Philosophy became fully modern in the nineteenth century in the sense that nineteenth century philosophical schools of thought and methods of analysis are still practiced by professional philosophers today. Modern philosophy is characterized by empiricism on the one side and a reaction against empiricism on the other. It consists of a series of inquiries that continue to be used as classic foundations for contemporary thinkers, who build upon it still. Its primary founders flourished in the nineteenth and early twentieth centuries, and they set the stage with problems that gave rise to existentialism and phenomenology, or continental philosophy; American philosophy, or pragmatism; Anglo-American analytic philosophy, including what is now known as “philosophy of science;” and the new philosophies of post-structuralism, post-modernism, feminism, and race and post-colonialism.

The hallmark of modern philosophy has been a constantly renewed awareness of other fields as philosophically interesting, such as social criticism, political science, physical science, psychology, mathematics, logic, and literature, and new understandings of the human subject as both a generator and subject matter of philosophical thought.