Arthur Schopenhauer was a German philosopher born in 1788. He wrote many books and was also influential in shaping philosophy, psychology, and the science of music. Schopenhauer's major work is his book "The World as Will and Representation", which argues that the world is fundamentally will (i.e., the manifestation of the will to live). His other major work is "On the Fourfold Root of the Principle of Sufficient Reason," which explains his theory about how people experience reality. Schopenhauer's core idea is that there are three basic types of explanations: The first type of explanation is a metaphysical explanation. Metaphysical explanations are explanations that are purely theoretical and do not refer to anything we can physically observe or measure. The second type of explanation is an epistemological explanation. Epistemological explanations are explanations that are purely theoretical and do not require us to rely on experiences such as thoughts, feelings, or sensations in order for us to understand them. They are based on logical deductions and observations with no reference to anything outside of those deductions and observations. The third type of explanation is an empathic explanation. Empathic explanations are explanations that rely on our experiences. Empathic explanations are developed by making observations about our own thoughts and feelings then applying them to other people's thoughts and feelings.