By Katherine Traylor
The human species requires a combination of altruism and selfishness to survive. You've got to be selfish enough to prioritize keeping yourself alive, but you need to be selfLESS enough to want others around you to survive, too. (This is true of all species, as far as I'm aware, but I'm not a biologist, so for purposes of this discussion I'll stick to humans.) Humans are an extremely social species, relying heavily on each other for day-to-day survival, so the human species needs its average member to be much more altruistic than (say) a salmon. You might not be rushing into a burning building to save a stranger's baby, but you're probably going to yell for help if you see a neighbor's house ablaze.
At least, most people will.
Every person alive lies somewhere on the moral/emotional spectrum between "completely altruistic" and "completely selfish."
(I am not a psychologist, a psychiatrist, a philosopher, or a sociologist, so I don't have the correct terminology to use here. "Narcissist" and "sociopath" come to mind to describe a person who's completely selfish. I don't know any psychological terms for a person who's completely altruistic (though in colloquial terms, both "saint" and "doormat" come to mind). I don't want to muddy the waters with incorrect terminology, so I won't try to be technical. For the sake of simplicity, I will use "good" in many places to refer to a completely altruistic person, and "evil" to refer to a completely selfish person. You can take those words to mean "socially constructive" and "socially destructive" if you'd like.)
Each person will act, with the abilities and willpower that they have, in accordance with their moral/emotional alignment. Completely selfish people will act only to benefit themselves. Completely altruistic people will act only to benefit others. Most people are somewhere in between.
*The "abilities and willpower" part is very important here. A very talented person, or a person with lots of social/political/financial resources, will be able to accomplish much more than a person with limited resources and abilities. A person in good health, with strong executive function and good organiational skills and lots of time on their hands, can get much more done than a person who is disabled, exhausted, disorganized, extremely busy, etc. etc. So a "powerful" good person can easily counteract the efforts of a "powerless" evil person, and vice versa.
UNFORTUNATELY: