Immanuel Kant

Immanuel Kant (1724–1804) is the most influential thinker in modern western philosophy. 

The central doctrine of Kant’s theoretical philosophy is what he calls “transcendental idealism.”  This is, roughly, the view that there is a sharp distinction between things as they appear to us and things as they really are (in themselves). It is controversial what that distinction consists in or even how to characterize it, but it is clear that Kant wants to deny that things-in-themselves have spatio-temporal features.  Thus they are things that we can think about (‘noumena’) but not things that appear (‘phenomena’). 

Kant argues that we can only explain our knowledge of non-trivial (‘synthetic’) necessary principles -- including the principle according to which all events have causes --  if transcendental idealism is true.  He also thinks that distinguishing between phenomena and noumena leaves room for incompatibilist freedom, God, and the immortality of the soul (at the noumenal level). 

Kant places the notion of autonomy at the center of his moral and political philosophy, and argues that specific moral obligations are based in a very general principle called the Categorical Imperative.  This principle is fundamental to practical rationality and requires that we respect the autonomy of rational agents and refuse to make arbitrary exceptions for ourselves. 

In his early years, Kant was trained in the German rationalist tradition of Christian Wolff (1679–1750) and G. W. Leibniz (1646–1716). But he was influenced by the British Empiricists like John Locke (1632–1704), Isaac Newton (1642–1727), and David Hume (1711–1776). Later, Kant characterizes his Critical philosophy as a synthesis of rationalism and empiricism. 

Kant’s massive influence is felt across the continental and analytic traditions. He is typically regarded as the forefather of German Idealism, and a key figure in the development of Existentialism, NeoKantianism (obviously), Phenomenology, Critical Theory, and even Post-Modernism. 

In the analytic tradition, Kant’s views were in the background of many of the debates in 20th-century epistemology and philosophy of mind. Kantian moral philosophy is one of the main positions in contemporary ethics, and Kantian political philosophy dominated most of the discussion in 20th and early 21st century political philosophy. Kant’s views about aesthetic judgment are central to many developments in the philosophy of art and art criticism. Kant is not a major figure in contemporary analytic metaphysics, however.

The three Critiques are the central texts for Kant’s “critical system”: Critique of Pure Reason (1781/1787), Critique of Practical Reason (1788), Critique of Power of Judgment (1790). His Groundwork for the Metaphysics of Morals (1785) is among the most influential works in modern ethics. Other major works include Prolegomena to Any Future Metaphysics (1783), Metaphysical Foundations of Natural Science (1786), Religion within the Boundaries of Mere Reason (1793), Metaphysics of Morals (1797), and Anthropology from a Pragmatic Point of View (1798).