Immanuel Kant presented several key philosophies in his writings, notably the concepts of categorical imperative and transcendental idealism. His ethical framework emphasizes that moral actions should be guided by universal maxims applicable to all rational beings. In his work, "Critique of Pure Reason," Kant explores the limitations of human knowledge and the relationship between experience and reality. His ideas on autonomy, morality, and the nature of existence have profoundly influenced modern philosophy, ethics, and political thought, establishing him as a cornerstone of Enlightenment discourse.