Analysis of test questions: The Enlightenment flaunted freedom and rationality. The "moral law in mind" is freedom and rationality. The starry sky above my head and the moral law in my mind represent two major themes of Kant's philosophy, namely, nature and freedom, the world of feeling and the world of reason, which are closely related to our sense of existence. Nature starts from my position in the external sensory world, and extends my connection in it to the infinite space of many worlds and galaxy layers, as well as the infinite time reflecting their cyclic movement, generation and continuation. Every time I think about it, I don't know how small I am. We all have some awe of this vast and almost indescribable universe. Freedom is different. It starts with my invisible self and personality and presents me in a real and infinite rational world. Although this is a world that only reason can think about, I find that my connection with this world is not purely accidental, but universal and inevitable. I can connect with all those tangible worlds through this ontological world. Obviously, this rational world makes us even more amazed. Although these two worlds are closely related to my existence, they have completely different meanings to me. As far as the tangible feeling world is concerned, as a member of nature, like all other natural beings, we are just a link in the endless causal chain of nature. In the vast universe, our home-the earth-is just a drop in the ocean, a trivial dust, and we ourselves are insignificant creatures living on this dust. We don't know why we are given an extremely short life, and we don't know when and where we will give up life and rejoin the eternal material cycle of nature. In this sense, man is only a limited natural existence. Even if he has cognitive ability, he can know the natural laws of the universe, even if this natural law is endowed by his intellectuality, it will not help, because he is a natural being anyway, and his position is no different from that of a stone or a tree. However, as far as the intangible knowledge world is concerned, the situation has changed. Because this extrasensory world shows us that man is not only a natural existence, but also a rational existence, and as a member of the rational world, he has infinitely improved his position and value as a personality and rationality. In personality, the self-discipline of moral law presents a certain way of life independent of animals and even the whole sensory world. It shows that human beings, as rational beings, have real freedom to legislate for themselves, and their existence is completely determined by themselves. When he acts according to the moral law, he gets rid of the heteronomy status as a "thing" and has the freedom and dignity beyond all natural existence and without natural restrictions. Of course, it is impossible for us to confirm the reality of this rational world from the perspective of understanding, but in the field of practice, it can at least be derived from the "supreme goodness" derived from moral laws, and this ultimate goal is by no means limited to the conditions and boundaries of this secular life, which makes my existence point to eternity.