Human beings are part of matter, as is consciousness, but exist in conflict with it. That conflict is conducted through production, which discloses human kind to itself. Dialectical materialism shows that people make history not in order to unfold some concept or destiny within them, but in order to satisfy their needs. What these needs are and how they are satisfied are determined by the level of the productive forces. As the level of the productive forces changes so social relations change.
Idealism sees economic relations as a function of human nature.
Dialectical materialism sees economic relations as a function of the level of productive forces. Human nature is determined by the interaction of the productive forces and objective nature. Dialectical materialism states that a market economy conforms with a given level of productive forces. As these forces develop so they will conflict with the market form and this economy will be in conflict with human nature. Marx and Engels demonstrated that society develops in accordance with certain laws again whether people know of their existence or not.