As some of you may have read, I consider myself to be both a Marxist and an Existentialist. It can go without saying, then, that I am largely interested in Atheistic existentialism, but so far I am leaning towards Kierkegaard because of his writings on existential despair, which I thoroughly enjoy. (I can't help but compare the 'despair of necessity' to Marx's theory of commodity fetishism and alienation.) But it seems that there was an intense battle between 'orthodox' Dialectical Materialists and existentialism. But honestly, I don't see why. Lucaks and Novak are the two Marxists who leveled the main criticism against existentialism. I respect both of these men's works (I am particularly fond of Lucaks' explanation of Leninism) but the main argument that both level against existentialism is that it is an "anti-scientific" view. I don't think this is necessarily true. I adhere to the theory of dialectical materialism and historical materialism, but I don't think that it is particulrly deterministic or taken as an objective truth (maybe an interpretation of objective reality) The supposed contradiction between existentialism and dialectical materialism seems to me to be just as plausible as the idea that existentialism is in contradiction with the theory of gravity. So, I don't think the argument that existentialism is "anti-scientific" is true or holds ony water.

But then, I don't agree with the argument that existentialists throw at Marxism. They seems to think that Dialectical and Historical Materialism is a hard-determinist philosophy. Every Marxist philosopher that I have come across has rejected this notion. Engels said on the subject of freedom of the will:

"Freedom is the appreciation of necessity. Necessity is blind so far as it is not understood." -Engels in anti-Duhring

And Lenin says something to a certain extent in his Materialism and Empirio-Criticism

"Freedom does not consist in the dream of independence from natural laws, but in the knowledge of these laws." -Lenin

Sartre seems to want to reject materialism altogether as inherently deterministic. But I think that atheistic existentialism could be described as looking at the world through a purely materialist lense. All that exists is matter in motion. The meaning we give to it is our own. Marxism has long rejected the hard-determinist views of mechanical materialism since Marx's thesis on Feurbach. Hence we Marxists see materialism as dialectically changing. Personally, I think existneitalism is in many ways just one big dialectic:

Thesis: Being
Antithesis: Nothingness(matter)
Synthesis: Becoming

Personally, I am a weak-determinist existentialist. I don't agree that we "are condemned to be free." I think that natural and physical science, as well as some aspects of social science, do determine some things, but they can't determine our essence or actions. I do believe that there is a reality external to our sensations (I'm not a strong-empiricist or phenomenologist). So really, it seems like the big argument was (as corny as it sounds) really just one big misunderstanding. Why can't existentialism function as a philosophy with weak-determinism? I think one can be a weak determinist, or compatibilist, and still be an existentialist.