The question of how you know what you know is far from trivial. #epistemology is the branch of #philosophy dealing with this question. Arthur #schopenhauer (1788–1860) came up with a unique answer that has influenced later thinkers. In his early years, Schopenhauer had declared allegiance to the epistemological doctrines of #immanuelkant (1724-1804). I am referring to the theory of concept formation presented by Kant in his book “Critique of pure reason” (1781). In 1808, Schopenhauer published his PhD dissertation “On the fourfold root of the principle of sufficient reason,” stating his overall allegiance to Kant’s epistemology. However, there is one point where he had not endorsed Kant. On that point, Schopenhauer claimed that he was improving Kant’s epistemology, although in reality, he was nullifying one of the pillars of Kant’s “Critique of pure reason.” What was the point of discord between Schopenhauer and Kant? What drove Schopenhauer to build a new philosophical system almost from scratch? Schopenhauer diverged from Kant on the nature of “things-in-themselves” or “noumena.” Those Kantian terms refer to the ultimate #reality behind appearances. Kant had employed the word “noumena” to refer to truths, ideas, concepts and principles that aren’t directly derived from perception. For instance, Kant had argued that #ethical truths cannot be derived from perception. In his “Critique of pure reason,” Kant had categorised ethical principles as “noumena” outside of human knowledge. In “Critique of Practical Reason” (1788), Kant had softened his position. This time, he had theorised that ethical #principles could be inferred from “universal imperatives,” but his formula for arriving at “universal imperatives” is primarily subjective. In contrast, Schopenhauer affirmed that humans can acquire knowledge in all areas, provided that they take the will (“life force”) into account. Here is the link to the original article: https://johnvespasian.com/schopenhauer-and-knowledge/