Tomorrow, for example, I could choose to devote my life to the health and well-being of all other humans or, perhaps, only those most in need. Once I die, however, whatever good I experienced (and whatever hardships I endured because of my virtuous behaviour) dies with me. The people I helped will also one day die, and whatever good or hardship they experienced will die with them too.
Alternatively, I could choose to devote my life to harming all other humans or, perhaps, only those most deserving of such treatment. Once I die, however, whatever hardship I experienced (and whatever good I might have experienced thanks to my vicious behaviour) dies with me. The people I harmed will also one day die, and whatever good or hardship they experienced will die with them too.
Good and evil, hardship and suffering, virtue and vice, they are experienced and do not exist or perpetuate beyond those who experience it. We, of course, create conditions that will have an effect on future generations, but, even so, those effects will die with those generations too.
Effectively, on a long enough timeline, all our actions — moral or immoral — are inconsequential because they and their effects cease to be experienced. The total amount of happiness or suffering generated is inconsequential. The total amount of virtue or vice inculcated is inconsequential. The number of times people acted or did not act in accordance with a universal moral law is inconsequential. Even coming to understand or not understand the full meaning of death is inconsequential. It’s an experience like any other. It also won’t survive death.
Our genetic material, of course, will likely survive much longer than the effects of our actions. Nevertheless, even if we become self-consciously Darwinian, acting only in those ways that maximize the safe transmission of our genetic material, it does not seem likely that the species or its ancestors will survive forever. It’s theoretically possible, but it is too thin and tenuous a possibility upon which to build anything like a rational morality.
I am, nevertheless, not terribly concerned by my revelation. I am moral or immoral because of an unknowable causal history over which I have exercised almost no control. Understanding that there is no rational justification for moral or immoral behaviour — really, any behaviour at all — seems unlikely to affect how I behave. At most, it may affect how I assess my behaviour and the behaviour of others. For me, it seems a bit silly to feel high and mighty about choices that weren’t made by me but, instead, have happened to me. Of course, that assessment is probably but one more happening that has arisen from the loose anarchical confederacy of environmental interactions for which my conscious mind takes credit.
I am reminded of a story I read in Zen Speaks. A doctor faces an existential crisis because he can’t see the point of practicing medicine when he inconsequentially saves the lives of soldiers who go on to die in battle. Whether in war or peace, death is the final end of all medicine. A doctor, at best, delays the inevitable, so why bother? The doctor returns to his battlefield medicine when he realizes that he practices medicine precisely because he is a doctor.
The universe is neither rational nor irrational, even if we humans have developed a rationality with which to make sense of it. Likewise, morality is neither rational nor irrational, even if moral behaviour has helped us to evolve into creatures capable of rationality. Rationality, I think, requires us to accept that there may be no rational justification for some of our most fundamental behaviour.
So, why be moral? Because you are.