Idealism and Practice

For Plato, Idealism has Epistemological, Ontological, and Moral dimensions.  An Idea is that through which particulars are known; the world of Ideas is Real, with respect to which the world of their instantiations is irreal; and an Idea is an Ideal, i. e. is a perfection, with respect to which its instantiations are deficient.  Now, while the first dimension, somewhat modified, has apparently survived the most in Modern Philosophy, the other two have been useful to formalizing the main relations in the Creator-Creation concept of religions such as Christianity.  But, Marx's immediate target in his inversion of 'Idealism' is specifically the Ontological dimension, e. g. 'Heaven', which he exposes as derived from 'Earth', and, so, as not Real, in the Platonist sense.  In the process, he does not recognize his own transposition of the other two functions into the context of Practice--an Idea as illuminating a course of Action, and, insofar as a course of Action aims to better preceding conditions, its guiding light can be an Ideal, as well.  For example, Socialism serves him as both an Idea and an Ideal, demonstrating that he does not consider that he himself incorporates a Practical Idealism into his works.