I tend to think, that just as we see in the second law of thermodynamics entropy (disorder) will increase over time, yet we also see that ordered systems self-organize out of chaos (the galaxies, stars, planets, animals, plants, DNA etc.)
I read that the self-organizing orderly systems do not violate the Second Law of Thermodynamics because the seeming decrease in disorder of the localize system arises at the expense of increasing disorder of the general system. If we are subject to this immutable law without any other recourse, then continual wars strife, and conflict are a certainty of our impersonal universe; any attempt to counter such natural impulse would be futile.
If morality is instinct, then the term "morality" need to be jettisoned, as it obfuscates discussion. Instinct serves to propagate the DNA of the creature, then the tribe, in that priority. A tendency or sentiment that fosters species level propagation at the expense of the creature's or tribe's DNA propagation is not instinctual, and thus, "immoral" (if there can be such term). From the logical framework you have provided, the instinctual imperative is to place the self and his tribe above all else.
Man's fate would be no different, whether he is from a world 2000 years past or current, since his perceptual matrix would be instinctually driven. In fact, wouldn't the set of instinctual imperatives be more aligned with man 2000 years past, than the modern man, who clouded by technological smog to imagine himself above the immutable instinct of his DNA?
We seem to be in a loop. You want to prove morals come from heaven and hell; I argue morals need not come from any absolute external authority and can self organize through the action of intellectual self preservation instinct of humanity.
No one has ever changed their beliefs because he read some pithy "proof" on a web post. I am trying to understand your logic better. You are proposing that the self-preservation instinct allows for a social matrix of universal empathy towards the weaker and the inferior. My observations and application of your assumptions do not lead to such society.
Observe any living group in action: lions will kill other lions not belonging to their pride, oak trees will kill off any seedling that is invades its territory, omegas and gammas in a wolf pack do not reproduce, male bears will kill any bear cubs that wander into its view, etc. If your conclusion is that the tribal separation and intraspecies wars are our given fate, then I absolutely concur with that conclusion. If you are advocating the liquidation of the infirm, sick, and the genetically inferior, then based on your premise, I concur with that conclusion.
From your premise, I cannot deductively arrive at some hippy free-love for all society based solely on survival instinct, no matter how intelligent the animal may be.