It’s common for Marxists and others in the ‘class-struggle tradition’ often speak of themselves as ‘materialists’, talk about a ‘materialist worldview’ or ‘materialist philosophy’.
When pressed, what this turns out to mean is something like: there is only one world, subject to a single set of laws; human beings have evolved in this world according to that same set of laws, and there is no personal afterlife or an intelligent creator. In a phrase: ‘animal consciousness is a tautology.
Thing is, in philosophy, this position and worldview would be best described not by the term ‘materialism’ but by the term ‘naturalism’. The catchy slogan about ‘animal consciousness’ above, for instance, comes from Schopenhauer, a philosopher who is arguably naturalist but certainly not materialist.
‘Materialism’ adds the odd claim that the single basic type of stuff in the universe is something called ‘matter’, a claim which is either trivial (if matter is defined as ‘whatever exists’) or dogmatic and probably false (if matter is defined in some other way – as mathematical, as having mass, as not being conscious, etc). Maybe all of these commies are actually materialists in the stronger sense, but it would seem odd, especially since they are generlly keen to disparage metaphysics and abstract speculation, which is what the assertion of materialism proper would be.
Does this matter? Well, not very much. But I do think it’s unfortunate to have people in different arenas who, on this philosophical point, largely agree, using different, and potentially confusing, words.