> As I see, the main function of the labor theory of value was polemical - to
> support the claim that capitalists do not contribute any economic value,
> only the labor does, which in turn provided logical grounds for calling for
> 'expropriation of expropriators."
At the level of ontology and philosophical anthropology, it's the claim that "value" as the objectification of "self-conscious reason," i.e. of true aesthetic, intellectual and ethical "goods," is the objectification of "human" activity.
As an explanation of the exchange value of the "commodities" that constitute the appearance of "wealth" in capitalism as the objectification of estranged labour, it underpins "the law of the tendency of the rate of profit to fall."
This is then incorporated into the "dialectical" analysis of capitalism in terms of Hegel's "higher dialectic of the conception," an analysis that makes "reason" "the rose in the cross of the present" and "the business of science ... simply to bring the specific work of the reason, which is in the thing, to consciousness."
According to Marx (as his treatment of Ricardo's political economy in the passage I just quoted demonstrates), reason as the rose in the cross of the capitalist present is found in the fact that capitalism gives "the greatest impulse at once to the productive forces of social labour and to the integral development of every individual producer," i.e. is found in the fact that it gives "the greatest impulse" to the development and actualization of "self-conscious reason."
It's by doing this that capitalism "itself begets its own negation with the inexorability which governs the metamorphoses of nature" so that "capitalist property, resting as it actually does already on a form of collective production, cannot do other than transform itself into social property."
"Marxism" in almost all of its forms ignores this essential "dialectical" feature of Marx's "historical materialism," the feature that constitutes human history as "different stages in the development of the human mind."
One example is the Marxist "crisis" theory that, ignoring the wider ontological and anthropological framework of which it's part, reduces Marx's own theory to the bath water that is "the law of the tendency of the rate of profit to fall."
Ted