Aenesidemus is a German book published anonymously by Professor Gottlob Ernst Schulze of Helmstedt in 1792. Schulze attempted to refute the principles that Karl Leonhard Reinhold established in support of Immanuel Kant's Critique of Pure Reason (1781). The title is a reference to Aenesidemus, an ancient Greek Pyrrhonist philosopher. Its complete title, in English translation, was Aenesidemus or Concerning the Foundations of the Philosophy of the Elements Issued by Professor Reinhold in Jena Together with a Defense of Skepticism against the Pretensions of the Critique of Reason (German: Aenesidemus oder über die Fundamente der von dem Herrn Professor Reinhold in Jena gelieferten Elementar-Philosophie. Nebst einer Vertheidigung des Skepticismus gegen die Anmassungen der Vernunftkritik).