Is the first quote only true in principle, while the second is true in practice; did Marx feel, in principle, that accessibility (which I would assume implies argumentative transparency) to workers is the paramount consideration, while actually in practice being led by his ego, or whatever, to play intellectual cat-and-mouse games with bourgeois economists?
Maybe. I think he tried to improve the acessibility and transparency multiple times (the different editions of and appendices to Capital; the abridged version by Most), but to no great success. Marx had great expectations about the theoretical uproar his work would cause (already when writing A Contribution), but these hopes were in vain – even his German socialist friends were clueless about why A Contribution could be important when it was published. I think this caused a lot of frustration on Marx's part.
And isn't the usual explanation for the somewhat a priori appearance of the opening chapter that the claims he was making were uncontroversial, that he was basically just summing up the Ricardian theory of the day? If I remember correctly that's David Harvey's explanation.
Yes, I agree with this. The commodity (and the two "factors", use-value and exchange value) he starts with basically goes back to Aristotle, and of course to Smith and Ricardo. (The first chapter in Ricardo's Principles is similar to Marx's).



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