It can be seen how subjectivism and objectivism, spiritualism and
materialism, activity and passivity lost their opposition and thus
their existence as opposites only in a social situation; it can be
seen how the solution of theoretical opposition is only possible in a
practical way, only through the practical energy of man, and their
solution is thus by no means an exercise in epistemology but a real
problem of life that philosophy could not solve just because it
coceived of it as a purely theoretical task.
--Marx, "Economic and Philosophic Manuscripts"

Reload for another.