Johann Gottlieb Fichte
Karl Leonhard Reinhold (26 October 1757 – 10 April 1823) was an Austrian philosopher who helped to popularise the work of Immanuel Kant in the late 18th century. His "elementary philosophy" ("Elementarphilosophie") also influenced German idealism, notably Johann Gottlieb Fichte, as a critical system grounded in a fundamental first principle.