it does not exist. there is no such thing.
and any case for it, one way or another, can only be attributed to, motivated by, and stink of agendas related to ideology to which the person making the case subscribes. Marxists say humans are good for one set of reasons, and christians say humans are evil for another set of reasons -- but both only seek to further their cause with these fictional claims.
while i truly believe, without a single doubt in my mind, that humans are not inherently anything -- that we are adaptable to any condition, malleable under all circumstance, and each one of us are capable of behaving in a million ways, from saintly compassion to horrifying cruelty. if any one of us is groomed and educated and trained, we can become a spiritual leader, and if we are mal treated and abused enough, can become a serial killer.
a misguided soul remarked once that humans are inherently selfish, because if there was one piece of bread left and 4 people are starving, they would all want it for themselves. well i'm certainly impressed because a leap across the gap in logic of this proportion truly requires extraordinary levels of stupidity. if people are put in desperate situations, they will behave desperately. sure, and if these same 4 people had all taken ecstasy 2 hours before they would be laughing and hugging eachother -- what is the point? circular logic like this is for the birds.
of course a certainly level of "free willie" and "personal choice" exists, but its importance compared to the shaping circumstances in which people find themselves have ALWAYS BEEN GROSSLY EXAGGERATED. "nature" is privileged in our art and thinking over "nurture" for several reasons: 1. it is easy: "this person is good, this person is bad" -- like in the movies. 2. it appeals to the romantic notion of fundamental individual differences and uniqueness 3. it allows the comfortable and well to do to feel self righteous: "i've never committed a crime because i'm good, and not because i come from a perfect family and i've never needed to" 4. it upholds the illusion of personal "freedom" - and we prefer to think of our lives as autonomous and our choices our own, and not dictated by circumstance. but reality, when examined by a sober and rational mind, seems obvious: that environment dictate much much more the shape of our lives than we like to admit.
and there is a 5th reason: that the structure of much of our bullshit society of lies will crumble if people stop thinking like this ---- just think of the "justice system" ---- which i'd like to point out once and for all, is not "flawed" as much as it is fundamentally absurd and cruel.
of course there are countless exceptions but if you grow up poor and neglected from a broken family in a squalid part of town, the chances of you becoming a criminal is exponentially greater than if you were born in the royal family. i don't see how anyone with half a brain not permanently damaged by doctrine can argue with this.