Atheism deals only with lack of belief in gods. Raelians, for example, are atheists and that does not preclude them from believing in all sorts of weird, evidence lacking ideas.
That being said, atheists tend to value beliefs if they can be properly justified. If the reason for atheism is the lack of evidence in favor of gods, why would a self described atheist believe in karma or in reincarnation when there is no evidence in favor of those?
Again, an atheist can believe in karma with no problem but if you ask me I would say that such a person is just being inconsistent. In regards to atheists not believing in anything I just think such a statement is hilarious. As an atheist I believe in tons of things, namely ones that have evidence of being real going for them. Why would it be any different? It is as easy as that.
If there is not a definite definition of Karma, why bother with it?
I disagree with the statement that there are “no defining definitions of morality”. Nor do I agree that everything is “subjective”. Fact is that what we call morality is nothing more than of society developed concepts that can and are enforced (that is why we have laws). Compare this to karma where it does not fit nor is necessary in societal discourse. Of course it would be interesting to hear a non-spiritual definition of karma. I guess it would sound like a non-supernatural definition of god. It would make the words god and karma devoid of any useful meaning.
BTW, Sam Harris has addressed the subject of morality briefly here (see point 3).
In summary, there are many things one can not disprove. So? Does that mean they are all worthy of our attention? Not being able to disprove “something” means nothing if that “something” has not been proven in the first place. It is the typical putting of the apple cart before the horse.
Like fairies, ghosts, or gods, mystical concepts feed on our fascination with the mysterious and how we try to make sense of it. That is why the non-existent, be it supernatural beings or mystical concepts, are so appealing. It is just a way of blunting fear and despair, of having the feeling that eventually all wrongs will be right. That there is hidden meaning in coincidence and that there is a purpose for everything.
Personally, until such things are proven, I can do nothing else but hold my belief. I think it is the moral thing to do.
Here are 2 additional cents:
It is true that the idea of Karma can be conceived without the need of a god. That is why I did not use the words god or cosmic power in my previous post on the matter.
I don’t think there are “bad atheists” (maybe, like Raelians, irrational atheists but that is another story). Nor do I believe that judgment has anything to do with it. It is all about what the evidence and the facts can support and the idea of Karma is not one of those.
Still if anyone wants to use the word Karma in a colloquial non-meaningful way (since we know that people do not always get theirs), be my guest. My only question would be, why? At least when we say good bye we actually mean something.
Karma is defined in many different ways depending on the religion/philosophy.
I have not seen any evidence in favor of Karma when it is defined as “eventually getting what you deserve”. I know of really bad people, through out history, that died without Karma ever catching up to them.