Idealism, Materialism, Theory, Practice

The idea of a chair can be derived from perceiving a chair, and a chair can be constructed on the basis of an idea of a chair.  Likewise, the idea of Socialism can guide the establishment of a Socialist state, and from the observation of a Socialist state, an idea of Socialism can be derived.  Furthermore, that idea is also a theory, for Marx an application of another theory, Materialism.  So, while his distinction between interpreting the world and changing the world is relatively clear-cut, the antitheses between Idealism and Practice, Theory and Practice, and Materialism and Theory, that he presumes upon to explain it, are not.