Kant scholarship rarely acknowledges that he grew up as a Christian of the Lutheran denomination of Prussia. In Kant's Copernican Turn, author Hilmar Lorenz explores the depth to which Kant's faith influenced his philosophy. In the preface to Critique of Pure Reason, Kant refers to his turning toward faith and incorporating belief in God and a future life into his philosophical methodology. In addition to the Critique of Pure Reason, Lorenz draws on the Doctrine of Transcendental Methodsin which Kant distinguishes between knowledge that is objectively sufficient and knowledge that is subjectively sufficient (knowledge based on faith). Influenced by David Hume's philosophy of scepticism, Kant rejects theoretical knowledge on the grounds that it can never be reasoned in a sufficiently objective manner. For Kant, all theoretical knowledge presupposes knowledge of something and therefore forever remains exposed to the basic epistemological question: How does one know what one claims to know? Kant claimed that faith alone could provide an answer to this question. Lorenz rejects the anachronistic scholarly standards of much Kant scholarship, and instead seeks to systematically proceed using Kant's end-oriented methodology. In doing so, he tries to understand Kant as he understood himself. Ultimately, the author strives to prove that this understanding is only complete and accurate when it includes the concept of free will and the other tenets of the Lutheran faith as Kant understood them.