Dialectical materialism is a materialist theory based upon the writings of Karl Marx and Friedrich Engels that has found widespread applications in a variety of philosophical disciplines ranging from philosophy of history to philosophy of science. As a materialist philosophy, Marxist dialectics emphasizes the importance of real-world conditions and the presence of contradictions within and among social relations, such as social class, labour economics, and socioeconomic interactions. Within Marxism, a contradiction is a relationship in which two forces oppose each other, leading to mutual development.
The first law of dialectics is about “the unity and conflict of opposites”. It explains that all things are made up of opposing forces, not purely "good" nor purely "bad", but that everything contains internal contradictions at varying levels of aspects we might call "good" or "bad", depending on the conditions and perspective. An example of this unity and conflict is the negative and positive particles that make up atoms.