Complex sentence: The "orthodoxy" in orthodox Marxism refers specifically to the methodology of historical materialism and dialectical materialism employed and not to any of the normative aspects inherent to classical Marxism; nor does it imply adherence to the results of Marx's own investigations.
Split into simpler sentences: The "orthodoxy" in orthodox Marxism specifically refers to the methodology of historical materialism and dialectical materialism employed and not to any of the normative aspects inherent to classical Marxism. "Orthodox" does not imply adherence to the results of Marx's own investigations.