The best minds of all the centuries have been trying to answer them. The efforts of even the most veteran role player are not going to significantly impact the Halls of Academia. Still, any decent game creator must have some sort of answer to these questions. The grey approach is both more realistic, and presents the players with more interesting choices. I'm going to develop some other traits of mankind.
Man is a creature of instincts.
Man is also capable of rationalizing his actions, so that however black his actions may appear on the surface, many individuals can portray themselves as white in the minds. Finally, after reviewing these other dimensions of human behavior, we can return to the original criteria of Good and Evil to see what is left, if anything.