I don't see how a Christian, and many other religious folk, could agree with you. Atheists reject God and isn't that the most immoral act possible in their view?
I think you must have meant "cannot perform acts which we consider moral."
Rather, it is that they can give no rationally coherent and consistent account of their morality by atheist lights.
I consider myself agnostic, but I'm sure you'd make the same claim about me. However I have a very simple account of morality - people are better off with morality than without. Neither civilization nor society, even tribal ones, would be possible without it. It is the same with many other social institutions, government, markets and the like. Accounting for my own morality is similarly simple, I have been inculcated with it from birth.
But that isn't the whole story. I think there is a real, objective human nature, behavioral traits shared by all, some few abnormal people excepted. Hierarchical social structures is an example. Morality builds upon, or tends to respect, these shared values.
If you are an agnostic then what do you mean by "morality" other than what YOU think people are better off with than without? And what standard would make your morality better than another agnostic's totally different conception of morality? In terms of civilization, the most successful civilization the world, Rome, was completely immoral from a contemporary point of view. People butchered and fed alive to animals for entertainment and sport. Armies pillaged cities and killed every inhabitant or sold them into slavery. The army routinely killed or whipped their own soldiers to maintain disipline. The Romans considered this completely "moral" and their civilization lasted almost a thousand years.
However I have a very simple account of morality - people are better off with morality than without. Neither civilization nor society, even tribal ones, would be possible without it. It is the same with many other social institutions, government, markets and the like. Accounting for my own morality is similarly simple, I have been inculcated with it from birth.
Is there an obligation for civilization and society to survive? If so where does it come from? As far as having been inculcated with moral principles from birth, is it just a matter of psychological conditioning, and if it is, then is morality something than can be changed at will, with the right scientific means?
I think there is a real, objective human nature, behavioral traits shared by all, some few abnormal people excepted. Hierarchical social structures is an example. Morality builds upon, or tends to respect, these shared values.
I don't see how a blind, impersonal Darwinian process produces a fixed human nature. And if by abnormal you mean something like dysfunctional, then it doesn't seem to make sense to assign that term to anything produced by a purely physical process that has no goal or purpose. Abnormal compared to what? It makes sense to say that my lawnmower is not functioning as it ought to when it doesn't start, because it was designed with a purpose. But how does an impersonal evolutionary process produce something 'wrong' with itself? How In such a universe is there is any objective basis for assigning a value of "better off" to anything?
Cordially,