The real idealism of Feuerbach becomes evident as soon as we come to his philosophy of religion and ethics. He by no means wishes to abolish religion; he wants to perfect it. Philosophy itself must be absorbed in religion. “The periods of humanity are distinguished only by religious changes. A historical movement is fundamental only when it is rooted in the hearts of men. The heart is not a form of religion, so that the latter should exist also in the heart; the heart is the essence of religion” (quoted by Starcke, p. 168). According to Feuerbach, religion is the relation between human beings based on the affections, the relation based on the heart, which relation until now has sought its truth in a fantastic mirror image of reality—in the mediation of one or many gods, the fantastic mirror images of human qualities—but now finds it directly and without any mediation in the love between “I” and “Thou”. Thus, finally, with Feuerbach sex love becomes one of the highest forms, if not the highest form, of the practice of his new religion.
Now relations between human beings, based on affection, and especially between the two sexes, have existed as long as mankind has. Sex love in particular has undergone a development and won a place during the last eight hundred years which has made it a compulsory pivotal point of all poetry during this period. The existing positive religions have limited themselves to the bestowal of a higher consecration upon state-regulated sex love, that is, upon the marriage laws, and they could all disappear tomorrow without changing in the slightest the practice of love and friendship. Thus the Christian religion in France, as a matter of fact, so completely disappeared in the years 1793-98 that even Napoleon could not re-introduce it without opposition and difficulty; and this without any need for a substitute, in Feuerbach’s sense, making itself felt in the interval.
Feuerbach’s idealism consists here in this: he does not simply accept mutual relations based on reciprocal inclination between human beings, such as sex love, friendship, compassion, self-sacrifice, etc., as what they are in themselves—without associating them with any particular religion which to him, too, belongs to the past; but instead he asserts that they will attain their full value only when consecrated by the name of religion. The chief thing for him is not that these purely human relations exist, but that they shall be conceived of as the new, true religion. They are to have full value only after they have been marked with a religious stamp. Religion is derived from religare  and meant originally a bond. Therefore, every bond between two people is a religion. Such etymological tricks are the last resort of idealist philosophy. Not what the word means according to the historical development of its actual use, but what it ought to mean according to its derivation is what counts. And so sex love and the intercourse between the sexes is apotheosised to a religion, merely in order that the word religion, which is so dear to idealistic memories, may not disappear from the language. The Parisian reformers of the Louis Blanc trend used to speak in precisely the same way in the forties. They likewise could conceive of a man without religion only as a monster, and used to say to us: “Donc, l’athéisme c’est votre religion!”  If Feuerbach wishes to establish a true religion upon the basis of an essentially materialist conception of nature, that is the same as regarding modern chemistry as true alchemy. If religion can exist without its god, alchemy can exist without its philosopher’s stone. By the way, there exists a very close connection between alchemy and religion. The philosopher’s stone has many godlike properties and the Egyptian-Greek alchemists of the first two centuries of our era had a hand in the development of Christian doctrines, as the data given by Kopp and Berthelot have proved.
Feuerbach’s assertion that “the periods of humanity are distinguished only by religious changes” is decidedly false. Great historical turning-points have been accompanied by religious changes only so far as the three world religions which have existed up to the present—Buddhism, Christianity and Islam—are concerned. The old tribal and national religions, which arose spontaneously, did not proselytise and lost all their power of resistance as soon as the independence of the tribe or people was lost. For the Germans it was sufficient to have simple contact with the decaying Roman world empire and with its newly adopted Christian world religion which fitted its economic, political and ideological conditions. Only with these world religions, arisen more or less artificially, particularly Christianity and Islam, do we find that the more general historical movements acquire a religious imprint. Even in regard to Christianity the religious stamp in revolutions of really universal significance is restricted to the first stages of the bourgeoisie’s struggle for emancipation—from the thirteenth to the seventeenth century—and is to be accounted for, not as Feuerbach thinks by the hearts of men and their religious needs, but by the entire previous history of the Middle Ages, which knew no other form of ideology than religion and theology. But when the bourgeoisie of the eighteenth century was strengthened enough likewise to possess an ideology of its own, suited to its own class standpoint, it made its great and conclusive revolution, the French, appealing exclusively to juristic and political ideas, and troubling itself with religion only in so far as it stood in its way. But it never occurred to it to put a new religion in place of the old. Everyone knows how Robespierre failed in his attempt. 
The possibility of purely human sentiments in our intercourse with other human beings has nowadays been sufficiently curtailed by the society in which we must live, which is based upon class antagonism and class rule. We have no reason to curtail it still more by exalting these sentiments to a religion. And similarly the understanding of the great historical class struggles has already been sufficiently obscured by current historiography, particularly in Germany, so that there is also no need for us to make such an understanding totally impossible by transforming the history of these struggles into a mere appendix of ecclesiastical history.
Already here it becomes evident how far today we have moved beyond Feuerbach. His “finest passages” in glorification of his new religion of Jove are totally unreadable today.
The only religion which Feuerbach examines seriously is Christianity, the world religion of the Occident, based upon monotheism. He proves that the Christian god is only a fantastic reflection, a mirror image, of man. Now, this god is, however, himself the product of a tedious process of abstraction, the concentrated quintessence of the numerous earlier tribal and national gods. And man, whose image this god is, is therefore also not a real man, but likewise the quintessence of the numerous real men, man in the abstract, therefore himself again a mental image. Feuerbach, who on every page preaches sensuousness, absorption in the concrete, in actuality, becomes thoroughly abstract as soon as he begins to talk of any other than mere sex relations between human beings.
Of these relations only one aspect appeals to him: morality. And here we are again struck by Feuerbach’s astonishing poverty when compared with Hegel. The latter’s ethics, or doctrine of moral conduct, is the philosophy of right and embraces: (1) abstract right; (2) morality; (3) social ethics [Sittlichkeit], under which again are comprised: the family, civil society and the state. Here the content is as realistic as the form is idealistic. Besides morality the whole sphere of law, economy, politics is here included. With Feuerbach it is just the reverse. In form he is realistic since he takes his start from man; but there is absolutely no mention of the world in which this man lives; hence, this man remains always the same abstract man who occupied the field in the philosophy of religion. For this man is not born of woman; he issues, as from a chrysalis, from the god of the monotheistic religions. He therefore does not live in a real world historically come into being and historically determined. True, he has intercourse with other men; however, each one of them is just as much an abstraction as he himself. In his philosophy of religion we still had men and women, but in his ethics even this last distinction disappears. Feuerbach, to be sure, at long intervals makes such statements as: “Man thinks differently in a palace and in a hut.” “If because of hunger, of misery, you have no stuff in your body, you likewise have no stuff for morality in your head, in your mind or heart.” “Politics must become our religion,” etc. But Feuerbach is absolutely incapable of achieving anything with these maxims. They remain mere phrases, and even Starcke has to admit that for Feuerbach politics constituted an impassable frontier and the “science of society, sociology, was terra incognita to him”.
He appears just as shallow, in comparison with Hegel, in his treatment of the antithesis of good and evil. “One believes one is saying something great,” Hegel remarks, “if one says that ‘man is naturally good’. But one forgets that one says something far greater when one says ‘man is naturally evil’.” With Hegel evil is the form in which the motive force of historical development presents itself. This contains the twofold meaning that, on the one hand, each new advance necessarily appears as a sacrilege against things hallowed, as a rebellion against conditions, though old and moribund, yet sanctified by custom; and that, on the other hand, it is precisely the wicked passions of man—greed and lust for power—which, since the emergence of class antagonisms, serve as levers of historical development—a fact of which the history of feudalism and of the bourgeoisie, for example, constitutes a single continual proof. But it does not occur to Feuerbach to investigate the historical role of moral evil. To him history is altogether an uncanny domain in which he feels ill at ease. Even his dictum: “Man as he sprang originally from nature was only a mere creature of nature, not a man. Man is a product of man, of culture, of history”—with him even this dictum remains absolutely sterile.
What Feuerbach has to tell us about morals can, therefore, only be extremely meagre. The urge towards happiness is innate in man, and must therefore form the basis of all morality. But the urge towards happiness is subject to a double correction. First, by the natural consequences of our actions: after the debauch come the “blues”, and habitual excess is followed by illness. Secondly, by its social consequences: if we do not respect the similar urge of other people towards happiness they will defend themselves, and so interfere with our own urge towards happiness. Consequently, in order to satisfy our urge, we must be in a position to appreciate rightly the results of our conduct and must likewise allow others an equal right to seek happiness. Rational self- restraint with regard to ourselves, and love—again and again love!—in our intercourse with others—these are the basic laws of Feuerbach’s morality; from them all others are derived. And neither the most spirited utterances of Feuerbach nor the strongest eulogies of Starcke can hide the tenuity and banality of these few propositions.
Only very exceptionally, and by no means to his and other people’s profit, can an individual satisfy his urge towards happiness by preoccupation with himself. Rather it requires preoccupation with the outside world, with means to satisfy his needs, that is to say, food, and individual of the opposite sex, books, conversation, argument, activities, objects for use and working up. Feuerbach’s morality either presupposes that these means and objects of satisfaction are given to every individual as a matter of course, or else it offers only inapplicable good advice and is, therefore, not worth a brass farthing to people who are without these means. And Feuerbach himself states this in plain terms: “Man thinks differently in a palace and in a hut. If because of hunger, of misery, you have no stuff in your body, you likewise have no stuff for morality in your head, in your mind or heart.”
Do matters fare any better in regard to the equal right of others to satisfy their urge towards happiness? Feuerbach posed this claim as absolute, as holding good for all times and circumstances. But since when has it been valid? Was there ever in antiquity between slaves and masters, or in the Middle Ages between serfs and barons, any talk about an equal right to the urge towards happiness? Was not the urge towards happiness of the oppressed class sacrificed ruthlessly and “by right of law” to that of the ruling class? Yes, that was indeed immoral; nowadays, however, equality of rights is recognised. Recognised in words ever since and inasmuch as the bourgeoisie, in its fight against feudalism and in the development of capitalist production, was compelled to abolish all privileges of estate, that is, personal privileges, and to introduce the equality of all individuals before the law, first in the sphere of private law, then gradually also in the sphere of public law. But the urge towards happiness thrives only to a trivial extent on ideal rights. To the greatest extent of all it thrives on material means; and capitalist production takes care to ensure that the great majority of those with equal rights shall get only what is essential for bare existence. Capitalist production has, therefore, little more respect, if indeed any more, for the equal right to the urge towards happiness of the majority than had slavery or serfdom. And are we better off in regard to the mental means of happiness, the educational means? Is not even “the schoolmaster of Sadowa”  a mythical person?
More. According to Feuerbach’s theory of morals the Stock Exchange is the highest temple of moral conduct, provided only that one always speculates right. If my urge towards happiness leads me to the Stock Exchange, and if there I correctly gauge the consequences of my actions so that only agreeable results and no disadvantages ensue, that is, if I always win, then I am fulfilling Feuerbach’s precept. Moreover, I do not thereby interfere with the equal right of another person to pursue his happiness; for that other man went to the Exchange just as voluntarily as I did and in concluding the speculative transaction with me he has followed his urge towards happiness as I have followed mine. If he loses his money, his action is ipso facto proved to have been unethical, because of his bad reckoning, and since I have given him the punishment he deserves, I can even slap my chest proudly, like a modern Rhadaman-thus. Love, too, rules on the Stock Exchange, in so far as it is not simply a sentimental figure of speech, for each finds in others the satisfaction of his own urge towards happiness, which is just what love ought to achieve and how it acts in practice. And if I gamble with correct prevision of the consequences of my operations, and therefore with success, I fulfil all the strictest injunctions of Feuerbachian morality—and become a rich man into the bargain. In other words, Feuerbach’s morality is cut exactly to the pattern of modern capitalist society, little as Feuerbach himself might desire or imagine it.
But love!—yes, with Feuerbach love is everywhere and at all times the wonder-working god who should help to surmount all difficulties of practical life—and at that in a society which is split into classes with diametrically opposite interests. At this point the last relic of its revolutionary character disappears from his philosophy, leaving only the old cant: Love one another—fall into each other’s arms regardless of distinctions of sex or estate—a universal orgy of reconciliation!
In short, the Feuerbachian theory of morals fares like all its predecessors. It is designed to suit all periods, all peoples and all conditions, and precisely for that reason it is never and nowhere applicable. It remains, as regards the rear world, as powerless as Kant’s categorical imperative. In reality every class, even every profession, has its own morality, and even this it violates whenever it can do so with impunity. And love, which is to unite all, manifests itself in wars, altercations, lawsuits, domestic broils, divorces and every possible exploitation of one by another.
Now how was it possible that the powerful impetus given by Feuerbach turned out to be so unfruitful for himself? For the simple reason that Feuerbach himself never contrives to escape from the realm of abstraction—for which he has a deadly hatred—into that of living reality. He clings fiercely to nature and man; but nature and man remain mere words with him. He is incapable of telling us anything definite either about real nature or real men. But from the abstract man of Feuerbach one arrives at real living men only when one considers them as participants in history. And that is what Feuerbach resisted, and therefore the year 1848, which he did not understand, meant to him merely the final break with the real world, retirement into solitude. The blame for this again falls chiefly on the conditions then obtaining in Germany, which condemned him to rot away miserably.
But the step which Feuerbach did not take had nevertheless to be taken. The cult of abstract man, which formed the kernel of Feuerbach’s new religion, had to be replaced by the science of real men and of their historical development. This further development of Feuerbach’s standpoint beyond Feuerbach was inaugurated by Marx in 1845 in The Holy Family.
Religare: To bind.—Ed.
“Well, then atheism is your religion!”—Ed.
The reference is to Robespierre’s attempt to set up a religion of the “highest being”.—Ed.
The schoolmaster of Sadowa: An expression currently used by German bourgeois publicists after the victory of the Prussians at Sadowa (in the Austro-Prussian War of 1866), the implication being that the Prussian victory was to be attributed to the superiority of the Prussian system of public education.—Ed.