The purpose of the dialectic method of reasoning is resolution of disagreement through rational discussion, and, ultimately, the search for truth.One way to proceed—the Socratic method—is to show that a given hypothesis (with other admissions) leads to a contradiction; thus, forcing the withdrawal of the hypothesis as a candidate for truth (see reductio ad absurdum). Another dialectical resolution of disagreement is by denying a presupposition of the contending thesis and antithesis; thereby, proceeding to sublation (transcendence) to synthesis, a third thesis.
- Everything is transient and finite, existing in the medium of time.
- Everything is composed of contradictions (opposing forces).
- Gradual changes lead to crises, turning points when one force overcomes its opponent force (quantitative change leads to qualitative change).
- Change is helical (spiral), not circular (negation of the negation).
The concept of dialectic (as a unity of opposites) existed in the philosophy of Heraclitus of Ephesus, who proposed that everything is in constant change, as a result of inner strife and opposition. Hence, the history of the dialectical method is the history of philosophy.