Immanuel Kant Critique of Pure Reason

Historical Context Kant lived during the age of enlightenment The spirit of enlightenment (Aufklaerung): 1. Universalism: The thinker tried to reflect the cultural development of science and economics as new era in humanity 2. Struggle against religious worldview: Religion was seen as superstition that must be clarified by an scientific explanation of the reality. 3. The alternative Worldviews: a. Deism (England); b. Materialism (French). In Germany the enlightenment was not radical and tended to a synthesis of all contrary streams.

The Project of Kant’s Philosophy Kant’s philosophical project can be formulated in three questions: 1. What can I know? The Answer is the content of “Critique of pure Reason” [Kritik der reinen Vernunft] 2. What should I do? The Answer is the content of “Critique of practical Reason” [Kritik der praktischen Vernunft] 3. What can I hope? The Answer is the content of “Critique of Judgment” [Kritik der Urteilkraft]

Kant’s Approach to the Problem of Knowledge - Criticism Kant’s Philosophy is called “criticism”. It can be defined as a philosophy that is critical against the dogmatism. Dogmatism is a form of knowledge that is achieved without researching first the condition of possibility [die Bedingung der Moeglichkeit] of our knowledge capacity. E.g. metaphysics. Contrary to it the criticism is a form of knowledge that is achieved, after we question first the limits of our capacity to know the reality.

Proceduralism For Kant it is more interesting to know the form of our knowledge than the content of our knowledge. Therefore he focused his research on the procedure by which we get our knowledge of reality. So, his epistemology is a research on the validity of our knowledge. He wanted to know, if the mathematics, physics and metaphysics are valid as science or not. Valid as science means that they can give us a reliable knowledge that has empirical evidence.

The Main Problem of “Kritik der reinen Vernunft” Kant asks, how the synthetical judgment like “all events in the world has a cause” is possible. “all events in the world” = subject of the sentence “has a cause” = predicate of the sentence The predicate is not the analytical result of the subject, but gives us a new information (so, it is synthetic, and not analytic) However all the sentence is a priori (a priori synthetic): We needn’t to find the causes of all events in order to justify the truth of his sentence. So, Kant’s question is: How is the a priori synthetical judgment in Physics possible?

Three Levels of Knowledge Kant answers the question in that he sketches the process of our knowing activity as three levels: 1. Transcendental Aesthetics (Knowledge on the sensuous level) 2. Transcendental Analytics (Knowledge on the intellectual level) 3. Transcendental Dialectics (Knowledge on the rational level)

The Phenomenal and Noumenal According to Kant we don’t know the thing in itself (das Ding an sich). We know only the appearance of the table, for example, but the table in itself, i.e. the essential table, cannot be known. The table that we see is the combination between the result of our sensuous activity and the appearance of the object that is caused by “das Ding an sich” beyond the empirical reality. The table lies on the phenomenal field of reality The table in itself lies on the noumenal field of reality

I. On the sensuous level (Sinnlichkeit) On this level our knowledge on the table is a combination between a priori and a posteriori elements: A priori on the side of knowing subject: our senses have a priori of space and time A posteriori on the side of known object: the appearance of the table is chaotic without the a priori of the subjective side of knowledge. The a priori can be illustrated as glasses. Without then the reality outside seems blur. On this level Kant justifies Mathematics as science, because space and time are our a priori

Space as a priori “Space is not an empirical concept…the representation of space cannot be borrowed through experience from relations of external phenomena, but, on the contrary, this external experience becomes possible only by means of the representation of space” (Kant, Chritique of Pure Reason, in: Baird, p. 492)

Time as internal sense “Time is nothing but the form of the internal sense, that is, of our intuition of ourselves, and of our internal state…Time ist the formal condition, a prioru, of all phenomena whatsoever…”

II.The Intellectual Level (or Verstand) On this level our mind combines two or more separated phenomena. E.g. “The table is damage because of fire” How it combines “table” and “fire”? According to Kant our mind has a priori categories (12 categories). One of them is “causality”. So, this category constructs two or more separated phenomena in an intellectual order. Then we know why the table is damage, i.e. because of fire. On this level Kant justifies the validity of physics as science, because the causality that is central on the physics is the a priori category of our mind.

Verstand or Understanding “All judgements therefore are functions of unity among our representations, the knowledge of an object being brought about, not by an immediate representation, but by a higher one, comprehending, comprehending this and several others, so that many possible cognitions are collected into one.”

III.The Rational Level (or Vernunft) On this level our mind produces argument by combining the statements of our intellect. The a priori of our mind is the three ideas of pure reason, i.e. “world”, “soul” and “God”. The ideas are not objects of knowledge, but principles in our mind that guarantee the unity of events in the physical world (world), the psychical world (soul) and in the all thing (God). They are also not constitutive, but regulative.

Is the metaphysics possible as science? Kant answered with a no. Why? The ideas of God, world and soul are not object of knowledge, but only unifying principles of our mind. They are not empirical reality, but transcendental principles by which we unify the physical and psychical processes in a rational order. Also, the metaphysics is a form of knowledge that doesn’t reflect the reality outside our mind. In the metaphysics our mind reflects itself. Although the metaphysics is not valid as science, it is according to Kant a possible form of knowledge. It is not a science, but a form of knowledge. The metaphysical claims of God, world and soul have not ground in the empirical world. They go beyond the limits of our reason.