If, as you say, technique largely depends on the state of science, science depends far more still on the state and the requirements of technique. If society has a technical need, that helps science forward more than ten universities. The whole of hydrostatics (Torricelli, etc.) was called forth by the necessity for regulating the mountain streams of Italy in the sixteenth and seventeenth centuries. We have only known anything reasonable about electricity since its technical applicability was discovered. But unfortunately it has become the custom in Germany to write the history of the sciences as if they had fallen from the skies. So with all the other accidents, and apparent accidents, of history. The further the particular sphere which we are investigating is removed from the economic sphere and approaches that of pure abstract ideology, the more shall we find it exhibiting accidents in its development, the more will its curve run in a zig-zag. So also you will find that the axis of this curve will approach more and more nearly parallel to the axis of the curve of economic development the longer the period considered and the wider the field dealt with. In Germany the greatest hindrance to correct understanding is the irresponsible neglect by literature of economic history. It is so hard, not only to disaccustom oneself of the ideas of history drilled into one at school, but still more to rake up the necessary material for doing so. Who, for instance, has read old G. von G lich, whose dry collection of material nevertheless contains so much stuff for the clarification of innumerable political facts! For the rest, the fine example which Marx has given in the Eighteenth Brumaire should already, I think, provide you fairly well with information on your questions, just because it is a practical example. I have also, I believe, already touched on most of the points in Anti-D hring I, Chapters 9-11, and II, 2-4, as well as in III, I, or Introduction, and then in the last section of Feuerbach. Please do not weigh each word in the above too carefully, but keep the connection in mind; I regret that I have not the time to work out what I am writing to you so exactly as I should be obliged to do for publication.
Letters: Marx-Engels Correspondence 1894