It’s the birthday of Enlightenment philosopher Immanuel Kant (books by this author), born in Königsberg, Prussia in 1724. His father was a saddle maker. He studied theology, physics, mathematics, and philosophy at university, and worked for a time as a private tutor; he made very little money, but it gave him plenty of time for his own work. He lectured at the University of Königsberg for 15 years until he was eventually given a tenured position as professor of logic and metaphysics in 1770. Though he enjoyed hearing travel stories, he never ventured more than 50 miles from his hometown, believing that travel was not necessary to solve the problems of philosophy.
In his most influential work, The Critique of Pure Reason (1781), he argued against Empiricism, which held that the mind was a blank slate to be filled with observations of the physical world, and Rationalism, which held that it was possible to experience the world objectively without the interference of the mind; instead, he synthesized the two schools of thought, added that the conscious mind must process and organize our perceptions, and made a distinction between the natural world as we observe it and the natural world as it really is. He viewed morality as something that arises from human reason, and maintained that an action’s morality is determined not by the outcome of the action, but by the motive behind it. He is also famous for his single moral obligation, the “Categorical Imperative”: namely, that we should judge our actions by whether or not we would want everyone else to act the same way.
He wrote, “Two things fill the mind with ever-increasing wonder and awe […] the starry heavens above me and the moral law within me.”