Georg Wilhelm Friedrich Hegel (; ; August 27, 1770 – November 14, 1831) was a German philosopher who was a major figure in German idealism. His historicist and idealist account of reality revolutionized European philosophy and served as an important precursor to Continental philosophy, Marxism and historism. Hegel’s principal achievement was his development of absolute idealism as a means to integrate the notions of mind, nature, subject, object, psychology, the state, history, art, religion and philosophy. In particular, he developed the notion of the master–slave dialectic and the concept of as the expression of the integration (“sublation”, Aufheben), without elimination or reduction, of otherwise seemingly contradictory or opposing ideas. Examples include relationships between nature and freedom and between immanence and transcendence. He also made original and influential contributions to speculative logic, the role of history and the notions of the negative and the ethical. Hegel influenced many thinkers and writers whose own positions varied widely. Karl Barth described Hegel as a “Protestant Aquinas”, while Maurice Merleau-Ponty wrote that “All the great philosophical ideas of the past century had their beginnings in Hegel”. Michel Foucault has contended that contemporary philosophers may be “doomed to find Hegel waiting patiently at the end of whatever road [they] travel”.