Nikolay Milkov. The Historical Achievement of Kant’s Critique of Pure Reason

1. Opening

Some fifteen years ago Hermann Schmitz asked the question ‘What did Kant really want?’ (Was wollte Kant?) His answer was: in his critical philosophy Kant wanted to theoretically ground the spontaneity of Reason [11, 365].

In this paper we will see that Hermann Schmitz’s answer to his question is correct. Indeed, in CPR Kant wanted to secure the spontaneity of reason. Schmitz’s book book, however, did not specify the theoretical resources with which he made this. Our task here will be to fill this gap.

More precisely, we are going to show that according to Kant, the spontaneity of pure reason is only secured if it is accepted that it recurrently examines the world. Further, we shall show that this is the old Plato’s idea of peirastic dialectics—of an examination of any suggested argument or theory, but also of facts and events under consideration—that Kant revived for good. So far, this interpretation was mentioned in the literature only cursorily and only in relation to the transcendental dialectics [1, 98–9n. 179].

The problem of this paper can be also articulated with help of this question: What is the real achievement of CPR as seen from bird-eye view—from the perspective of the 2500 years of history of Western philosophy? Our concern will be what Kant really revolutionised in philosophy; what were the intuitions, understandings and theories that he radically changed in it?

2. The Great Bifurcation of Philosophy1

It took place in the antiquity—in the works of Plato and Aristotle. Roughly, it was a bifurcation between applied philosophy and logical philosophy. At the beginning, Plato conceived philosophy as peirastic: as an examination of arguments, theories and facts. Incidentally, that is why he defined philosophy as a search for wisdom. Soon, however, he stared to look for some rigorous, formal discipline that can do this job with more confidence. Plato found it in the Theory of Forms, the Forms being supposed to be the objects of this autonomous discipline. This was the first attempt to systematise peirastic.

This task was carried out further by Aristotle. First, he combined the discipline of truth-searching (peirastic) with the Theory of Forms into a Theory of General Kinds. The result of this blending is to be seen in his Categories. The next step was the discovery of syllogism. That discovery was made by reducing the Theory of Forms—central to both Plato and to his Categories—and of the method of division (the analysis) to a new discipline. The novelty was that whereas the method of division accepted that the middle term is universal, syllogistic claimed that the middle term must be inferior to the first and the third one. Of course, syllogistic had not the heuristic power of peirastic; in compensation, it was much more rigorous.

This move had two important results: (1) Ontology became much more formal than before. More precisely, the investigation of Forms was replaced in it by investigation of the being qua being, the task of which was to describe the necessary principles of all sciences. (2) The new science of logical forms radically diminished the role of mathematical knowledge. This was only changed in the Enlightenment when Vietae and Descartes rediscovered analysis and developed it further. This process gone hand in hand with the refreshment of the old Plato peirastic dialectics (in the works of Hume, for example), despite the fact that scarcely anyone recognised it as such.

3. Kant’s Rediscovery of Dialectics

Kant was the greatest synopticist in philosophy. In his masterpiece, CPR, he deduced all a priori concepts from one single principle, and in one system. His synopticism, however, was not only logical; it was historical as well. Indeed, it was often being claimed that CPR was an attempt to put into one empiricism and rationalism. In contrast, we put stress on another side of Kant’s historical synopticism: he successfully combined into one the just discussed two philosophical traditions that were advanced apart for more than 2000 years: peirastic dialectics and philosophical logic.

Apparently, this step of Kant was prompted by the published in 1765 of Nouveaux Essais of Leibniz [15, 234]. Leibniz’s point was that the ‘new philosophers’—Descartes and Locke—‘have carried the reform too far’. Instead, he pleaded ‘to rehabilitate the old philosophy and restore the all but banished substantial forms’ [7, 11]. Kant followed this advice of Leibniz closely.

Toward the end of the 1760s he was a brilliant analyst. Indeed, when in 1763 the Berlin Academy of Science in Berlin organised a philosophic competition asking ‘Are the metaphysical truths at all open for the clear proofs of geometry?’, he won the second price (the first price won Moses Mendelson [3, 26 f.].After Kant read Leibniz’ Nouveaux Essais, however, he turned back to the Greeks. Indeed, in contrast to Leibniz, he did not remained by the Aristotelian substantial forms but revived a long forgotten philosophical outfield—the peirastic dialectics. We have already noted that dialectic was discovered by Plato and developed further, but in the same time made harmless, by Aristotle. In the Middle Ages it was extensively discussed, but often misinterpreted. After the analytical revolution of Descartes and Locke, it was totally forgotten. Not in Germany, however. It was preserved there in the seventeenth century—in Königsberg even in the eighteenth century [15, 241]. That is where Kant picked it out from.

4. A Short History of CPR

Historically, Kant’s masterpiece was composed in three steps.

(1) 1765–69. His first step was the discussion of the antinomies. Indeed, today it is widely accepted that ‘the problems of antinomity were developed prior to . . . Kant’s transcendental philosophy’ [12, 398]. What is more, exactly the antinomy of the pure reason helped Kant to ‘wake up from the dogmatic slumber’.2 Our guess is that his work on the antinomies in 1765–9 made Kant to go back to the technique of peirastic dialectic.

(2) 1769. Kant’s discovery from 1769 was nothing but realising of the subjectivity of space and time as a priori forms of the sensitive intuition [12, 393]. Now, our guess is that Kant found a dialectical solution to the antithetical problem when working on the subjectivity of space and time: he first made use of peirastic dialectics in the transcendental aesthetic (see the next section 5), and then resolved the antinomies in a dialectical way.

(3) 1769–80. Finally came the task of elaborating his new science (why it was new we shall see in section 7): the transcendental deduction of the categories. This task was accomplished slowly and in very hard work which, in a sense, remained unfinished (see [9, 169]). For it Kant himself has said in Prolegomena that ‘this deduction was the most difficult thing that was ever made in metaphysics’.

5. Epistemological Peirastic

Our main thesis in this paper is that in CPR Kant managed to transform the idea of examining dialectic into the idea of origin-testing activity of human mind. He thus substantiated the understanding that ‘knowledge is an activity, not a state, of the mind’ [17, 323]. On this understanding, the subject has a highest grade of creativity—of free action.

Now the origin-testing of our knowledge is realised in three forms.

(1) Intuition. Our perception (intuition) is accomplished in combining noumena and forms. Indeed, every judgement of perception tests the matter and choices out of its multiplicity some elements that it orders in a certain form (pattern).

(2) Experience. Kant claims that our experience is not merely a calculation. This means that the mere assimilation of the data of experience is not enough in order to receive new knowledge. By perceiving single individuals, we ipso facto penetrate ‘to [the] empirical or experimental conditions of their application’ ([13, 16] my italics; see also [13, 78]). These formal conditions—conditions of object’s pertaining to a certain kind, conditions of their identity, etc.—form a part of the unified objective world.

(3) Understanding. The ideas of pure reason don’t refer to objects; rather, they strive to make reason complete, this completeness being secured by principles. The need of principles of human understanding is a consequence of the discursive nature of the latter, which requires from us to ascribe a subject to every predicate, and to this subject a subject again, and so on ad infinitum [8, 333].

According also to the ordinary usage, the principles are polices for acting, including cognitive acting. Something similar goes for ideas. Truly, the peculiarity of Plato’s ideas, for example, is that they both have their own being, and in the same time are related to reality. This is exactly what Kant’s ideas are. They are formulas for testing, examining reality, according to a supreme principle.

Evidently, ideas are not constitutive but rather regulative. So they do not directly refer to objects. The great mistake of the pre-critical metaphysics is that it followed the reason, who often gives way to the inclination to use ideas as if they do directly refer to objects. An example: we neither have an experience with infinite, nor with finite space/time. These are only ideas of adding/dividing phenomena which we often treat as directly referring to objects.

6. Judgement—The Uniting Element of Pure Reason

The examining function of human reason, that we just have followed on three levels, is its unifying element. In the formal (general) logic it is called judgement. The centrality of judgement makes Kant to define reason as ‘the ability to judge’ [6, A69/B91].

Indeed, the judgement is a necessary element of any form of examining:

  • In perception (in the synthesis of apperception) the judgement unifies the multiplicity of experience into one notion;

  • In thinking (the synthesis of apprehension) it connects notions to concepts;

  • In understanding it puts the multiplicity of the concept under ideas.

That explains why both the deduction of the categories and the exposition of the antinomies of reason are based on the conventional classification of judgements in formal logic. The difference is only that while the sources of the categories are the four logical functions of the judgement of the pure reason, the sources of the ideas are sough in the three functions of the inference of understanding [8, 330].

This function of judgement is the same both in the synthesis of the apprehension, i.e. in our ability to imagine, as well as in the synthesis of apperception, i.e. in our ability to judge. However, while the judgement used in our ability to imagine is a blind function of the soul [6, A78, B103], in our ability to judge it requires a talent that cannot be learned but exercised [6, A133/ B172].

7. Kant’s Transcendental Idealism as a New Logic

Kant’s project for transcendental idealism was nothing but an advancement of a new formal discipline in philosophy—of a new logic. More precisely, after his turn of 1769, Kant made something similar to what Aristotle did in regard to Plato’s dialectic: He as if tamed it in the net of logic, inventing in this way a new formal discipline that he called transcendental idealism.

This point is manifested quite well in the fact that both Aristotle and Kant claimed to have discovered a totally new science. So Aristotle was adamant that he was first in writing down the science of syllogistic: I had no predecessors, said he in Soph.El 184b1–3. Similarly, Kant uses to repeat: ‘This [his transcendental idealism] is a totally new science of which nobody has ever thought of.’ [8, 262] In history of philosophy this claim of Aristotle–Kant is unique.

Kant’s new science is, above all, formal. First, similarly to Aristotle’s syllogistic, transcendental idealism claimed that all parts of our pure knowledge are organically connected with one another. They are deducible from one principle (from the judgement) in a transcendental deduction of categories [4, 79]. Secondly, similarly to Aristotle’s syllogistic, its function was to advance a strict chain of inferring—not to support truth-discoveries. Indeed, Kant’s transcendental idealism was restrictive, not heuristic: what was heuristic was tucked into what is formal.

Specifically, Kant’s new logic was a synthesis between formal logic and peirastic. This was a new, ‘vertical’ kind of logic which, besides intuitions and notions, also included in itself free will and action—the practice of judging. In other words, the new logic was a sublation of the conventional formal logic—inasmuch as it suggested a formula for recurrent search of something that is basic to perception and experience.

In a way, the transcendental idealism was developed inparallel to Aristotle’s syllogistic and so seconded it. Incidentally, Kant was explicit that his table of concepts corresponds to the [Aristotelian, in principle] table of judgements. Indeed, the concepts are nothing but judgements, but applied to intuition [8, 302].

Another characteristic of Kant’s new logic was that it set out a program for content logic. More precisely, the content is involved in it through the procedure of examining the matter. Putting this in Wittgensteinaian idiom, we can say that while Aristotle’s logic consisted only of rules, the new logic of Kant added to the rules the method of their application.

8. The Aftermath

The introduction of Kant’s new logic had consequences that pointed at quite different directions.

(1) Kant’s new logic made conventional logic much more formal. This development was carried out further by Johann Friedrich Herbart. Later it was criticised by the neo-Aristotelians of the nineteenth century Adolf Trendelenburg and his pupil Franz Brentano.

(2) The advance of new logic had as an effect the establishing of the Kathederphilosophie in the German universities: this was the institutional effect of accepting the new method of doing philosophy. So within the next 25 years after the publishing of CPR, the great men contemplating the world sub specie aeternitatis vanished from Germany without a trace.3 Incidentally, this process was related to what occurred after the victory of analytical philosophy in England in the late 1920s and early 1930s.

(3) The introduction of the new logic in philosophy had, however, another effect on philosophy which was related to that of the introduction of the logical analysis in the twentieth century: ‘[the] subsequent unavoidable dryness, and scholastic precision’ [8, 262]. This was the result of the requirement that philosophy must develop not spontaneously but under the control of the logical schemes. Indeed, Kant was adamant that the critical reason ‘keeps common reason in check and prevents it from speculating’ [8,259]. Thus, it is something like an intellectual police [6, B xxv] which must keep philosophers away from speculation. (The metaphor of intellectual police is also used in [8,§ 57]).

In a similar way, the intellectuals of the twentieth century, foreign to the analytic tradition in philosophy, understood its function, when confronted with it, as that of ‘philosophical police’. This was also the impression of Albert Einstein when he read something of Russell’s writings on epistemology [2, 281].

For our investigation it is interesting to point out that similar effects had also Aristotle’s attack on Plato’s dialectic. Indeed, it ‘may usefully be compared with the attempt of the twentieth-century positivists to free science from metaphysics. Aristotle rejects the pretensions of a non-empirical discipline claiming to be a science and to prescribe to the genuine empirical sciences.’ [5, 147]

(4) The theoretical effect of introducing the new logic in philosophy was the slow but steady increase of its influence. This finished with the victory of the analytic philosophy over continental philosophy in the second half of the twentieth century.

9. Kant’s New Logic as Philosophical Logic

Kant’s new logic from CPR was developed in the next two centuries in the form of philosophical logic. It was first called so by Trendelenburg in 1840, and advanced further by the neo-Kantians from the second half of the nineteenth century. It received a full-fledged form in analytic philosophy.

In this connection, it is of importance to mention that philosophical logic had a peculiar kind of progress, different from that of both peirastic dialectics and formal logic: Its progress was closer to the progress of rules-of-a-game than to a progress in style. This explains its rather slow advancement.

This fact explains why Bradley, who, ‘unlike many of his Oxford contemporaries . . . had no high opinion [of German philosophy]’ [14, 7], nonetheless accepted practically all discoveries made in philosophical logic of the German neo-Kantians Lotze, Erdmann, Sigwart. It also explains the otherwise mysterious fact that Bradley, the Hegelian, strongly influenced Moore and Russell, the atomists: he influenced them through some theses of his (Kantian, in spirit) philosophical logic. Another typical example is the fight against psychologism in logic in the last decades of the nineteenth century. In fact, it was nothing but a fight for the assimilation of the new, philosophical logic.

The new, philosophical logic had as a result a further clarification of the conceptual scheme of the pure knowledge, as well as of the whole of philosophy. More precisely, it was developed as an extensive investigation of the being qua being. The latter was already treated by Plato, and, as mentioned, was developed in full (after the discovery of syllogistic) by Aristotle. Kant’s merit was that he was the first to articulate it in a clear-cut form. But how did he made this?

The first example of the new (philosophical) logic was suggested by Hume. He, in particular, made the ontological discovery that causal connections have not a necessary character. An implication of this discovery was the requirement every philosophical theory to be tested is it free from accepting necessary causes.

Picking up where Hume left off, Kant made this requirement of testing philosophical theories and statements systematic (cf. [8, 257–60]). Indeed, first declared task of CPR was to suggest a comprehensive philosophical theory, deduced from one principle, which to serve as an a priori canon for examining pure reason. This characteristic of the new, philosophical logic can be also expressed this way: ‘[Kant] made all material questions dependent on solving methodological problems’ [16, 26]. Indeed, Kant was adamant that CPR ‘is a treatise on the method’ [6, Bxxii]. Further, Kant insisted that this is a specific philosophical method which is not merely an application of the methods of mathematics on philosophy, as it was accepted by Plato–Descartes–Leibniz–Hume. In fact, this point of Kant was a revival of an old Aristotelian belief. This was, incidentally, a severe blow against the analytism in philosophy. Ironically, it was partly neutralised with the emergence of the analytic philosophy which, besides components of analysis, also embraced a Kantian, in spirit, philosophical logic.


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1 The remarks in this section are based on [9, 44–56].

2 See Kant’s letter to Garve from Sept. 21, 1798 [7, 265–266].

3 As Hegel deplores in Sc.Log. § 26.

This article was firstly published in collected articles “Kant zwischen West und Ost” (2005):

Milkov, Nikolay. The Historical Achievement of Kant’s Critique of Pure Reason// Kant zwischen West und Ost. Zum Gedenken an Kants 200. Todestag und 280. Geburtstag. Hrsg. Von Prof. Dr. Wladimir Bryuschinkin. Bd.2. Kaliningrad, 2005. P. 200- 209.