I think people are inherently human, they have the potential for great good, AND great evil. This raises the age old nature vs nurture argument, and for me, the answer to that is A GOOD MIX OF THE TWO.
We make choices every day. I strive to make good choices, and I am striving to raise children who will make good choices. However I'm sure I've made some rotten choices somewhere along the way. Nothing evil as such, but the point is that, as a human, both are possible.
I may just get slammed for this answer, but you asked it...and I will give MY Opinion.
In all my years of study on this Very Topic.....I found an answer.
I have over the years found young children when playing with other young children say age 2 and up, doing something quite strange.
If they were not happy, and wanted something another child had, they would take it...with may I say a fair amount of force.
If said child did not get what it wanted, as tiny and sweet as they are, that child would hit the other child.
No parent would have taught the child to do such a thing, and the child would not really be able to retain any kind of info for 'how to get what they wanted'.
The action comes from 'instinct'.
It has happened for a long long time.
Evil is too strong a word when talking about early childhood actions, and that's where we need to look when viewing, are people inherently good or bad.
The view I share, and a great deal of my colleagues is we are born with a mean streak.Some will say (Bad).
How that person deals with it, as they get older is up to them.
For the last 14 years I have worked with men inside maximum security jails.
I have asked psychologists who have had to deal with very high profile killers....'Why'? do they do what they do.
It comes back to the human being being born 'short' of perfection.
It also comes down to a need to want power over others.
Hence why we see the most dreadful actions on other people who were going about their daily life, and never saw it coming.
DEFINE EVIL, I would rather say there are only 2 types of people in this world -GIVERS or TAKERS and then look upon them as bigger or little takers in what ever category they fit. For example Big TAKERS or Little TAKERS.