German philosopher Immanuel Kant (1724-1804) attempted to show universal principles of thought applicable to all times and places. He is widely remembered for synthesizing two seemingly opposite philosophical views, rationalists and empiricists. Rationalists include Descartes and believe knowledge comes from some irrefutable intellect. Empiricists, like Locke, believed the mind was a blank slate. Kant claimed rational thought imposed empiricist worldly experience to create knowledge. Kant also applied this synthesis to moral questions, and he believed rationality is the source of morality.