The human spark is the ability to move beyond this to some degree and seek out what is good for others even at a cost to yourself.
No Joel, lots of animals do that. Many animals put more effort into reproducing or defending their kin than on their own pleasure. Their instinct is primarily to reproduce.
Humans, on the other hand, are the only species who choose whether and when to reproduce. Most of us do this for selfish reasons, we want more money, more time, more sex, whatever, putting the very survival of our bloodline at risk for temporary selfish pleasure.
I would go as far as to say that it is our selfishness more than our selflessness that defines us as humans.
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Those who can induce you to believe absurdities can induce you to commit attrocities - Voltaire