As palliation of my error I may mention that it was the opponents of capital themselves--and Marx in particular--who confirmed me in it, or, more correctly, who prevented me from distinctly perceiving the basis upon which interest essentially rests. To tear oneself away from long-cherished views is in itself extremely difficult; and when, moreover, the men who attack the old views base their attack point after point upon error, it becomes only too easy to mistake the weakness of the attack for impregnability in the thing attacked. Thus it happened with me. Because I saw that what had been hitherto advanced against capital and interest was altogether untenable, I felt myself absolved from the task of again and independently inquiring whether there were no better, no really valid, arguments against the absolute and permanent necessity of interest. Thus, though interest is, in reality, as little compatible with associated labour carried on upon the principle of perfect economic justice as are ground-rent and the undertaker's profit, I was prevented by this fundamental error from arriving at satisfactory views concerning the constitution and character of the future forms of organisation based upon the principle of free organisation. _That_ and _wherefore_ economic freedom and justice must eventually be practically realised, I had shown; on the other hand, _how_ this phase of evolution was to be brought about I was not able to make fully clear. Yet I did not ascribe this inability to any error of mine in thinking the subject out, but believed it to reside in the nature of the subject itself. I reasoned that institutions the practical shaping of which belongs to the future could not be known in detail before they were evolved. Just as those former generations, which knew nothing of the modern joint-stock company, could not possibly form an exact and perfect idea of the nature and working of this institution even if they had conceived the principle upon which it is based, so I held it to be impossible to-day to possess a clear and connected idea of those future economic forms which cannot be evolved until the principle of the free association of labour has found its practical realisation.