BTW, I am in no way excusing rape, I am simply explaining a thought.

I would suggest no individual ever does an act because he or she sees it as evil.  These individuals may know the act is evil but they are doing it for a greater good, their good.  There are times when killing another human is considered a good thing such as someone resisting a rapist by shooting him.   This would be a personal judgment that this act will be beneficial to them thus an act worth doing even at the expense of another person.

The point I am attempting to make is that evil does not exist in itself.  A person may complete an evil act but their intent is always for what they judge as good for them.  They may be delusional or psychotic but this does not change the nature of their intent.

My Christian friends tell me that Satan is the embodiment of  evil.  However, if evil does not exist as thing in itself then how can Satan exist?  How could an entity exist if his construct is compose of a lack of something? You can not construct anything using darkness, the lack of light.  I would conclude this is true of evil since evil is the lack of good rather than a thing in itself.