With young kids, it's been interesting to see how they have begun to develop a morality -- a feeling of what ought to be done and what ought not to be done.
Morality is a large reason why many people have found theism to be the only rational worldview. Arguments for the existence of God, and so forth, are commonly rooted in morality.
The only game in town for human morality origins from a naturalistic worldview is a bit strange -- assuming a naturalist accepts Darwinian evolution. Assuming they do, morality can only be understood as not an evolutionary-created mirage, as some think, but as an evolutionary suicide pill. Evolution, as correctly understood, "cares" about surviving long enough to have kids who are then fit to have their own kids, etc. To think of it was being concerned with the survival of a species, is not the same thing, or really even close. Morality, on a personal level, is actually anti-evolution.
Animals, on the other hand, just act. They are not in any way concerned with what they ought to do. They simply follow their biological impulses to survive. Surviving in herds is not game theory.
Of course, morality is often studied in higher animals. Seeing animals punished for "selfish" behavior, is not a rare observation. However, and this is a big however, morality is prescription -- how it can be studied by description is not an insignificant question and certainly not settled law. Simply stated, we are not describing physical interactions or chemical structures. Furthermore, and this is no small furthermore, we can describe what an animal or animals do in certain situations, but, that is not the same as what the animal thinks it "ought" to do? This is morality, it is not the act by irrational beings.
But, all that being said, there is one concern that would really keep my up at night, if i had a naturalistic view. For the sake of argument, assume morality rushed on the scene say during the (also) mysterious emergence of human conscience. So then, why in the world would we need discreet moral laws to redundantly tell us what our natural impulses should? Well, it does not take us long to realize that most people, if they can get away with it, will bypass what their morality will urge them if they can a) stomach it and b) understand it will give them some benefit. So, therefore, we need the laws of Moses or some other morally similar set of precepts to tell us what we ought to do, because our natural instincts tell us something quite different. Again, morality on a personal level, appears to be anti-evolution.
And, if I was a naturalist, even more daunting for me: Yes, this includes an appeal to emotion, but, we are emotional beings, so this should not seem to unusual. Thoughtful naturalistic atheists and theists alike accept without subjective morality, there is no grounds to say anything is truly good or evil; murder and doing worse is no more good or evil than picking a flower. But, if evolution is truly solely steering the morality game in whatever way, one can very much make the argument that, since evolutionary fitness is the only goal, not doing everything you can to increase your evolutionary fitness is the real evil. Not murdering and doing worse would be evil from nature's perspective if we were hindering our evolutionary fitness. Selfless lives of service to others, that for some reason many of us admire above all, would be the most evil. To be clear, though, just because this sound absurd does not make it not true. However, what for me makes this seem extremely unlikely to be true is that, it appears to provide a clear defeater to the naturalistic viewpoint (if one is to believe evolution to be true, of course. If a naturalist, does not, then they have no defeater. Just a ton of other problems).
This reminds me of the well documented reduction in number of children that atheists have compared to theists, which, means belief in God is consistent with reproductive fitness. In the same vein, but in a twisted way, morality has strong anti-evolution effects: If all people lived in the highest state of morality, selfless love, they would, as Jesus put it, lay their lives down for strangers. Want to get yourself out of the gene pool in a hurry? Go ahead and do that. But many make the simple argument that it helps our species survive when we have people performing moral acts. That is all fine and dandy, but even if you believe that, it has nothing to do with Darwinian evolution. The undeniable fact that morality pushes back against many of our biological impulses that have allowed our animal ancestors to survive, and, obviously us as well, flies directly in the face of evolution. And for me, even if you can convince yourself that Stalin did no evil and folks that have died for human rights for others three continents away were not heroes but evolutionary mistakes, the fact that morality pushes back on against nearly all our evolutionary instincts is yet another daunting obstacle to retain the naturalistic worldview.
