Herbert Marcuse on Dialectical Logic

In order to really know an object, one must grasp and investigate all sides of the object, all its relations and 'mediations' ... Second, dialectical logic requires that the object be taken in its development, in its 'self-movement' ... in its transformation. Third, the whole of human praxis must enter into the 'definition' of the object, as well as the critique of its truth, since as a practical determination the object is bound together with what is necessary to man. Fourth, the dialectical logic teaches that 'there is no abstract truth'; truth is always concrete.

Cit Douglas Kellner (1984), Herbert Marcuse and the Crisis of Marxism, p.52.