Few philosophers have so extensively influenced thought and language as Aristotle. His conception of the universe pervades Christian theology.

Arthur Schopenhauer was the most articulate and influential pessimist in the history of human thought.

A Portuguese Jew living in Holland, Spinoza was excommunicated because of the unorthodox view he took of God.

Nietzsche condemned nearly all of the religious and philosophical thought of his day to blunt terms (e.g., God is dead).

Immanuel Kant's "transcendental" philosophy transcends the question of "what" we know to ask "how" we know it.

Jean-Paul Sartre, a French philosopher, is perhaps the best known advocate of existentialism. In this view, no external authority gives life meaning: mankind is radically free and responsible.

John Dewey was America's most influential philosopher. He wanted philosophy to rise above old tired disputes to address new, more vital questions and problems.

Plato was the first great philosopher of the West to organize and record the issues and questions that define philosophy.

For Kierkegaard, truth is a subjective reality which we must live, not something to simply consider and discuss.