This shore refers to the identifiable part, that is, the "phenomenon" of things

The other shore refers to the unknown part, that is, the "thing in it" that transcends people's cognitive boundaries and exists independently. The "thing in itself" objectively exists outside the human senses. It acts on people's senses and produces feelings, but this feeling is limited. Its root lies in the principled boundary between "things themselves" and "phenomena", that is, "this shore" and "the other shore", which is an insurmountable gap in human understanding. People can only understand the phenomenon of "things in it", but can't understand "things in it" through phenomena.

In short, we can only know the phenomenon, not the essence.

Kant can be said to be an agnostic or an agnostic. The reason is that Kant not only affirmed the inevitable truth of mathematics, natural science and metaphysics, but also established a comfortable world-"things themselves" outside the phenomenal world. Phenomenal world is the manifestation of things themselves in human reason, but due to the influence of the innate framework and paradigm of human mind, knowledge is always distorted to some extent and can never be calibrated.

Kant's philosophical system is simply three kinds of criticism: pure rational criticism, practical rational criticism and judgment criticism, which roughly correspond to epistemology, ethics and aesthetics respectively. However, his criticism of judgment is rarely touched by the general philosophy major except aesthetics major.

Kant famously said, "There are two things, and the longer we think about them, the more awe and admiration they fill our hearts: the starry sky above us and the moral law in our hearts."

This sentence makes people feel very excited to read and is repeatedly discussed as an exam requirement.

In fact, the starry sky above the head and the moral law in the heart are the research objects of Kant's criticism of pure reason and practical reason respectively. Of course, the starry sky above here is not only astronomy, but the whole universe is natural.

As we mentioned before, the result of materialized world must be mechanization. Kant lived in the era of Newton's system. Newton once defined the world strictly within three laws, and Hobbes' philosophy also brought man into this system: as a rational existence, man is also mechanized, and his freedom was cancelled by strict laws. On the other hand, the skeptic Hume denied the inevitability of natural science, denied the knowability of the world, and led knowledge to people's pure association. So what Kant has to do is to affirm the inevitability of natural science and prevent it from controlling human freedom.

Kant's affirmation of natural science is entirely based on Hume, or rather, it is entirely to solve Hume's problem.

First of all, in the aspect of human understanding, Kant added an important classification: innate comprehensive judgment on the basis of Hume's analytical judgment and comprehensive judgment.

In Hume's view, propositions can only be divided into analytical propositions and comprehensive propositions. Analytical propositions are derived from logical reasoning, so they are innate, and comprehensive propositions are proved by experience, so they are acquired. But Kant pointed out that many propositions are comprehensive propositions, but they are obtained through innate logical analysis: for example, a mathematical proposition, 3+5=8, no matter how to analyze 3 and 5, the concept of 8 can not be obtained; There are also some basic physical propositions: for example, all objects have gravity, which is also a comprehensive proposition relying on logical analysis.

Therefore, there are some necessarily correct comprehensive propositions that depend on logical analysis, which Kant calls "innate comprehensive judgment". Kant put forward "innate comprehensive judgment" because innate comprehensive judgment broke Hume's theory that comprehensive propositions are only probability, thus providing a basis for the inevitability of comprehensive propositions such as mathematics and natural science.

In Kant's view, in order to get rid of the limitations of the previous philosophical system and completely solve the problem of cognition, we must completely get rid of a basic orientation of traditional epistemology: the mind should conform to the world, whether it is the materialistic perceptual world or the idealistic rational world. On the contrary, Kant tried to assume that the world should conform to the mind. Kant called this epistemological revolution a Copernican philosophical revolution. Assuming that the world should conform to the mind means that when the mind knows the world, it always brings its own cognitive paradigm to the outside world and always knows the world through its own way of knowing the outside world.

Kant's Copernican revolution can be said to be a major turning point in the history of philosophy. From then on, in the field of epistemology, people began to realize the function of mind on the object of cognition. It was from Kant's Copernicus Revolution that dialectics developed by leaps and bounds.

Then, when the mind knows the world, what is the cognitive paradigm it brings to the world? Kant believes that this cognitive paradigm is an intuitive form of the mind. Specifically, it is time and space. Time and space are like two lenses, through which the mind always knows the world. Because mathematics (including geometry) is based on the concept of space, the truth of mathematics is inevitable because of the innate nature of time and space.

It is precisely because of the intuitive form of the mind that the world we know is always affected, and it is an unreal world, so there is a distinction between the phenomenal world and the comfortable world. Things themselves show us it, but we are always influenced by our own minds and can't fully understand it.

Kant's epistemology is mainly to solve Hume's problem. Kant proved the inevitability of mathematics through innate time and space-but Hume also admitted the inevitability of mathematics. The most important question is how to prove the inevitability of natural science. To prove the inevitability of natural science, we must prove three concepts: self, universe and God. Of course, the concept of God is redundant, but in Kant's era when natural science was underdeveloped, God was still discussed as the reason for the existence of the universe.

First of all, how is the ego possible? When we know the world, we have unified our experience in the understanding of the mind. The unity of our experience shows the unity of self and proves the existence of self.

Second, why is the universe possible? By forming the concept of the world, our minds produce a synthesis of all the events in our experience, which is the universe.

Finally, how can God? By forming the idea of God, our minds produce the principles of all connections in the world. As the only sufficient reason for the existence of the cosmic sequence, this is God.

It is precisely because of the unity of self, universe and God that causality and natural science become inevitable. When our mind knows the world, it brings 12 congenital categories to the world. Our experience world is integrated into a whole by category, which is nature, and the laws imposed by category are the laws of nature. This is "artificial natural legislation".

When the inevitability of natural science is established, is man also mechanized? In Kant's view, this is not the case.

Kant believes that in the eyes of others, people obey the laws of nature as a phenomenon, but as a self, people are comfortable self and do not obey the laws of nature. In this way, he solved the contradiction between natural science and human freedom.

However, since the self is a comfortable self, how should good and evil be distinguished? So Kant put forward the goodwill and absolute command. Goodwill itself is good, and it is absolutely good; An absolute command is an imperative sentence without any conditions. It only tells you what to do and what not to do. Its purpose is itself.

Kant's God appeared as the spiritual concept of world unity, so the existence of God is unknowable, and whether man as a thing itself has the property of freedom is also unknowable. Therefore, in order to be a good person, three moral assumptions are needed:

1. Freedom: If a person is not free, then he has no reason to be responsible for his choice.

2. Eternal life: Perfection is hard to achieve, so people must believe that even if the efforts in this life are not enough, the soul can continue to strive to achieve the perfect goal after death.

3. God: People must believe that there is a God who punishes evil and promotes good, and he will always repay people's efforts.