In game theory, games have global optima and Nash equilibria, and they don't always coincide. Selfless people seek global maximum, selfish people seek Nash equilibrum (maximizing their gain given the others also maximize their gain).
As a society, we have choice to change the rules so that global maximum coincides with Nash equilibrium.
When a person causes negativity/unhappiness, the person(s) on the receiving end gets an equal positive amount of karma. Karma is what determines our long-term happiness or lack thereof.
When a person does something intended to cause positivity/happiness, there is no negative effect on the receiver, even if they refuse the gesture.
In other words, acts of selfish negativity incur a zero-sum negative karmic effect, every time, without fail, though often without being observed at the time (or even, ever). OTOH, acts of selfless positivity only incur positive internal karmic effect for the doer; nothing is lost by the receiver.
In yet more other words, we can only receive negative karma from our own actions; others' actions can only result in positive karma for ourselves (if we are on the receiving end of selfishly negativity). For example, a poor person loses no karma from accepting charity, though the giver definitely gains.
As such, karma is skewed asymmetrically towards easier positive creation; i.e. it's only a zero-sum game when the first choice is negative/selfish.
Why, then, have the world's populations not yet created a "Heaven on Earth"? Because we human beings are also free to ignore all notions of karma and the associated question of why we are happy/unhappy. If a person chooses to believe that they are just amoral animals competing for scarce resources, then they are fully authorized to live their lives that way. We are also free to believe that the Earth is flat. The universe is the sole arbiter of the truth, however, and we all reap what we sow. Every time, without fail, with perfect justice, however difficult it is for us to comprehend at any given time, given our state of moral undevelopment.
Clearly no one had any ‘karma’ 3 billion years ago, since living organisms did not exist.
From another perspective, I'd say that the first human being could sin against God, but that doesn't align with my understanding of how human beings were created. My understanding is that Adam was created in a state of grace, as a Prophet, free of negativity, but that as the population grew, our negative tendencies (to vice) established itself and the karma began to flow.
[I have some understanding of how the universe works, but I in no way claim to be authoritative. That said, I don't see any obvious errors in my reasoning.]
How could they have karma if they predated the first human being?
If karma is the result of will, what we're asking here is "When did the first willful creature come into existence?"
(Or, if karma is simply synonymous with cause and effect, then we can probably say the first karmic act was the big bang, the effects of which we are living with even now. But I think that's a less useful view, so let's abandon it.)
> Karma is a human-only dimension of the universe we inhabit. We alone have free will
Some say only homo sapiens is willful, but that seems unlikely given what we've learned about other now-extinct members of our genus. Did they have free will and/or karma? Do elephants, great apes, dolphins, house pets truly have no free will?
At this point it becomes imperative that we define "free will,"[0] and we just might get stuck there. It's a toughie. We are apparently physical systems, constrained by the laws of the universe just as every other system. Perhaps we are simply acting out our biological programming, another domino falling in a long deterministic line back to the universe's beginning[1]; perhaps we are endowed with the ability to modify reality itself through observation, that our "will" acts in concert with physical law to create reality; perhaps all things have a measure of "will" proportional to their internal systems' complexity[2]... maybe some version of all of these[3] or none of them.
In my opinion, karma is a useful framework for recognizing that we are, indeed, all connected to Kevin Bacon, and whatever we do will ultimately effect that poor man.
[0] https://en.wikipedia.org/wiki/Free_will [1] https://en.wikipedia.org/wiki/Determinism [2] https://en.wikipedia.org/wiki/Panpsychism [3] https://en.wikipedia.org/wiki/Compatibilism
A newborn can have a chronic disease that makes their life terribly difficult. Do you think negative karma caused that? Or can other things cause unhappiness?
Some people have been given greater challenges than others. Any difficulty given by the universe itself only counts positively for us, but we have to use it properly; i.e. we can't let it give us an excuse to be an ahole.
On the other end of the spectrum, most people feel that being born into wealth would be a great blessing, but look how those fools behave, wasting their blessings on themselves for meaningless pleasures that deplete the Earth, being callous in their treatment of those less fortunate, and generally working with their fellows to keep themselves on the top of the heap.
Being striken with disease is an effective way to go within oneself and connect with the Source of all creation, which is an essential part of the intent of the creation of our human nature. One way to look at the Unfathomable Creator is as the Ultimate Loner. It is a blessing to have been created as a human being, for only we can connect with It, and receive the blessing of reaching out for It.
That is the Ultimate Design of the human race, with our absolutely free will, but within a universe that rewards the seeker who connects with the sublime majesty of the Creator of all that will ever be. The Greatest Command is to, first, "Love God with all your being". That is not because we can add anything to It, nor because It is needy in any way. No. It is because the universe is designed to reward those of us who use our free will and energy to radiate love into the universe; it radiates that love back from within ourselves in happiness, clarity, and purpose.
Another way to look at the underprivileged (in money or health) is that they are rewarded for being where a person of means can prove their humanity, and thus giving them the chance to learn how happiness is gained from selflessly sharing, not from selfishly keeping.