The political aspect

 

One of the greatest tactical mistakes of Karl Marx and Marxists generally was the failure to join forces with potential religious allies.  Imagine if the Democratic Party in the United States said that if you're religious, you're not allowed to be a democrat.  They'd be finished in a week.  Likewise, imagine if the Republicans said the same thing.  It would be automatic death for any political movement, but especially for a movement like Marxism, which claimed that "The emancipation of the working classes must be conquered by the working classes themselves," and thus sought to build a mass movement of the industrial proletariat.  Perhaps the prohibition of religion might be a more achievable tactic in a movement composed of highly educated elites - either professionals, aristocrats, or the bourgeoisie themselves.  But a purely secular workers' movement is doomed from the start.

Insisting upon atheism is not only politically untenable, it is also theoretically weak.  Now, don't get me wrong: I'm not saying that Marxist theory should have a grounding in theism - not at all.  But it seems a perfectly sensible position to me to say that a critical theory of political economy and the political movement that arises therefrom should be perfectly compatible with, yet in no way dependent upon, theism, religion, spirituality, and so on.  Actually, frankly, that goes for any economic, political, or scientific theory.  If you tell me that you have an economic theory, but that it requires you to believe in, or not to believe in, God or any particular religion, I would know right away that this is not a particularly good theory.  Belief or non-belief in God is immaterial to economic analysis - just as chemical analysis does not require anyone to believe, or not believe, in God.  And anyway, theories should not require you to believe, or not believe, in anything.  On the contrary, in science, it is up to us to evaluate the theories - it is not up to the theories to evaluate us.  If a theory is robust, it can stand on its own two feet, that is to say, on the evidence - it does not need any help from our emotional, ideal, abstract commitments.