Philosophies fall into either one of two basic worldviews, Idealism or Materialism.

Idealism holds that reality is constructed by the mind independent of a material reality, that only mind (and/or spirit) is real.

Materialism states that there is a material/physical world that is independent of the mind, and that it is knowable through experience and observation.

Marx asserts that yes, there is a knowable material reality, but that reality is mediated by an ideologically constructed, and socially and culturally produced, ‘reality’.