I've posted in this thread a lot without really addressing the question, so, here's my take on these things (and I am far friendlier towards science than I am towards philosophy). Foremost, "good" and "evil" are ridiculously simplistic terms when talking about people. Ideas and actions may be good or evil, people may do good or evil things, but people themselves are too complex to be described thusly.
I suppose there are three things that determine a person's character: nature, nurture, and situation. No one has any evidence as to what percentage of our characters are determined by nature as opposed to nurture, but I think most people who study human behavior in any capacity (psychological, neurological, etc) would concede that both play important parts. And frankly, that's all pretty obvious to me. No one is born a tabla rasa, nor are we born with a determined character, rather, our environment interacts with our predispositions, our experiences inform our innate traits and vice versa. The third aspect, situation, I suppose plays a greater role for some individuals than for others, but I think most people, when faced with certain situations, might find they are able to act in ways they never considered part of their characters -- this may be good or bad: Some people perform feats of great heroism and bravery when faced with trying circumstances, performing acts of immense good when even they wouldn't have expected themselves to be so capable. Likewise, some normal people (more, it seems, than is comfortable) can do acts of great evil when coerced, the Milgram Experiment (not to mention the Nazi atrocities of WWII) are prime examples.
I suppose there are three things that determine a person's character: nature, nurture, and situation. No one has any evidence as to what percentage of our characters are determined by nature as opposed to nurture, but I think most people who study human behavior in any capacity (psychological, neurological, etc) would concede that both play important parts. And frankly, that's all pretty obvious to me. No one is born a tabla rasa, nor are we born with a determined character, rather, our environment interacts with our predispositions, our experiences inform our innate traits and vice versa. The third aspect, situation, I suppose plays a greater role for some individuals than for others, but I think most people, when faced with certain situations, might find they are able to act in ways they never considered part of their characters -- this may be good or bad: Some people perform feats of great heroism and bravery when faced with trying circumstances, performing acts of immense good when even they wouldn't have expected themselves to be so capable. Likewise, some normal people (more, it seems, than is comfortable) can do acts of great evil when coerced, the Milgram Experiment (not to mention the Nazi atrocities of WWII) are prime examples.