Dietzgen's philosophy is monistic in nature. This study is focused on the question in what way Dietzgen treats the relation between unity and diversity as an epistemological and ontological issue. How does Dietzgen formulate the unity of all that exists, and what is the place and the role of the process of gaining knowledge in this formulation? These questions serve as stepping stones to the central question: What is the position of Dieagen's thinking with regard to the philosophy of Feuerbach, (...) and that of Marx and Engels? This is an important question in the light of the history of the labour movement. In the early years of this century, Dietzgen's work became a subject of discussion. Some said that Dietzgen had nothing to add to Feuerbach's philosophy; others regarded him as the perfect Marxist philosopher. This discussion has not ended. The present study seeks to clarify the positions in this discussion by means of an analysis of Dietzgen's philosophy itself. This raises the additional questions of it's relation to Kant's epistemological theory, to scientific and Darwinist-oriented materialism, and to Dietzgen's ethical ideas and criticism of religion. (shrink)