Changing the World and Changing Humans

Easy to overlook in Marx's contrast between interpreting the world and changing the world is their common object--"the world".  Now, it is not clear what exactly he means by the term, but it seems likely that it signifies the environment of humans, and, therefore, something distinct from humans.  But, if so, then his assertion that the point of philosophical activity hitherto is interpreting the world is at least partly false.  For, while among the standard fields, Metaphysics and Physics are studies of the world, Ethics, Psychology, and Politics are not--they are studies of Humankind.  Furthermore, the point of making public any such study is to communicate it to other humans, and, thus, to edify others in some respect.  Now, a theory-practice distinction can be drawn among such edifying subject matter, and Marx's exhortation consists in privileging the latter.  Therefore, his primary purpose is to change not the world, but Humankind.