Consciousness and Practice

According to Marx-Engels, Consciousness is a distinctively human characteristic the fundamental function of which is social and practical.  Their exposition of the concept in the German Ideology includes the following analysis:  "Where there exists a relationship, it exists for me: the animal does not enter into 'relations' with anything, it does not enter into any relation at all.  For the animal, its relation to other does not exist as a relation."  Now, the "for me" signifies a concept of Consciousness that is either Phenomenological or Epiphenomenal, in contrast with concepts in which the object of Consciousness is no mere appearance, but a reality, in itself.  So, implicit in the Consciousness of a relation is that it represents some indeterminable Species interaction, from which it follows that Class Consciousness is no more than a special case of such an representation, and that 'Revolution' is only an interpretation of some Species activity, as is the attribution to it of 'Necessity'.  But, the deeper problem for them is that such a concept of Consciousness lacks causal efficacy, so no Consciousness, and no degree of development of Class Consciousness, suffices to motivate the Proletariat to Revolution.  In other words, their concept of Consciousness may be a Consciousness of Practice, but it is not a Practical Consciousness.