When talking about morality, the atheist has three options to revert to, all of which are equally problematic. They can believe that morality does not exist, morality does exist, but only as a subjective thing, or that morality is objective.
The first two suffer from the safe issue. If morality does not exist, then everything is permitted. This should not be considered a serious position. It is impossible to consider that acts like murder, rape, and genocide are in no way wrong, when we consider how many people suffer from these on a daily basis. Emotional outrage and things being wrong are not equivalent, if morality does not exist; emotional outrage is no reason to change anything. Indeed, there is perhaps not even a reason to be emotionally outraged.
The idea that morality is totally subjective falls into a similar pitfall. If this is the case, morality is downgraded to something pointless. In some cultures, it would follow that again, rape is morally acceptable. It also means that anyone can make equally powerful claims about morality, including the mentally challenged, irrational, and psychopathic. This doesn’t really make any sense. People tend to cite this view of morality as different from the first, in the sense that it promotes “discourse’ and “rational discussion” about morality. It is unclear how. If nobody can be right, then conversations can never get anywhere. This is also a poor view of morality; it is nihilistic and pessimistic.
The third idea, that morality is objective without a god, requires some kind of external grounding, but it’s not clear where this could come from. It could not make any prescriptive claim about society, and even if we accept the view that happiness is the greatest good, there is no reason why we should strive towards it. This is the question the atheist can never answer – moving from an is to an ought. Thus no matter how well they could ground this objective morality, they cannot explain a reason to follow it.
The theist can explain a reason why – God. God, in his infinite goodness and wisdom, can guide us towards morality and a better universe. It is important that we do not confuse the idea of “God” with a kind of “superhuman” figure. He is not simply a much better person, but incomprehensibly so. By being the creator and guider of the universe, he can create and guide its morality. This explains not only the is but the ought.