Kant’s Critique of Pure Reason: Limits of Knowledge
Metaphysics and Science. Kant believed that for a trial to be considered scientific, it must meet two requisites: to increase our knowledge and to have necessary and universal validity. Its validity cannot come from experience, as this is changing and provides only probable generalizations. Thus, scientific judgments must be synthetic a priori, in which the predicate is not included in the subject of the sentence, as occurs in analytic judgments, and they provide hitherto unknown connections. This connection should not be based on experience, but regardless of experience, a priori.
Mathematics treats space and time. Geometry analyzes the properties of space, arithmetic that of time. Both space and time are the conditions under which every phenomenon has to occur. The properties of space and time are transmitted to any phenomenon that can occur in them. As a consequence of all this, all knowledge of mathematics must be universal and necessary, since all phenomena must necessarily exist in space and time. These synthetic judgments are possible a priori in mathematics. Synthetic judgments a priori are possible in the natural sciences because they are based on the categories. Understanding requires the purpose of understanding the transcendental forms or categories. Consequently, we can never know objects as they are in themselves, that is, as noumena (what I know, God, soul, and world), but only as presented to us through these transcendental structures of feeling and understanding, that is, as phenomena.
Kant reminds us of the dogmatic rationalist metaphysics of Wolff. Metaphysics is purely rational knowledge, which dispenses with sensitive data. Metaphysics is the attempt to free our notions of the limitations of mere observation.
It is impossible to have knowledge of things in themselves, and specifically the soul, the whole world, and God, even if those ideas enable us to unify our understanding of phenomena. We cannot know them because we have no intuition of them. We only have the intuition that lets us know the phenomena of nature.
Metaphysics is reduced to a simple analysis of concepts, which does not reach reality. Metaphysics as a science is impossible, although there is a natural tendency to apply the inevitable categories of understanding beyond sensitivity, trying to reach the absolute knowledge that we cannot obtain.
Metaphysics still has a critical role or regulatory dogmatism that seeks to eliminate, to safeguard the claims of morality and religion, and to avoid speculation by pointing out the limits of scientific knowledge. Metaphysical knowledge of reality, purely rational knowledge, is not possible, but we can know the source of metaphysical error. Positively, it drives the human being to continue investigating, trying to find greater unity and coherence of all knowledge.
The Fundamental Problem of the Critique of Pure Reason
The fundamental problem of the Critique of Pure Reason is to determine the limits of knowledge. It is an epistemological task, made repeatedly by Kant as a meta-question: Kant is not interested in knowing what we know of reality, but what are the conditions under which we know reality (transcendental approach). The very notion of reality (noumenon) is investigated and dissolved by Kant. This epistemological approach leads Kant to place the subject in the center of the knowledge process, in what has been called the “Copernican revolution”, which puts the subject as an active constructor of the concepts and judgments that express genuine scientific knowledge.
Kant’s Acumen and Newtonian Physics
Kant’s acumen is a model of the true knowledge of the laws of Newtonian physics. The system of the world described by Isaac Newton in the eighteenth century represented a peak in the rational knowledge of nature. It is remarkable that Kant does not question the truth of scientific statements: he takes them as a model for all universal truth, and what the Critique of Pure Reason seeks to clarify is whether we can and how can we ensure in metaphysical judgments a measure of truth like that of scientific propositions.
Is Metaphysics Possible as a Science?
On this basis, we can now formulate one of the main objectives of the CRP: Is metaphysics possible as a science? To answer this question, we must first determine the conditions that make scientific statements true, and secondly, adequately define the concept of metaphysics, and position metaphysical models proposed by previous philosophers.
Kant’s Identification of Knowledge with “True Knowledge”
Kant identifies knowledge with “true knowledge.” For a requirement of logical consistency, it is impossible for knowledge to be false. In the event that man reaches scientific knowledge of the world, such knowledge will merit such a description only if it meets certain criteria of rationality. These criteria are universality and necessity, as explained in another article. As we see, human rationality itself gives knowledge the character of “truth.” A “false knowledge” (which fails to fulfill any of these features), if this expression had any sense, would be true in an unauthorized operation or illegitimate use of reason.
Types of Judgments that Express Knowledge
If the characteristics of true knowledge are universality and necessity, the question now is how these characteristics are expressed. Kant responds to this by a rigid structure of the types of judgments that express knowledge. All knowledge is expressed in judgments, which are, remember, the result of the work of reason or the authority to judge (link subjects with predicates). Judgments are statements that may be true or false. From an analysis of judgments, Kant determines their well-known dual purpose: first, judgments are classified into a priori and a posteriori. Secondly, into analytical and synthetic.
Analytic and Synthetic Judgments
Analytic judgments are a model of logical truth. Although at times they may be required initials of any scientific discipline, for example in the definition of primitive terms, they alone are not sufficient to expand the field of knowledge, as they do not contain empirical data. These are tautological, or merely clarifying or explanatory trials (the predicate clarifies or explains the content of the subject, but does not extend it). Rationalism, basing its idea of knowledge and innate ideas on concepts voluntarily devoid of empirical content, uses and abuses the analytical criterion of truth, thus falling into dogmatic and speculative positions.
Synthetic judgments, in turn, broaden the field of experience, but alone are not able to give it the necessity and universality required by the Kantian criterion of truth. Synthetic judgments produce contingent knowledge, as Hume and empiricism had shown, thus resulting in skepticism. For Kant, this knowledge is based on mere empirical generalizations and should be supplemented in some way to be accepted as a model of scientific knowledge.
A Priori and A Posteriori Judgments
The classification of analytic and synthetic judgments, therefore, does not solve the issue that Kant investigates. Kant proposes to introduce a new distinction between types of trial. This new classification criterion uses a trial relationship with experience. According to her, trials can be classified into a priori and a posteriori.
A judgment is a posteriori if its truth can only be established after experience. That is, if it can be corroborated or falsified by it. “The table is green” is a subsequent trial, as its contents go to the experience required to be proven.
A judgment is a priori if its truth does not depend on experience, that is, it is prior to and independent of it. A priori judgments are an expression of Pure Reason, that is, of the innate capacities of reason itself before any empirical operation.
Synthetic Judgments A Priori
The combination of the two previous classification criteria led to the idea of a special type of view that adds to its ability to expand our knowledge (synthetic) the ability to make this expansion a priori, that is, as a result of the operations of the understanding of the subject. Synthetic judgments a priori are the model of knowledge sought by Kant. In both synthetic, a breakthrough in knowledge is produced. As a priori, the content expressed necessity and universality, characteristics that theoretical or pure reason lends by its own constitution. Such privileged judgments are expressed in mathematics and theoretical physics. If they were identified also in metaphysics, Kant could declare it “possible” in order to get this knowledge from the stagnation of centuries and the disrepute into which, he says, it has fallen in the eyes of his contemporaries.
But unfortunately, Kant’s opinion is not favorable. Synthetic judgments a priori cannot exist in metaphysics because in the constitution of metaphysical concepts, experience has not been taken into account: there is no experience of the soul, freedom, or God, for which trials containing these concepts can extend the scope of my knowledge of them.
Matter and Form in Judgments
To understand how Kant argues, we must now deal with how he builds Reason trials. According to Kant, any trial is a composite of matter and form. Matter is the empirical content of the trial, and the form is the way in which Reason structurally supports, organizes, and builds the trial. In sensitivity, the impressions are matter, and Space and Time are how sensitive. In their synthesis, insights or phenomena arise. In Understanding, the matter is the phenomenon created by sensitivity, and how are the categories. The synthesis of matter and form, that is, between experience and a priori categories, emerge concepts and their trials. Intuitions without concepts are blind. Concepts without intuitions, empty.
Understanding and the Categories
As we say, the faculty of Reason responsible for building the concepts is Understanding. This takes the phenomena or intuitions that pays the sensitivity, the ability to receive sense impressions from outside, and is organized under Space and Time. Sensitivity is built, then the phenomena. And Understanding, the synthesis occurs between them and the categories, leading to concepts. The Categories, or pure forms of understanding, are twelve, organized into four groups. According to Kant, they can be explained by the logical structure of any trial.