If intuition has no concept, it is blind intuition. According to Kant's understanding, it is empirical intuition, not pure intuition. Pure intuition must contain concepts. If thought has no content, it is empty, and intuition without concepts is blind. This idea is mentioned in the second part of his Critique of Pure Reason, the theory of transcendental logic.
Therefore, he further pointed out that the form produced by such intuition is the sensory form.
Therefore, my intuition can only be preceded by the reality of the object and become innate knowledge in one way, that is, it only contains the sensory form, which in my subjectivity is preceded by all the impressions of reality that I am infected with by the object
So, innate intuition can only involve our sensory objects.
Objects are constructed through our intuition, in the form of categories or concepts. So, that's why we have the process of having concepts first and then intuition, rather than having intuition first and then concepts. Any intuition, when called pure intuition, must already contain concepts within it, otherwise it is an empirical intuition.
However, empirical intuition cannot help us understand the object, because you cannot grasp the essence of the object. This is about how pure mathematical knowledge is possible.
When it comes to the possibility of pure natural science, there are certainly many discussions behind it. There are also many questions related to mathematical knowledge, how knowledge of geometry is possible, and why his philosophy is called a priori idealism, which are explained very clearly.
I want to briefly list this point, he said:
I myself name my theory a priori idealism, but no one should confuse it with Descartes' empirical idealism or Berkeley's mystical fantasy idealism.
Because my idealism does not involve the existence of things, because in my thinking, I have never doubted it, but only involve the sensory appearance of things; Belonging to sensory representations, first and foremost are space and time. As for space and time, and thus all general phenomena, I only point out that they are neither things nor regulations of things in themselves
And it only refers to the relationship between our knowledge and cognitive ability.
This is Kant's explanation of a priori idealism. So, if we ask why Kant called his philosophy a priori idealism, this passage is very clear, and we can understand Kant's idealism. It has nothing to do with the existence of external things. He is not denying the existence of the external world, he himself said, 'I acknowledge the existence of the external world.'.
I acknowledge the existence of the world itself, but the idealism I am talking about has nothing to do with this world. What I am only discussing is our cognition. As for the relationship between our own cognitive abilities, it is only about our cognitive abilities and how to grasp the surface of this thing.
Because things are presented to me in a superficial way. Therefore, whether we humans can grasp external appearances in our innate cognitive form has become a core philosophical question. Therefore, also known as the core issue of a priori idealism, carefully reading this paragraph, I believe we can gain some understanding of how pure mathematical knowledge is possible.
Regarding the question of how pure natural science knowledge is possible, I think there is a paragraph here that I will briefly quote.
He said that things that cannot be objects of experience must be supernatural knowledge about him. Such knowledge has nothing to do with us here. We are dealing with natural knowledge, and its reality can be confirmed by experience, although it is innate and exists before all experience.
This is knowledge about pure natural science, and he also introduced it below, so the essence of nature, in this narrow sense, is the regularity of all objects of experience. And in terms of its innate recognition, it is also the inevitable regularity of all objects of experience.
What is regularity?
Here are the concepts that conform to the innate form, legitimacy and purposefulness, because the concept of purpose is discussed in moral philosophy, and there is no teleology in his discussions about nature. Only in the field of morality and practical reason can there be teleological discourse.
Next, he will discuss the question of how general metaphysics is possible.
Metaphysics not only deals with natural concepts that are always applied within experience, but also with concepts of pure reason, which can never be provided in any possible experience. Therefore, its objective reality and the authenticity of the argument cannot be proven or revealed through any experience.
And this part of metaphysics precisely constitutes the basic purpose of metaphysics, while the rest are just means.
This part is precisely aimed at pure rational concepts, therefore, general metaphysics refers to the treatment of pure rational concepts. Therefore, what it provides cannot be verified through experience, so he raises three questions.
The question he raised about the essence and characteristics of metaphysics, that is, about the application of reason to itself, and about the so-called understanding of the object, which is rational and directly conceived from some of his own concepts. So, experience is not necessary to inquire, especially if it cannot be achieved through experience.
The use of the concept of pure reason is only internal, that is, about experience, only about what experience can be said, while the concept of reason is about completeness, that is, about the unity of the set of all possible experiences. In this way, it goes beyond any established experience and becomes transcendent.
This is the question about general metaphysics, which is about the knowledge that transcends all experiential activities and becomes possibilities above experience, making experience possible. This is called general metaphysics.
How is metaphysics as a science possible?
These are all provisions made by Kant in the Introduction we are discussing, in which he has clearly expressed this idea, which is about the metaphysics of science, that is, the metaphysics of defining the limits of pure reason.
The sensory world only contains phenomena, and phenomena are not things in themselves; However, it is precisely because the object of experience is regarded as merely a recognition of phenomena that reason must acknowledge things in themselves.
Phenomena and things in themselves are both things contained within reason, and the question arises: how can reason draw a boundary between these two domains?
Reason can only achieve this understanding when it extends itself to this boundary, but do not attempt to cross this boundary, because once it crosses this boundary, it faces an empty realm where it can certainly think of the form of things, but cannot think of things themselves.
Finally, he said, in this way, the proposition we mentioned earlier still holds: 'Reason, through all its innate principles, tells us only about objects that can be experienced, and within these objects, only about what can be known in experience.'.
This is his answer to the question of how metaphysics as a science is possible. That is to say, as a metaphysics of science, it only limits the limits that our rationality can reach.
The general metaphysical discussion is about a fundamental principle that can transcend experience. As a science, metaphysics sets the boundaries and scope within which reason can be applied. Note that the experience and scope in which reason can be applied here refers to a boundary where our reason can be applied to our intellect. When we expand intellect into reason, or bring intellect into reason, understanding is reason, and reason is reason.
Intellect is formed through categories and concepts, while rationality is achieved through form and principles. Between these two, when our general metaphysics refers to, we can establish some intellectual principles that go beyond experience through a priori means.
For general metaphysics, this is an elevated concept. However, metaphysics as a science is declining in this way. Why is it like this?
Because the metaphysics of science limits the scope of intellect in a rational way, the two are bidirectional and opposite. General metaphysics is also a set of things that rationality can do; The metaphysics of science, on the other hand, limits the scope of application of intellect through rational methods.
Therefore, in between, we will find that whether it is intellect or reason, including the previously mentioned sensibility, the issue they involve is one - nature.
Because they are all facing objects in nature, which are presented to us in the form of appearances, we cannot recognize or understand the so-called things in themselves behind appearances.
We cannot recognize the 'thing in itself', but we must acknowledge its existence because it is presented to our senses in a representational way. Therefore, when we recognize that things have such representational characteristics, we must acknowledge the existence of things in themselves. You cannot deny it, but how to deal with things in themselves is not a task that can be accomplished in the process of dealing with nature.
