There are three main approaches to relational dialectics&colon; monologic, dualistic and dialectic. Engels further explained the "materialist dialectic" in his "Dialectics of Nature" in 1883. Engels later developed a "materialist dialectic" philosophy of nature ("Dialectics of Nature", 1883). Contradictions are the core concept of relational dialectics. This is the essence of what is popularly called Hegelian dialectics. There Marx says he intends to use Hegelian dialectics but in revised form. Humanistic instruction comprised grammar, rhetoric, dialectics, arithmetic, geometry, music, and astronomy (trivium and quadrivium). This conception of dialectics derives ultimately from Heraclitus. Endogenous changes can occur in social systems and can be modelled by Marxian dialectics. There is a preliminary discussion about the distinction between logic and dialectics. Ethics plays a major role in the study of interpersonal communication, particularly relational dialectics. The human grieving process is marked by relational dialectics. Theodor W. Adorno's "Negative Dialectics". The term "logic" he reserved to mean "dialectics". Soon afterward, Losev was arrested because of his book "The Dialectics of Myth".