Arthenor wrote the following comment elsewhere on the site:

I am not arguing that atheists can not have morals (that is, moral values, moral systems, or moral ideas that attempt to follow). What I am arguing is that atheists, naturalists, or materialists lack any rational basis for such moral ideas.

This is rather interesting, as he seems to be suggesting that atheists are moral people somehow despite lacking any rational reason to be moral. That is to say, atheists are moral by some happy accident despite their irrationalism. So either we somehow in our irrationalism accidentally behave morally (most of the time) or there really is some rational or basis for our moral ideas. It is hard to see how anyone could honestly hold the former idea. Surely if atheists, naturalists, and materialists have morals then that is no happy accident.

He goes on:

I am certainly open to considering any reasonable counter-examples you would like to present, but so far I have seen nothing more than mere assertion and unjustified, vague claims regarding reason and consensus.

He dismisses “vague claims regarding reason and consensus” but that is itself a process of rationalization. You can also factor in biology and our evolutionary history as a social animal. Once you do that, then you should more or less realize that morality is a social processes arising out of the particulars of our social relations. The isolated individual does not need morals, but once you begin living in groups some kind of morality needs to be codified. 

There could conceivably exist a society of murderers and thieves – so long as they agree not to murder or thieve each other. Morality is not mysterious. It is not supernatural. It is a part of our being as dictated by evolution, our efforts to live with one another, and certainly our reason. This should be as plain as daylight. So why isn’t it?