Proudhon to Marx
Let us seek together, if you wish, the laws of society, the manner in which these laws are realized, the process by which we shall succeed in discovering them; but, for God’s sake, after having demolished all the a priori dogmatisms, do not let us in our turn dream of indoctrinating the people; do not let us fall into the contradiction of your compatriot Martin Luther, who, having overthrown Catholic theology, at once set about, with excommunication and anathema, the foundation of a Protestant theology. For the last three centuries Germany has been mainly occupied in undoing Luther’s shoddy work; do not let us leave humanity with a similar mess to clear up as a result of our efforts. I applaud with all my heart your thought of bringing all opinions to light; let us carry on a good and loyal polemic; let us give the world an example of learned and far-sighted tolerance, but let us not, merely because we are at the head of a movement, make ourselves the leaders of a new intolerance, let us not pose as the apostles of a new religion, even if it be the religion of logic, the religion of reason. Let us gather together and encourage all protests, let us brand all exclusiveness, all mysticism; let us never regard a question as exhausted, and when we have used our last argument, let us begin again, if need be, with eloquence and irony. On that condition, I will gladly enter your association. Otherwise — no!
Emphases mine. Edmund Wilson: “The result of this incident was that Marx was to set upon Proudhon’s new book with a ferocity entirely inconsonant with the opinion of the value of Proudhon’s earlier work which he had expressed and which he was to reiterate later” (To the Finland Station, p. 154).