“Religion . . . is the opium of the people ” (Marx, 1975: 244). That is probably Marx's best-known remark about religion; indeed, perhaps it is the best-known statement of all. In the popular reception of Marx this observation is supposed to embody all that is known of his unremitting hostility to religion, especially to Christianity. Yet even taken on its own and out of context, it is a decidedly ambiguous remark, full of hidden complexities. I doubt if anything much is known about Marx's attitude toward the widespread habit of opium taking in his day, but if the practice of religion is meant to be analogous to drug taking, it is likely that he at least thought that both practices needed to be explained and not merely explained away.

Presumably Marx thought that drugs were taken as a source of illusions and hallucinations and also as a palliative, a form of consolatory flight from the harshness of the real world. Religion, he points out in the same passage, is the “illusory happiness of the people.” So if we are to explain the practice, we need to know not just why partakers personally like drug-induced illusions but also, and more fundamentally, why in the first place, users perceive the need to fly from the real world into illusions. For “religious suffering,” Marx continues, “is the expression of real suffering.“ That being the case, we should explain what it is about the real world itself that provokes the need to flee from it into religious illusions.