> Marx says : 'The anatomy of man is a key to the anatomy of the ape.' The addition 'but not vice versa' would indeed be a bridge too far.
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> What Marx means is that it is easier to uncover the course of development from the starting point of the higher form, to see the important features in the lower (not that modern day Darwinians would use those terms). It wasn't actually a discussion of biology, but a biological analogy to explain the development of forms of property relations.
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> Far from being bullshit, it is rather good, as long as it is understood to describe the process of research, not the actual development itself.
The claim involves ontological and anthropological premises inconsistent with Darwinian biology. The latter is "materialist" in the sense dominant since Newton, i.e. in the sense that excludes any logical space for the ontological ideas of internal relations, final causation and self-determination and for the anthropological idea of human being as the being able to develop the rational self-consciousness (an idea itself requiring the ontological ideas for its self-consistent elaboration) able to know the "good" and actualize it in a truly "good" community.
These ideas are consistent with the fact of evolution, but provide an explanation for it that makes earlier forms fully understandable only in terms of later. This is because the later reveal the "essence" - the "in itself" - of the earlier, an "essence" that has, through a developmental process conceived within this "historical materialist" ontological and anthropological framework, revealed itself by becoming "for itself".
In Marx, this is an application of Hegel's idea that "reason governs the world". For him, as for Hegel, the "essence" of human being is "freedom", but only as the human "destiny".
"That man is free by Nature is quite correct in one sense; viz., that he is so according to the Idea of Humanity; but we imply thereby that he is such only in virtue of his destiny – that he has an undeveloped power to become such; for the 'Nature' of an object is exactly synonymous with its 'Idea.'" http://www.marxists.org/reference/archive/hegel/works/hi/history4.htm#042
Thus, that "communism" is the key to understanding human origins derives from the fact that the former was present in the latter as its "in itself", a fact that only becomes evident at the end of the developmental process through which it becomes "for itself".
"Communism as the positive transcendence of private property as human self-estrangement, and therefore as the real appropriation of the human essence by and for man; communism therefore as the complete return of man to himself as a social (i.e., human) being – a return accomplished consciously and embracing the entire wealth of previous development. This communism, as fully developed naturalism, equals humanism, and as fully developed humanism equals naturalism; it is the genuine resolution of the conflict between man and nature and between man and man – the true resolution of the strife between existence and essence, between objectification and self-confirmation, between freedom and necessity, between the individual and the species. Communism is the riddle of history solved, and it knows itself to be this solution
"||V| The entire movement of history, just as its [communism’s] actual act of genesis – the birth act of its empirical existence – is, therefore, for its thinking consciousness the comprehended and known process of its becoming." http://www.marxists.org/archive/marx/works/1844/manuscripts/comm.htm
That the ontological and anthropological ideas involved are inconsistent with the dominant form of "materialism" doesn't demonstrate that they are mistaken. Valid criticism has ultimately to be phenomenological.
Ted