I've never been impressed by the "crude materialist" (physicalist) view that everything can be reduced to "matter in motion." For me, "materialism" involves an emphasis on human practice in a historical process (stressing what people do over what they think or say) and an empirical orientation rather than a sole focus on idealized models or theories and their "elegance." (Of course, I'm not a reductionist: what people think or say is part of the picture, just as theories help us understand empirical reality.)
JD ^^^^^^^ CB: That crude materialist formulation - there is nothing in the world but matter and its mode of existence is motion - is from Engels. However, he is also a main source of the non-crude aspect of what you say: that practice is the test of theory. Engels is the main one to essay the emphasis on human practice in materialism, elaborating the principles in Marx's "Theses on Feuerbach". See _Socialism: Utopian and Scientific_ , _Feuerbach_ , Theses on Feuerbach, _Anti-Durhing_ and _Materialism and Empirio-Criticism_.
