All living things prosper when things go well for their DNA’s historical programing and poorly when their environment deviates very much from that programing. We humans currently are doing very well here near Earth’s surface where we can control our personal environment to mid 70° temperatures, with expected air, water, food and the other things we like. But, in the bottom of the deepest diamond mines of Africa, the deepest places humans have ever ventured, when the rocks are lifted to uncover pristine new material, there are living things. Not anything we would readily recognize, these extremophile microbes don’t process the same kinds of energy we do, but they do consume energy, survive and reproduce. They are alive.
These two forms of DNA, extremophile and human, are doing just fine in the environments in which their ancestors lived, but neither would compete very well with other creatures in situations much different to those in which they live. Humans don’t do well in those diamond mines without all sorts of protections, but probably those things living there would fail quickly too if exposed on the surface, where we get along just fine.
When we think of rewards and punishments in the abstract and apply those concepts to these two very divergent species, it seems reasonable to focus on what helps or hinders the individual and its species in interacting comfortably within its environment and reproducing. As the “philosopher” Jesus said his goal was, “To help people live and live more abundantly.” That idea seems applicable to all living things, not just humans.
What happens to the individual of each species when it dies? The microbe can be seen to quickly be dissolved into its constituent components. The problem of personal survival, especially conscious survival, arises for humans when language developed sufficiently, some 50,000 to 100,000 years ago, for the people to become aware of their personal death. Language is necessary for this. Just seeing yourself in a mirror permits only a realizing of your personal independent being, and some other animals are capable of this. But, as a primitive human, without language, you could perceive an oncoming personal injury in a mirror, when seeing a reflection of a tiger creeping up behind you, and you would take appropriate evasive measures, but you couldn’t perceive your own death. It requires the advent of language and the transmission of culture before people can become aware of their own death. It is then that the question of what happens to one’s personal consciousness after death percolates up. We can see and are forced to accept the deaths of others like ourselves, and when we realize we are essentially like them we must face our own probable mortality.
It is difficult to accept the vanishing of all we hold dear into an absolute nothingness, and so we fall easy prey to optimistic ideas such as Heaven. The fantasy aspect is easy to accept because we have no experience of afterlife, and therefore we and others can make up absolutely anything. We are on safe ground with our future projections because they are not really in the future of real time; they are untestable and thus unchallengeable speculations. The thought of Heaven gives us comfort, and the feeling that what we value has an eternal meaning and thus our struggles in this life have a purpose. Then to add more manipulative power over us, our authority figures postulate a hell in which we will be forced to live for eternity if we disobey them. That hell is also untestable and thus also unchallengeable, but it can be postulated in myth, song, picture and ritual to be made most hideous. The thought of being treated this way is punishment enough to keep believers in line with the moral teachings of their elders.
Threat of hell is punishment in itself and generates acceptance of authorities’ teaching.