Hartmann and Guyau[29] have shown that the evolution of religious beliefs may be summarized thus:  All religions include, with various other matters, the promise of happiness; but the primitive religions concede that this happiness will be realized during the life of the individual himself, and the later religions, through an excess of reaction, place its realization after death, outside the human world; in the final phase, this realization of happiness is once more placed within the field of human life, no longer in the ephemeral moment of the individual existence, but indeed in the continuous evolution of all mankind.

On this side, then, socialism is closely related to the religious evolution, and tends to substitute itself for religion, since its aim is for humanity to have its own “earthly paradise” here, without having to wait for it in the hereafter, which, to say the least, is very problematical.

Therefore, it has been very justly remarked that the socialist movement has many traits in common with, for example, primitive Christianity, notably that ardent faith in the ideal that has definitively deserted the arid field of bourgeois skepticism, and some savants, not socialists, such as Messrs. Wallace, de Lavaleye and the Roberty, etc., admit that it is entirely possible for socialism to replace by its humanitarian faith the faith in the hereafter of the former religions.

More direct and potent than these relations (between socialism and faith in a hereafter) are, however, the relations which exist between socialism and the belief in God.

It is true that Marxian Socialism, since the Congress held at Erfurt (1891), has rightly declared that religious beliefs are private affairs[30] and that, therefore, the Socialist party combats religious intolerance under all its forms, whether it be directed against Catholics[31] or against Jews, as I have shown in an article against Anti-Semitism.[32] But this breadth of superiority of view is, at bottom, only a consequence of the confidence in final victory.

It is because socialism knows and foresees that religious beliefs, whether one regards them, with Sergi,[33] as pathological phenomena of human psychology, or as useless phenomena of moral incrustation, are destined to perish by atrophy with the extension of even elementary scientific culture.  This is why socialism does not feel the necessity of waging a special warfare against these religious beliefs which are destined to disappear.  It has assumed this attitude although it knows that the absence or the impairment of the belief in God is one of the most powerful factors for its extension, because the priests of all religions have been, throughout all the phases of history, the most potent allies of the ruling classes in keeping the masses pliant and submissive under the yoke by means of the enchantment of religion, just as the tamer keeps wild beasts submissive by the terrors of the cracks of his whip.