Pragmatism, which is one of the mainstreams of the philosophy of law, became popular in the UK especially after the 18th century on the basis of utilitarianism, and in the USA and Scandinavian countries after the 19th century on the basis of realism. Books on philosophy of law and legal theory discuss these philosophies under the headings of pragmatist and realist philosophies of law, and present it basically as a continuation of the British and American philosophy. However, the roots of these legal movements, which are epistemologically experimental and sensational, ontologically realistic, and ethically utilitarian and relativist should be sought in the whole history of philosophy especially in Ancient Greek Philosophy. Thus, to show this historical background, in the article, we try to return to the history of utilitarianism, pragmatism, realism and relativism in philosophical thought. In the last part of the article, with the help of examples taken from some assessments of contemporary pragmatist and realist philosophers of law, how pragmatism respond to today's complex and interactive social reality is discussed.