Secular idealism, like religion, is preoccupied with what is intangible, ideal, or immaterial, which is somehow meant to be more real than material reality. It is another way of drawing a distinction between (1) a theoretical idea, which can be talked about and thought about but which cannot be touched because it will always be intangible, and (2) a practical, tangible, applied reality, which can be talked and thought about and in addition touched and directly experienced. In Marx's view, only what is tangible about experience is really worth talking or thinking about, and that would be the material conditions in which experience unfolds. That is in the background of this reference to objective truth:
The question whether objective truth can be attributed to human thinking is not a question of theory but is a practical question. Man must prove the truth, i.e., the reality and power, the this-sidedness [Diesseitigkeit] of his thinking, in practice. The dispute over the reality of non-reality of thinking which is isolated from practice is a purely scholastic question (Marx, Theses, p. 3)
In Marx's view, what is relevant is the truth: what is real, objective, tangible. The truth of experience is contained in the "activity and the material conditions under which [people] live, both those which they find already existing and those produced by their activity" (Marx, German, p. 3). Human beings are uniquely capable of producing their conditions by producing "their means of subsistence, a step which is conditioned by their physical organization" (p. 3). How they produce their subsistence is a feature of the conditions under which they do so. He sees these conditions emerging out of the historical process of social evolution.
Marx looks at (a) the facts of physical history and environment to find philosophical meaning, instead of (b) philosophical meanings or theories that are applied to the facts of physical history. That is the real diff...
Feuerbach's Idealism. (1969, December 31). In LotsofEssays.com. Retrieved 13:57, August 29, 2016, from http://www.collegetermpapers.com/viewpaper/1303922308.html