"The dialectical mode of thinking, at least as I construe it, precludes closure of the argument at any particular point. The intriguing configurations of internal and external contradiction … force the argument to spin onwards and outwards to all manner of new terrain. The opening of new questions to be answered, new paths for enquiry to take, provokes simultaneously the re-evaluation of basic concepts -- such as value -- and the perpetual re-casting of the conceptual apparatus used to describe the world. Perhaps the most extraordinary insight to be gained from a careful study of Marx is the intricate fluidity of thought, the perpetual creation of new openings within the corpus of his writings. Strange, then, that bourgeois philosophers frequently depict Marxist science as a closed system, not amenable to the verification procedures with which they seek to close out their own hypotheses into universal and unchallengeable truths. Strange, also, that many Marxists convert deeply held and passionately felt commitments into doctrinaire dogmatism, as closed to new openings as traditional bourgeois modes of thought, when Marx's own work totally belies such closure."
David Harvey, The Limits to Capital