Following an initial section, in which the relation of materialism to positivism and agnosticism is discussed, and the latter views criticized, a formal definition of dialectical materialism is given. Materialism is contrasted to idealism and dualism. Dialectics is contrasted to metaphysics. Some additional assumptions, usually included in dialectics, such as the interpenetrating character of the levels of science, and rationalism, are listed. In a section devoted to the relation between matter and spirit, the foundations of materialist ethics are laid by (...) stating the humanist axiom of purpose. In the last section, historical materialism is defined, and some reasons for the occasional entanglement of scientific, philosophical, and political controversies are discussed. (shrink)