1743 – 1819
Friedrich Heinrich Jacobi (1743–1819) was a German philosopher and novelist who became a central figure in the Pantheism Controversy and a leading critic of rationalist metaphysics. He argued that speculative reason leads inevitably to nihilism or Spinozistic fatalism, and proposed immediate faith (Glaube) and feeling as the only genuine access to reality, God, and freedom. His critiques of Kant, Fichte, and Schelling shaped the contours of post-Kantian idealism.
Initiated the Pantheism Controversy (Pantheismusstreit) by accusing Lessing of Spinozism, forcing a public reckoning with rationalism and determinism
Developed the doctrine of immediate knowledge (unmittelbares Wissen) and Glaube as an alternative epistemic foundation to discursive reason
Introduced the term 'nihilism' into philosophical discourse as the necessary endpoint of pure rationalism
Produced sustained critiques of Kant's critical philosophy, particularly regarding the thing-in-itself and transcendental idealism
Influenced Kierkegaard, Hamann, and existentialist thinkers through his emphasis on faith, individuality, and the limits of systematic philosophy