A letter to Johann Baptist von Schweitzer, written shortly after Proudhon’s death, in reply to a demand, summarizing Marx’s critique of Proudhon’s petit bourgeois attitude and intellectual errors. Published in Der Sozialdemokrat in February 1865.
Yesterday I received a letter in which you demand from me a detailed judgment of Proudhon. Lack of time prevents me from fulfilling your desire. Added to which I have none of his works to hand. However, in order to assure you of my good will I will quickly jot down a brief outline. You can then complete it, add to it or cut it — in short do anything you like with it. 
Proudhon’s earliest efforts I no longer remember. His school work about the langue universelle shows how unceremoniously he tackled problems for the solution of which he still lacked the first elements of knowledge.
His first work, What Is Property?, is undoubtedly his best. It is epoch-making, if not because of the novelty of its content, at least because of the new and audacious way of expressing old ideas. In the works of the French socialists and communists he knew “propriété” had, of course, been not only criticized in various ways but also “aufgehoben” [abolished or sublated] in a utopian manner. In this book Proudhon stands in approximately the same relation to Saint-Simon and Fourier as Feuerbach stands to Hegel. Compared with Hegel, Feuerbach is certainly poor. Nevertheless he was epoch-making after Hegel because he laid stress on certain points which were disagreeable to the Christian consciousness but important for the progress of criticism, points which Hegel had left in mystic clair-obscur [semi-obscurity].
In this book of Proudhon’s there still prevails, if I may be allowed the expression, a strong muscular style. And its style is in my opinion its chief merit. It is evident that even where he is only reproducing old stuff, Proudhon discovers things in an independent way — that what he is saying is new to him and is treated as new. The provocative defiance, which lays hands on the economic “holy of holies,” the ingenious paradox which made a mock of the ordinary bourgeois understanding, the withering criticism, the bitter irony, and, revealed here and there, a deep and genuine feeling of indignation at the infamy of the existing order, a revolutionary earnestness — all these electrified the readers of What Is Property? and provided a strong stimulus on its first appearance. In a strictly scientific history of political economy the book would hardly be worth mentioning. But sensational works of this kind have their role to play in the sciences just as much as in the history of the novel. Take, for instance, Malthus’s book An Essay on the Principle of Population. Its first edition was nothing but a “sensational pamphlet” and plagiarism from beginning to end into the bargain. And yet what a stimulus was produced by this lampoon on the human race!
If I had Proudhon’s book before me I could easily give a few examples to illustrate his early style. In the passages which he himself regarded as the most important he imitates Kant’s treatment of the antinomies — Kant was at that time the only German philosopher whose works he had read, in translations — and he leaves one with a strong impression that to him, as to Kant, the resolution of the antinomies is something “beyond” human understanding, i.e., something that remains obscure to him himself.
But in spite of all his apparent iconoclasm one already finds in What Is Property? the contradiction that Proudhon is criticizing society, on the one hand, from the standpoint and with the eyes of a French small-holding peasant (later petit bourgeois) and, on the other, that he measures it with the standards he inherited from the socialists.
The deficiency of the book is indicated by its very title. The question is so badly formulated that it cannot be answered correctly. Ancient “property relations” were superseded by feudal property relations and the feudal by “bourgeois” property relations. Thus history itself had expressed its criticism upon past property relations. What Proudhon was actually dealing with was modern bourgeois property as it exists today. The question of what this is could have only been answered by a critical analysis of “political economy,” embracing the totality of these property relations, considering not their legal aspect as relations of volition but their real form, that is, as relations of production. But as Proudhon entangled the whole of these economic relations in the general legal concept of “property”, “la propriété”, he could not get beyond the answer which, in a similar work published before 1789, Brissot had already given in the same words: “La propriété c’est le vol” [“Property is theft”].
The upshot is at best that the bourgeois legal conceptions of “theft” apply equally well to the “honest” gains of the bourgeois himself. On the other hand, since “theft” as a forcible violation of property presupposes the existence of property, Proudhon entangled himself in all sorts of fantasies, obscure even to himself, about true bourgeois property.
During my stay in Paris in 1844 I came into personal contact with Proudhon. I mention this here because to a certain extent I am also to blame for his “sophistication,” as the English call the adulteration of commercial goods. In the course of lengthy debates often lasting all night, I infected him very much to his detriment with Hegelianism, which, owing to his lack of German, he could not study properly. After my expulsion from Paris Mr. Karl Grün continued what I had begun. As a teacher of German philosophy he also had the advantage over me that he himself understood nothing about it.
Shortly before the appearance of Proudhon’s second important work, The Philosophy of Poverty, he himself announced this to me in a very detailed letter in which he said, among other things: “J’attends votre férule critique” [“I await your harsh critique”]. This criticism, however, soon dropped on him (in my Poverty of Philosophy), in a way which ended our friendship forever.
From what I have said here, you can see that Proudhon’s The System of Economic Contradictions, or The Philosophy of Poverty first contained the real answer to the question What Is Property?. In fact it was only after the publication of this work that he had begun his economic studies; he had discovered that the question he had raised could not be answered by invective, but only by an analysis of modern “political economy.” At the same time he attempted to present the system of economic categories dialectically. In place of Kant’s insoluble “antinomies,” the Hegelian “contradiction” was to be introduced as the means of development. For an estimate of his book, which is in two fat volumes, I must refer you to the refutation I wrote. There I have shown, among other things, how little he had penetrated into the secret of scientific dialectics and how, on the contrary, he shares the illusions of speculative philosophy, for instead of regarding economic categories as the theoretical expression of historical relations of production, corresponding to a particular stage of development in material production, he garbles them into pre-existing eternal ideas, and how in this roundabout way he arrives once more at the standpoint of bourgeois economy. 
I show furthermore how extremely deficient and at times even schoolboy-like is his knowledge of “political economy” which he undertook to criticize, and that he and the utopians are hunting for a so-called “science” by means of which a formula for the “solution of the social question” is to be devised a priori, instead of deriving science from a critical knowledge of the historical movement, a movement which itself produces the material conditions of emancipation. My refutation shows in particular that Proudhon’s view of exchange-value, the basis of the whole theory, remains confused, incorrect and superficial, and that he even mistakes the utopian interpretation of Ricardo’s theory of value for the basis of a new science. With regard to his general point of view I have summarized my conclusions thus:
Every economic relation has a good and a bad side, it is the one point on which Mr. Proudhon does not give himself the lie. He sees the good side expounded by the economists; the bad side he sees denounced by the socialists. He borrows from the economists the necessity of eternal relations; he borrows from the socialists the illusion of seeing in poverty nothing but poverty (instead of seeing in it the revolutionary, destructive aspect which will overthrow the old society). He is in agreement with both in wanting to fall back upon the authority of science. Science for him reduces itself to the slender proportions of a scientific formula; he is the man in search of formulas. Thus it is that Mr. Proudhon flatters himself on having given a criticism of both political economy and of communism: he is beneath them both. Beneath the economists, since as a philosopher who has at his elbow a magic formula, he thought he could dispense with going into purely economic details; beneath the socialists, because he has neither courage enough nor insight enough to rise, be it even speculatively, above the bourgeois horizon […]. He wants to soar as the man of science above the bourgeois and the proletarians; he is merely the petty bourgeois, continually tossed back and forth between capital and labour, political economy and communism.
Severe though the above judgment may sound I must even now endorse every word of it. At the same time, however, one has to bear in mind that when I declared his book to be the code of socialism of the petit bourgeois and proved this theoretically, Proudhon was still being decried as an ultra-arch-revolutionary both by political economists and by socialists. That is why later on I never joined in the outcry about his “treachery” to the revolution. It was not his fault that, originally misunderstood by others as well as by himself, he failed to fulfil unjustified hopes.
In the The Philosophy of Poverty all the defects of Proudhon’s method of presentation stand out very unfavourably in comparison with What Is Property?. The style is often what the French call ampoule [bombastic]. High-sounding speculative jargon, purporting to be German-philosophical, appears regularly on the scene when his Gallic astuteness fails him. A noisy, self-glorifying, boastful tone and especially the twaddle about “science” and sham display of it, which are always so unedifying, are continually jarring on one’s ears. Instead of the genuine warmth which permeates his first work, he here systematically works himself up into a sudden flush of rhetoric in certain passages. There is in addition the clumsy repugnant show of erudition of the self-taught, whose natural pride in his original reasoning has already been broken and who now, as a parvenu of science, feels it necessary to give himself airs with what he neither is nor has. Then the mentality of the petty bourgeois who for instance makes an indecently brutal attack, which is neither shrewd nor profound nor even correct, on a man like Cabet — worthy of respect for his practical attitude towards the French proletariat — and on the other hand pays compliments to a man like Dunoyer (a “State Councillor,” it is true) although the whole significance of this Dunoyer lay in the comic zeal with which, throughout three fat, unbearably boring volumes, he preached a rigorism characterised by Helvetius as follows: “On veut que les malheureux soient parfaits” [We want the wretched to be perfect].
The February Revolution certainly came at a very inconvenient moment for Proudhon, who had irrefutably proved only a few weeks before that “the era of revolutions” was past for ever. His speech in the National Assembly, however little insight it showed into existing conditions, was worthy of every praise. After the June insurrection it was an act of great courage. In addition it had the fortunate consequence that Mr. Thiers, by his reply opposing Proudhon’s proposals, which was then issued as a special booklet, proved to the whole of Europe what infantile catechism served this intellectual pillar of the French bourgeoisie as a pedestal. Compared with Mr. Thiers, Proudhon indeed swelled to the size of an antediluvian colossus.
Proudhon’s discovery of “interest-free loans” [“crédit gratuit”], and the “people’s bank” [“banque du peuple”] based upon, it were his last economic “deeds.” My book A Contribution to the Critique of Political Economy, Part I contains the proof that the theoretical basis of his idea arises from a misunderstanding of the basic elements of bourgeois “political economy,” namely of the relation between commodities and money, while the practical superstructure was simply a reproduction of much older and far better developed schemes. That under certain economic and political conditions the credit system can be used to accelerate the emancipation of the working class, just as, for instance, at the beginning of the eighteenth, and again later, at the beginning of the nineteenth century in England, it facilitated the transfer of wealth from one class to another, is quite unquestionable and self-evident. But to regard interest-bearing capital as the main form of capital, and to try to make a particular form of the credit system comprising the alleged abolition of interest the basis for a transformation of society, is an out-and-out petty-bourgeois fantasy. This fantasy, further diluted, can therefore actually already be found among the economic spokesmen of the English petty bourgeoisie in the seventeenth century. Proudhon’s polemic with Bastiat (1850) about interest-bearing capital is on a far lower level than the Philosophy of Poverty. He succeeds in getting himself beaten even by Bastiat and breaks into burlesque bluster when his opponent drives his blows home.
A few years ago Proudhon wrote a prize essay on taxation — the competition was sponsored, I believe, by the government of Lausanne. Here the last flicker of genius is extinguished. Nothing remains but the petit bourgeois tout pur [pure, distilled petty bourgeois].
So far as Proudhon’s political and philosophical writings are concerned they all show the same contradictory, dual character as his economic works. Moreover their value is purely local, confined to France. Nevertheless his attacks on religion, the church, etc., were of great merit locally at a time when the French socialists thought it desirable to show by their religiosity how superior they were to the bourgeois Voltairianism of the eighteenth century and the German godlessness of the nineteenth. Just as Peter the Great defeated Russian barbarism by barbarity, Proudhon did his best to defeat French phrase-mongering by phrases.
His work on the Coup d’état, in which he flirts with Louis Bonaparte and, in fact, strives to make him palatable to the French workers, and his last work, written against Poland, in which for the greater glory of the tsar he expresses moronic cynicism, must be described as works not merely bad but base, a baseness, however, which corresponds to the petty-bourgeois point of view.
Proudhon has often been compared to Rousseau. Nothing could be more erroneous. He is more like Nicolas Linguet, whose Théorie des loix civiles [Theory of Civil Law], by the way, is a very brilliant book.
Proudhon had a natural inclination for dialectics. But as he never grasped really scientific dialectics he never got further than sophistry. This is in fact connected with his petty-bourgeois point of view. Like the historian Raumer, the petty bourgeois is made up of on-the-one-hand and on-the-other-hand. This is so in his economic interests and therefore in his politics, religious, scientific and artistic views. And likewise in his morals, in everything.  He is a living contradiction. If, like Proudhon, he is in addition an ingenious man, he will soon learn to play with his own contradictions and develop them according to circumstances into striking, ostentatious, now scandalous now brilliant paradoxes. Charlatanism in science and accommodation in politics are inseparable from such a point of view. There remains only one governing motive, the vanity of the subject, and the only question for him, as for all vain people, is the success of the moment, the éclat of the day. Thus the simple moral sense, which always kept a Rousseau, for instance, from even the semblance of compromise with the powers that be, is bound to disappear.
Posterity will perhaps sum up the latest phase of French development by saying that Louis Bonaparte was its Napoleon and Proudhon its Rousseau-Voltaire.
You yourself have now to accept responsibility for having imposed upon me the role of a judge of the dead so soon after this man’s death.
Yours very respectfully,
 We found it better to print the letter without any changes. — Der Sozialdemokrat.
 “When the economists say that present-day relations — the relations of bourgeois production — are natural, they imply that these are the relations in which wealth is created and productive forces developed in conformity with the laws of nature. These relations therefore are themselves natural laws independent of the influence of time. They are eternal laws which must always govern society. Thus there has been history, but there is no longer any.” (p. 113 of my work).
 Originally in English.