I finished a summary of Kant today. He's notoriously difficult, so I welcome any suggestions so that it is accurate and precise.
Immanuel Kant lived from 1724 to 1804. In his whole lifetime, he never ventured more than a hundred miles from his hometown of Königsberg, Prussia (today in Russia). Although his early writing was popular among his contemporaries, he wrote his most enduring works in later life. The Critique of Pure Reason, which he wrote in his late fifties, would become one of the most important books in the history of philosophy.
In the Preface to his book, A Prolegomena to Any Future Metaphysics (a summary of the ideas in the Critique), Kant wrote that the empiricist David Hume had woken him from his “dogmatic slumber.” Hume had shown him that empiricism could only account for the content of our thoughts, not for the shape those thoughts took in our mind. To explain the organization of our thought, the synthesis of information in our minds, Kant suggested that our minds operate within certain a priori categories like space and time or cause and effect.
Kant believed that these categories, the frameworks by which we understand the things that we sense, are “transcendental.” Although some scholars interpret Kant differently, Kant seemed to believe that the categories by which we understand the world are universally true. On the one hand, these categories come from our minds, not from the world itself. In that sense, we cannot know the world as it is in itself, we can only know the world as it appears to us, as it is organized by our minds. We cannot understand the world without using categories like time and space, cause and effect, and believing that the things we perceive have substance.
On the other hand, Kant was inclined to think these categories were, in reality, universally true, even though our minds impose them on the data of our senses. Some who have followed Kant have accepted that our minds construct reality while rejecting that those constructions are universally true.
Kant argued that our belief in several other things followed naturally from these transcendental categories, namely, our belief in God, the soul, and human freedom. We cannot be consistent with the way our reason makes sense of the world without also affirming them.
But the way Kant affirmed them flowed straight from his philosophy. For example, freedom for Kant was to act in accordance with universal reason, not the capacity to do whatever you want to do. And the moral law for him was a function of conclusions that flow directly from the categories of reason.
Kant called his understanding of ethics, the “categorical imperative.” Kant’s thinking seems to be that if something is an imperative, a “must do,” then it is “categorically” a must do. Kant believed that if something was right or wrong, then it was always right or wrong without exception.