“The chief defect of all previous materialism (...) is that things, reality, sensuousness, are conceived only in the form of the object, or contemplation, but not as sensuous human activity, practice, not subjectively....The active side was set forth abstractly by idealism....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-worldliness of his thinking in practice. The dispute over the reality or non-reality of thinking which is isolated from practice is a purely scholastic question....The philosophers have only interpreted the world in various ways; the
point is to change it.”
