An atheist on CARM posted the following as the OP of a thread:
Many Christians have argued that there are objective moral values. Yet it seems as if all humans get their morals from reality and that morals vary from culture to culture and sometimes from person to person within a culture. If there are objective moral values, how would we know it? And what purpose would it serve if we all have morals based on reality?
I posted this in response:
Hi, I’m an atheist and I am near the end of a BA in philosophy.
I think it is mistaken, on both rational and polemical grounds, for atheists to argue against the existence of objective morality.
All living things face the alternative of life or death, and every living thing has a means of survival to keep them alive in the face of this alternative. Plants have their automatic chemical functions, and the lower animals have instincts. Human beings, however, use reason as their means of survival, which means that they have to exert effort and think about the way they live, not depend on their automatic functions. It is necessary for a human being to define a set of moral principles to live by, and the only rational standard for a moral code is life.
Most people sense that morality has a life preserving function. As a result, they react strongly to the idea that morality is merely subjective, and see this idea as destructive, although they may lack the conceptual tools to articulate this properly. If people have to choose between religion and moral subjectivism, then they will choose religion, as the fundamentalists on this forum illustrate daily.
The only hope for atheists is to articulate a set of secular values that are based on life and disseminate these values into the culture. Such a set of values has been defined by Ayn Rand, and she has provided the means for disseminating them by presenting them in the form of art, i.e., her novels.
You can find elaboration on the argument I made in the above post here.