On Kant doing philosophy and the Peircean alternative

1 Introduction

Why and how has Kantian philosophy become so important in my philosophical inquiries? As a member of a kibbutz in Southern Israel, and after working there for many years, I asked to be given a chance to study philosophy at Tel-Aviv University, which was an interest of mine from youth. I received my wish on the condition that I do additional duties beside my studies. I studied Spinoza, Kant, and other ancient and modern philosophies, e.g., Logical Positivism, Analytic Philosophy, and more. Later on, I was sent to work at a youth organization in Boston. After some time, I was accepted to doctoral studies at Brandeis University. My good recommendations from Tel-Aviv University granted me a scholarship and a fellowship that supported me in my studies for two years, 1970–1972.

At Brandeis I met Karl Popper and, discussing philosophy with him, I discovered that he was a neo-Kantian; he acknowledged it. In 1979, I was accepted to Harvard University as a research scholar in the philosophy department where Hilary Putnam was the chair. I found out that he also was a neo-Kantian, and he too acknowledged it. I have then learned that other prominent philosophers are also neo-Kanian, including Donald Davidson from Berkeley, Jaakko Hintikka (when we met at International Wittgenstein Symposium in Kirchberg), and Nicholas Rescher of the Center for Philosophy of Science at the University of Pittsburgh, among many others.

Some of these important philosophers consider themselves Peircean Pragmatists due to their acquaintance only with Peirce’s early writings, when he was “a pure Kantist,” and not with his mature writings from 1903 to 1909. My analysis of Analytic Philosophy, Logical Positivism, Logical Empiricism, Phenomenalism, and more is based on my acquaintance with Peirce’s late writings, which began when I was a visiting scholar at Harvard and researched his unpublished manuscripts in the Houghton Library, 1979–1981. All those philosophical movements are, in different modes, neo-Kantian, lacking any theory of truth to prove our knowledge of reality. Only in his late writings did Peirce complete his anti-Kantian Copernican revolution, while he continued to accept formal logic and pure mathematics in following the Kantian formalism, which contradicts his Realist Epistemological revolution, instead of developing an Epistemic Logic that is already hidden in his semiotics (Nesher 2018).

In my work on Kant’s Transcendental epistemology, I criticized his three Critiques and showed that none of them can solve the problems that Kant endeavored to solve and he even, in a way, acknowledged it. In the first Critique Kant attempts to solve the difficulties of the Cartesian Idealism and Humean Empirism, in combining them mechanically in his own Transcendental formalism and Sensual matter without being able to bridge the gap between his formal empty concepts and the material blind objects utilizing his bizarre schematism to make possible the logical judgments as our knowledge. Yet, in his late research he admitted his failure to bridge the gap between his Transcendental pure formalism with the Sensual matter of experience, as he also told his friend Grave that this gap remains within his epistemology (Kant 1993 [1798]: 257). Moreover, in this Critique, Kant admitted that he does not have any way to make our science true even to our phenomenal experience. In the second Critique, he endeavored to make his Practical Reason of the a priori pure fact of formal morality into free moral conduct to materialize his ideal commonwealth of ends, as Spinoza explains the human ethical freedom, but Kant could not bridge this gap. In his third Critique, Kant attempted to make the aesthetic reflective judgment of beauty (including of artworks) objective but failed to do so (Nesher 2007, 2022).

The Peircean pragmaticist method can save the theory of knowledge both from the dogmatism of the metaphysical realists and from the inconsistency of the phenomenalists and holists. Peirce developed his epistemological realism in response to the difficulties of Kant’s transcendental epistemology, especially that of his three Critiques. This response was the conception of the three normative sciences: Theoretical, Ethical, and Aesthetical. In so doing, he articulated their different modes of representing reality and their normative roles, which make them Practical: Firstly, how theoretical sciences can practically help humans adjust to nature as well as change it so as to live better within it; secondly, how ethical science allows persons to adjust themselves to society and, more so, to change and develop it into the communal society that supports its citizens’ ethical values in their conducts, and so also the aesthetical science about the artists and their artworks representing their reality in a specific mode and in their intention to change it (1906, “The basis of pragmaticism in phaneroscopy” in EP 2; Nesher 2007).

Thus, Peirce, with his Realist epistemology, develops his conception of the three normative sciences to solve the epistemologically unbridgeable gaps between the transcendental a priori abstract forms and the experiential character of sensual matter in Kant’s three Critiques. This Peircean pragmaticist epistemology can help us to overcome Kant’s epistemological effects on the last two hundred years of philosophy, which cannot realize their philosophical ambitions because they lack any theory of truth to show how we cognitively represent noumenal reality.

2 Kant’s conception of metaphysics

The project on which I am now working … must be completed, or else a gap will remain in the critical philosophy. (Kant 1993 [1798]: 257)

The present writer was a pure Kantist until he was forced by successive steps into Pragmaticism. The Kantist has only to abjure from the bottom of his heart the proposition that a thing-in-itself can, however indirectly, be conceived; and then correct the details of Kant’s doctrine, and he will find himself to have become a Critical Common-Sensist. (1905, “Issues of pragmatism” in EP 2: 353–354)

According to Kant, in order to establish metaphysics as a science, a clear distinction must be made between the pure concepts of reason (the ideas) and the pure concepts of the understanding (the categories).

The concepts of reason (ideas) cannot be confirmed or refuted by experience because they do not appear in experience. On the other hand, the concepts of understanding appear in experience. They are confirmed by experience. (Kant 1950 PFM: 3rd Part, sec. 42)

The difficulty is that if the concepts of the understanding appear in experience and are also confirmed by experience, they cannot be axiomatic a priori, and their truth depends upon our empirical experience. The question, then, is whether this condition also holds with respect to the pure ideas of reason. If it does, this is a sort of Kantian overcoming of the transcendental basis of his epistemology. According to Kant, metaphysics is the outcome of our transcendental epistemology being the axiomatic system of pure rational concepts that are the basis of our phenomenological experiential but this can work only if the gap between the transcendental and the empirical can be overcome. What, then, is special about metaphisics?

Metaphysics is concerned with pure rational concepts. Metaphysics has to do not only with concepts of nature, which always find their application in experience but also with pure rational concepts, which never can be given in any possible experience whatsoever. Consequently, the objective reality of these concepts (viz., that they are not mere chimeras) and also the truth or falsity of metaphysical assertions cannot be discovered or confirmed by any experience. (PFM: 3rd Part, sec. 40)

The epistemological difficulty is to be explained from where we learned and received our rational concepts if they “cannot be discovered or confirmed by any experience” and whether the axiomatic objectivity of these concepts is constant or can be changed and, if so, how this can be done? However, according to Kant:

The concepts of reason aim at the completeness, i.e., the collective unity of all possible experience, and thereby go beyond every given experience. (PFM: 3rd Part, sec. 40)

The epistemological question is whether metaphysics can go beyond every given experience?

The objective reality of these concepts and the truth or falsity of metaphysical assertions cannot be discovered or confirmed by any experience. (PFM: 3rd Part, sec. 40)

Hence, the questions are: How can we know the a priori metaphysical concepts? And how we can demonstrate the truth or falsity of metaphysical assertions if they are known beyond any experience? Indeed, Kant made the distinction between the concepts of understanding and the ideas of reason because the first are to be connected to our experience if and only if we can overcome the gap between their formality and the materiality of experience. Moreover, this cannot hold for the ideas of reason and, thus, their truth or falsity is unexplainable, because transcendental reason cannot have axiomatic fake ideas since it is beyond any possible experience (PFM: 3rd Part, sec. 40).

How is it possible to know all possible experiences, to enable one to assume the applicability of metaphysics also for unknown future experiences? Realist epistemology can offer a solution to this predicament by suggesting that metaphysics is not accepted as a transcendental a priori assumption to supply the general picture of our experiential knowledge, but is developed gradually to understand our new experiential and scientific knowledge; it explains our general and abstract knowledge of reality as they continue to evolve as the general pictures of reality.

The distinction of ideas, i.e., of pure concepts of reason, from the categories, or pure concepts of the understanding, as cognitions of a quite different species, origin, and use is so important a point in founding a science which is to contain the system of all these a priori cognitions that, without this distinction, metaphysics is absolutely impossible or is at best a random, bungling attempt to build a castle in the air without knowledge of the materials or of their fitness for one purpose or another. (PFM: 3rd Part, sec. 41)

The above citations can support an epistemological move from transcendentalism to realism, since, without it, we cannot explain metaphysics as the universal cognitive picture of reality based on our experiential and scientific knowledge of reality. The epistemological endeavor is to show why transcendental pure and formal metaphysics cannot work if we understand that our knowledge of reality is extended continuously while, according to Kant, our metaphysics, as the general picture of reality, remains steady.

It is reasonable to suggest that metaphysics is the most general abstraction and generalization of our knowledge of Nature-Universe, which can lead us better to understand our particular knowledge in the framework of the general picture of Nature-Reality. Moreover, our metaphysics can change and develop with our progressive knowledge of reality and, thus, its general epistemic picture of reality can assist us in the conduct of our particular inquiries into reality, following Spinozist realism and Peircean Pragmaticism (Nesher 1978, 1979, 1987, 1999a, 2021).

3 Kant’s Pure Reason, the impossibility of knowing the reality of self and nature

Kant, in his Copernican Revolution, which aimed to overcome Humean empiricism, suggested starting with Transcendental a priori formal concepts to control our material sensual experiential intuitions, and yet had no method to combine them. Thus, Kant suggested his bizarre conception of schematism that cannot overcome the gap between the empty pure concepts of transcendental understanding and the blind objects of empirical intuitions. And, indeed, at the end of his inquiries, he admitted his failure to bridge this gap. Figure 1 is the schema that in a concise mode presents the epistemological structure of the First Critique.

Figure 1:

The evolvement of empirical concepts from blind sensual intuitions, with the pure intuitions and the empty pure concepts, into their habitual synthesis in perceptual judgment.

This schema (Figure 1) aims to explain the synthesis of the meaningless empty pure concepts of Pure Reason with the indeterminate meaning of the blind object, to make the concept meaningful and the object determinate. Thus, the empirical object can be determined by being subsumed under the pure concept. However, Kant’s Transcendental Epistemology is based on a mystical conception of the schematism meant to bridge between form and matter. Without it, his philosophical system cannot hold.

This schematism of our understanding, i.e., its schematism regarding appearances and their mere form, is the secret art residing in the depth of the human soul, an art whose true stratagems we shall hardly ever divine from nature and lay bare before ourselves. Only this much can we say: The image is [here] a product of the productive imagination’s empirical ability. (Kant 1996 CPuR: A141/B180–181; cf. A121, B185–187).

Hence, we can see that all Kant’s efforts in his first Critique to explain our scientific knowledge of nature through our phenomenal experiences cannot work in the transcendental epistemology. As I suggested above, after Peirce’s mature Realist epistemology, we must start from our empirical experience and from the proof of the truth of our perceptual judgments. Moreover, those judgments are our first cognitive facts upon them, we can develop our true scientific cognitions with our epistemic logic, which I developed from Peircean Pragmaticism and his eventual semiotic theory of truth (Nesher 2002b, 2010, 2011, 2018, 2021).

Thus, the evolution of the empirical concepts in perception from the sensual intuitions and imaginations into their synthesis in perceptual judgment reveals Kant’s difficulty with the transcendental epistemology of empirical concepts, which remain empty verbalizations. This is Kant’s nominalism as Peirce explains it (CPuR: 24-B150–151; 1905, “Issues of pragmatism” in EP 2).

4 Kant and his Pure Practical Reason and the impossibility of making morality in absolute freedom practical

The transcendental ground of Kant’s Critique of Practical Reason is the a priori assumption of the fact of pure practical reason, which uses the concept “fact” as a pure starting valid a priori from which he can develop his moral theory without any need for deductive justification to the experiential components of the system of the Pure Practical Reason, as in the first Critique.

The consciousness of this basic law may be called a fact of reason because one cannot reason it out from antecedent data of reason – e.g., from the consciousness of freedom (for this is not antecedently given to us) – and because, rather, it thrusts itself upon us on its own as a synthetic a priori proposition not based on any intuition, whether pure or empirical. (Kant 2002 CPrR: 31)

We can understand the status of fact as the basic assumption, accepted without any rational proof from other assumptions, as scientists use facts as certain true conditions for any scientific enterprise. The question is, how is it accepted? However, according to Peircean Pragmatist epistemology, the basic facts are not components of reality but the perceptual judgments proven to be true along with other scientific hypotheses which proved true (Nesher 2002b).

We can explain that moral principles and the moral concepts develop in our moral experience as part of the social behavior of humans in society and that their combination constitutes the personal and social Moral Law, which forms the major assumption for proving the eventual moral conduct (cf. Kant 1974 [1800]: #33). Aassuming or accepting that the truth or validity of the moral law cannot be done from nowhere as Kant seems to do (cf. CPrR: 42–50; Beck 1960: x, n. 2). Moreover, even if we assume the reality of the practical moral law of Pure Reason, we do not have any judgment that can be synthesized from the Pure Practical Law of Reason and from a particular sensible action in the world that would obligate moral action (cf. Cassirer 1938: 73–78). Since, according to Kant, we cannot represent moral actions in the world as aspects of physical events, but only as the concepts of Pure Practical Reason, we must have recourse to the concepts of the Understanding, which can represent such moral factual events (cf. CPrR: 67–68; Paton 1971 [1947]: 158–160). The question is whether the pure Understanding can mediate the supersensible concept of moral action with the sensible action-event in nature? This means that the pure Understanding with its operation will have to evaluate empirically the truth of the Moral Concept and Laws of the alleged Pure Practical Reason for the moral conduct, but this cannot be realized but only as is suggested in Peircean Pragmaticism (Cassirer 1938: 74; Kant 1987 CJ: 176; Nesher 2004b, 2005).

Hence, the proof, or the quasi-proof, of the truth of moral laws and their actionable application can be achieved only by our empirical knowledge of human nature and the social behavior of humans in their society, and the way to solve the Kantian predicament is to prove the truth of moral practical laws and the practical conducts (Kant 1974 [1800]: #33). Their imperative abstract actions in the sensual world will then be applied by the epistemological logic, the Peircean semiotics, the triadic of abductive discovery, deductive expectation, and by inductive evaluation the truth of moral imperative and thus, the reality of these laws and their application in the empirical world (cf. CPrR: 29–30). In this manner, we overcome the dichotomy between the supranatural world of freedom and the natural world of determinism and we understand freedom Spinozistically, as a person’s internal determination through self-conscious and self-controlled conduct according to the mental and physical laws of nature (cf. Nesher 1999b, 2007).

Kant’s formalism and his attempt to justify his Transcendental epistemology by deductive logic only, as he did in the first Critique and also in his formal mathematics, is superfluous for the Transcendental Morality since it separated epistemically from empirical reality being the a priori Pure Fact of Practical Reason and the following is the dilemma if it can be Practical in human life?

In Figure 2, we can see that Transcendental moral principles and concepts cannot have any cognitive relation to the practical moral objects-conducts in the sensual domain of practical life. Kant’s problem with apperception is that it cannot consider the empirical person and thus cannot explain the eventual connection between the Normative moral rule and the Practical concept of conduct. The eventual reason for such separation is that Kant, in order to avoid the relative experience of the logical judgment of the sensual experience of what Is, he has to ensure the validity or absolutism of the categorical imperatives of moral judgments, to be eternal and Ought, independent of our relative sensual experience.

Figure 2:

The Kantian eventual evolvement of the Rule of Conduct from the Principle of Ethic, with the Concept of Conduct being the object of the initial a priori moral concept.

It seems that Kant’s intuition was that the facticity of Pure Reason is necessary for our acceptance of the metaphysics of morals. However, to make the categorical imperative a priori, he avoided the experiential facts (Figure 3).

Figure 3:

Kant’s conception of the pure fact of practical reason and its role in the moral principles of virtue.

How can the Fact of Pure Reason be established and how can we be conscious of the moral law as the a priori fact of reason? Are the moral law and the freedom of rational persons’ reciprocal, when one assumes the other (Allison 1986; Kant 2012 GMM, 4: 446–448; CPrR: 29–31, 42)?

The epistemological conclusion must be that, in contrast with Theoretical Pure Reason, which, according to Kant, must be justified by deduction to explain its connection with sensual experience in the sensual world, Pure Practical Reason does not have to justify itself in the sensual-empirical world. This is so because it is the Fact of Pure Reason whose aspiration is to be practical by determine how the pure reason principles of morality determine the empirical subject’s moral deeds through dynamic laws of causality (CPrR: 42–43). And yet, this cannot be established in Kant’s transcendental pure practical reason due to the epistemological gap between the form of the Fact of Pure Reason principle of morality and the matter of moral deeds in the world of sense.

5 Kant and the impossibility of evaluating beauty rationally

According to Kant, in the aesthetic mood we reflect only on our perceptual operations, and, like animals, we feel instinctively the relationship between the cognitive operations of the Imagination and of the Understanding, without explicit rules and concepts (CJ: First Introduction, V, 211′). As Kant suggests, our feeling, in response to the relationship between these faculties, can be of pleasure or displeasure, depending on whether we feel that the relationship between these cognitive faculties is harmonious or disharmonious. Thus, he suggested that the form of an object (“beautiful”) presents the quasi-object, and, more specifically, our “feeling” it as beautiful (Figure 4).

Figure 4:

Reflective suggesting the universal quasi-concept for the given particular quasi-object: Aesthetic Reflective Judgment (CJ: 287).

The conceptions of the quasi-rule and the quasi-object show that we do not cognize them under any principles or concepts, but by our habitual pre-rational cognitions, through instinctive and practical reflecting the outcome of such operations, while reflective judgment is only indeterminate rationally, is only subjective feelings in distinction from rationally determinated proved true aesthetic judgment.

When we reflect (even animals reflect though only instinctively, i.e., in reference not to acquiring a concept, but to – say – determining an inclination), we need a principle just as much as we do when we determine, where the underlying concept of the object prescribes the rule to judgment and so takes the place of the principle. The principle by which we reflect on given objects of nature is this: that for all natural things, concepts can be found that are determined empirically … For if we were not allowed to presuppose this, and did not base our treatment of empirical presentations on this principle, then all our reflections would be performed merely haphazardly and blindly, and hence without our having basis for expecting that this [reflection] is in agreement with nature. (CJ: V, 211′–212′; cf. V, 211′–216′; Nesher 2002a)

Indeed, we have to understand the difference between reflection in general, which is instinctive and practical, and the rational, self-conscious, and self-controlled operation of our cognition, whereby the former is used in determining an inclination and the latter in determining intention, knowledge and conduct. However, this is different from the reflection involved in aesthetic judgment, which controls only our subjective feelings of pleasure and beauty, without constituting any knowledge of objects, as is the case with the logical judgment, and yet it is not “performed merely haphazardly and blindly” (CJ: V, 211′–212′). The artist achieves beauty in a created artwork when he is satisfied with the harmony that exists between his intellectual ideas and the aesthetic ideas exhibited in the art (Figure 5). But how can this be explained? Is it possible given Kant’s conception of the reflective judgment of subjective feeling, without being established to be true and public under its proof-conditions, or, rather, perhaps it cannot be an aesthetic judgment?

Figure 5:

The union of Kant’s genuine creation of artwork and the reflective judgment of taste.

The problem is to reconstruct Kantian aesthetics to show how the creation and evaluation of the beauty of an artwork can be objective and true, rather than merely the subjective experience of pleasure and displeasure of reflective judgment (cf. CJ: 241; Nesher 2022). Creating beautiful artworks is the coherent interpretation of the intellectual ideas of the artists in their exhibition of aesthetic ideas, which, as proved true they represent aesthetically the experienced reality. According to Kant, an artist’s reflective judgment of this creativity is based on instinctive and practical of their free play of ideas of the Understanding and the productive Imagination, to attain only intuitively subjective feeling.

Regarding reflective judgments, these are based on the artist’s imagination, which, according to Kant, affords a comparison between the aesthetic artwork and the known facts of reality. Such judgments render not only pictorial images, but also intense reactions. However, such aesthetic presentation (Vorstellung) of reality is achieved by the emotional images evoked through the contemplation of the aesthetic artwork, which is already infused with the intellectual ideas of the artist, which we can elicit from the context of the specific work’s creation. Moreover, by reasoning and discussing, we can come to agree on its beauty as an aesthetic presentation of reality.

Now, for Kant, there are two different conceptions of judgment, cognitive logical judgment and reflective aesthetic judgment. The synthesis in the former is based on the imaginative reflective self-control of the relation between the Imagination and the Understanding in presenting an object, while the synthesis in the latter, though based on the reflective self-control of the relation between the Understanding and the Imagination, is just the subject’s feeling, without any aesthetic representation (Darstellung) of any objects as the criterion for its truth.

In the Peircean theory of perception we can find the prototype of the structure and operation of the human mind confronting in reality. According to its particular combination of the basic components of the perceptual operation, first, the Imagination (in aesthetic judgment), second is Reasoning-Volition (in moral judgment), and the third is rational Understanding (in theoretical judgment). These are the embryos of Kant’s Three Critiques and of Peirce’s three normative sciences representing Reality: Aesthetically, Emotionally and Rationally (e.g., CPrR: 33–34, 109–110; MS 283, 1907, “The basis pragmaticism in the normative sciences” in EP 2; Nesher 2022).

Considering the Pragmaticist epistemology of creating and evaluating artworks we find that the historical theories of art and aesthetic movements with their manifestos emphasized only some of the aspects of methodical artistic practice. Art historians nevertheless consider these aspects to be the only essential elements of artistic creation and evaluation. The focus is on the aesthetic or the intellectual ideas of the artists, on the content and the form of the artist’s intentions in the creation of works of art, on feelings of harmony or the representation of reality, on the feeling of the truth of the artwork, on the sincerity of the author-artist, and so on (Faulkner and Ziegfeld 1969: 430). Figure 6 is the Peircean reconstruction of the Kantian intuition of artistic creation and the evaluation of artworks, and the three stages of artistic creation and the evaluation of artwork as representing reality, based upon common-sense knowledge being the accepted knowledge of our three normative sciences, theoretic, ethic, and aesthetic:

Figure 6:

The artist’s creation of artwork and his reflective free play to harmonize intellectual ideas and aesthetic ideas: The role of productive imagination.

The artist with his spirit and productive imaginative free play interprets the generality of intellectual ideas into the singularity of aesthetic ideas and thus exhibits the intended artwork. With such a quasi-deductive inference the artist exercises, a la Kant, the reflective manner (modus aestheticus) to achieve the harmonious interpretation between the ideas of the Understanding and the Imagination, and the unity of aesthetic ideas of the created artwork. This is an elaboration of Kantian aesthetics, but replaces his subjective conception of harmony with the Peircean realist confrontation in reality, which can be the objective criterion of truth and beauty. Indeed, such reality is represented by the common-sense knowledge of reality, which is the historical accumulation of our perceptual and scientific knowledge, which is available to the artists in the creation and evaluation of their artworks (CJ: 1781–1787; Nesher 1994a, 2022).

The difficulty is to explain the principal role of art and the aim of the artist: is it to imitate nature, to decorate our lives, to entertain us, or rather to represent reality to guide our conduct in it and to prompt us to be involved in moral activities and political movements that would change reality according to the knowledge and the impetus we receive from the created artworks? It is interesting to explain how a piece of artwork can affect our cognitions to help and elaborate our social, moral, and intellectual conduct in reality. Indeed, like other personal interactions, the artist, by expressing his intellectual ideas of reality and imaginatively creating aesthetic ideas – as embodied in the artwork – to be an aesthetic representation of reality, allows us to contemplate and enjoy the created aesthetic images, like Don Quixote or Anna Karenina, and affect our own spiritual images, which are beautiful precisely because they express our understanding of our own life. In other words, art’s purpose is to allow us to bring to mind the truth about ourselves, and thereby to become aware of who we truly are and how we are to behave in life. Art, therefore, is not just for art’s sake, but for knowledge and beauty’s sake, for the sake of a distinctively sensuous form of human self-expression and self-understanding.

6 Kant on formal logic and pure mathematics

Kant, is trying to explain in his epistemological enterprise if and how humans can develop their knowledge of phenomenal reality and the role of the sensuous cognition in it.

After all philosophical insight into the nature of sensuous cognition was spoiled by making sensibility merely a confused mode of representation, according to which we still know things as they are, but without being able to reduce everything in this our representation to a clear consciousness. I proved that sensibility consists, not in this logical distinction of clearness and obscurity, but in the genetic one of the origin of knowledge itself. For sense perception represents things not at all as they are but only the mode in which they affect our senses; and consequently by sensuous perception appearances only, and not things themselves, are given to the understanding for reflection. After this necessary correction an objection rises from as unpardonable and almost intentional misconception, as if any doctrine turned all the things of the world of sense into mere illusion. (PFM: 290–291)

This explanation is essential for the explanation of the role of sensuous cognition in human knowledge of reality and even might explain how Peirce developed his cognitive semiotics; it can also explain our proof of the truth of perceptual judgments as our basic knowledge of reality. However, this important intuition of Kant’s does not solve the difficulty of how sensuous cognition connects with the rational logical-perceptual judgments as the basis of all our knowledge of reality or the question of how formal logic and pure mathematics work.

6.1 On formal logic

Kant in his Logic (1800) is trying to summarize his conception of formal logic, the pure transcendental logic and of pure mathematics and its relation to the empirical sciences such that formal logic is the axiomatic system of the rules of thinking including the universal grammar of language. The following are some discussions of Kant on logic and mathematics in his Logic:

All rules according to which the understanding proceeds are either necessary or contingent. The former are those without which no use of the understanding would be possible at all; the latter are those without which a certain use of the understanding would not take place. The contingent rules which depend on a certain object of cognition are as variegated as these objects themselves. Thus, for example, there is a use of the understanding in mathematics, metaphysics, morality, etc. The rules of such special determinate use of the understanding in the said sciences are contingent, because it is contingent whether I think this or that object to which these rules related. (Kant 1974 [1800]: 14)

Logic is separated from any relation to reality but is the upper structure of all other applied formalisms, i.e., transcendental logic with its necessary or contingent relations to sensual intuition of objects and pure mathematics with its application to counting numbers and more. However, transcendental logic and formal mathematics are pure axiomatic systems; they either are necessary by virtue of being separated from empirical reality or contingent in their eventual application to reality. However, according to Kant, it is an a priori formal condition for human contingent reasoning while the explanation of how it is embedded in human experience and knowledge remains unexplainable due to the unbridgeable gap between the Transcendental axiomatic empty formalism and the empirical vague sensual intuition (Figure 7).

If, now, we set aside all cognitions that we must borrow from objects and reflect solely upon the use of the understanding in itself, we discover those of its rules which are necessary throughout, in every respect and regardless of any special objects, because without them we would not think at all. Insight into these rules can therefore be gained a priori and independently of any experience, because they are containing, without discrimination between objects, merely the conditions of the use of the understanding itself, be it pure or empirical. And it also follows from this that the universal and necessary rules of thought in general can concern solely in form, and not in any way its matter. Accordingly, the science containing these universal and necessary rules is the science of the mere form of our intellectual cognition or of thinking. And we can therefore form for ourselves the idea of the possibility of such a science, just as that of universal grammar which contains nothing beyond the more form of language in general, without words, which belong to the matter of language. (Kant 1974 [1800]: 14–15; cf. Chomsky 1965)

Figure 7:

Transcendental logic and pure mathematics in pure intuition.

Indeed, Kant endeavored in his late researches to make his epistemology more pragmatic by the distinction in the operation of Understanding between necessary and contingent, namely the formalistic and also a Realistic presentation of reality and yet, due to the a priori and formalist conception of reason and understanding it seems that he could not solve Humean skepticism about empiricism.

Logic is a science of reason not only as to mere form but also as to matter; a science a priori of the necessary laws of thinking, not, however, in respect of particular objects but all objects generatim; it is a science, therefore, of the right use of the understanding and of reason as such, not subjectively, i.e., not according to empirical (psychological) principles of how the understanding thinks, but objectively, i.e., according to a priori principles of how it ought to think. (Kant 1974 [1800]: 18–19)

However, Kant cannot bridge the gap between formal rationalism and material empiricism. This stands in contrast to Peirce’s Pragmaticism. Peirce developed his semiotics to explain how from empirical experience we cognitively develop our rational cognitions to prove their true representation of reality. This is not absolute proof but is relative to our available internal and external proof-conditions as I also explain in my epistemic logic (Nesher 2002b, 2021).

Indeed, Pure Mathematics, operating under the Transcendental Logic is the basis of its formal operations but nevertheless remains an axiomatic determination without explaining any relation to empirical reality. Moreover, the empirical sciences as operating under formal logic and pure mathematics are, according to Kant separated from experience but yet embedded in human experience through the natural and social sciences. This seems unexplainable. Nevertheless, the rules of formal logic and pure mathematics operate differently in different sciences. They can be regarded as the different methodologies of the different empirical sciences, Theoretic, Ethic and Aesthetic.

The epistemological difficulty for Kant is to explain how the formalism of the Transcendental Logic and pure mathematics can be connected to the experiential sciences. For this, they must be embedded in both, the formalism of logic and mathematics with the matter of sensual intuition and empirical experience. Kant’s schematism cannot help them cross the border into phenomenal reality. The union of empiricism and rationalism can, however, be achieved by Peircean Pragmaticism by proving the truth of perceptual facts using semiotic operations as our epistemic logic. This can explain our mathematical-arithmetical operations with signs-numbers upon physical objects and thus representing mathematical reality. This can be extended to the mental and physical sciences (Nesher 2021).

The interesting epistemological question is whether Kant himself, with his brilliant philosophical intuitions, can come close to explaining mathematical operations and their knowledge of reality without turning to the Platonist’s enigmatic suggestion? It seems that in the paragraphs following the quotations from his Prolegomena above, Kant comes close to an empirical explanation of our knowledge. Peirce reconstructed such intuitions to construct his Realist epistemology (PFM: 290–291).

6.2 On pure mathematics

Kant based his epistemological conception of pure mathematics on his analysis of the structure and operation of the syllogism. This was the conception of the axiomatic systems of Transcendental Logic and pure mathematics. Kant’s Transcendental Epistemology is based on the eventual union of formal concepts and material sensual intuitions, transforming them into empirical concepts giving rise to logical-perceptual judgments. This unity is based on the mystical concept of schematism, introduced in order to bridge this gap. Without bridging this gap, the Kantian philosophical system cannot hold and formal logic and pure mathematics remain empty signs and words and are ultimately meaningless. However, since Kant assumed that mathematics is a pure science, based on Transcendental pure intuition, he encountered difficulties explaining intuition and in his Critique of Pure Reason, he explains, simile experiential operation, the basic mathematical pure sensible intuition of counting fingers or dots.

Platonist mathematical entities as “pure sensible objects” are not visual images based on experience, and thus, according to Kant, they are based on schemata that exist only in pure thought; any particular image could not be as general as the concept of an object (CPuR: A141). In contrast with Kant’s basic conception of logical judgment presenting phenomenal objects and the upper Transcendental part of such judgment as in Figure 7, Kant presents his conception of pure mathematical science as based on the pure intuition of the Understanding of space and time.

Now, the intuition which pure mathematics lays at the foundation of all its cognitions and judgments which appear at once apodictic and necessary are space and time. For mathematics must first present all its concepts in intuition, and pure mathematics in pure intuition; that is, it must construct them. If it proceeded in any other way, it would be impossible to take a single step; for mathematics proceeds, not analytically by dissection of concepts, but synthetically, and if pure intuition be wanting there is nothing in which the matter for synthetical judgments a priori can be given. Geometry is based upon the pure intuition of space. Arithmetic achieves its concept of number by the successive addition of units in time … (PFM: 282–283; Hintikka 1973)

In distinction from the Kantian conception of pure mathematics we can elaborate the Realist conception of mathematics based on Peircean semiotics, that I elaborated into Epistemic Logic. This can show how mathematics can be an empirical science (Nesher 2010, 2011, 2018, 2021).

However, Kant’s Transcendental Epistemology is based on the mystical conception of schematism, to bridge between form and matter; without it, his philosophical system cannot hold and pure empty concepts remain meaningless as nominal empty words and blind objects remain vague feelings only (CPuR: #24-B150–151). In Figure 7, Kant artificially binds the experiential components of the Transcendental epistemology. According to my interpretation, Peirce criticizes it and constructs his Realist epistemology to revolutionize Kant’s Transcendental epistemology.

Figure 7 can explain the attempted synthesis of the indeterminate meaning of the sensual blind object with the empty pure concept, which thereby Kant intended to make the concept meaningful and the object determinate and thus, the empirical object can be determined by being subsumed under the empirical concept (CPuR: #24-B150–151). Since Kant assumed that mathematics is pure science, based on transcendental pure intuition, he had difficulties explaining this intuition, and, in his Critique of Pure Reason B (1996 [1787]), he explains the basic the counting fingers or dots in pure mathematical intuition.

In thinking merely that union of seven and five, I have by no means already thought the concept of twelve; and no matter how long I dissect my concept of such possible sum, still I shall never find in it that twelve. We must go beyond these concepts and avail ourselves of the intuition corresponding to one of the two: e.g., our five fingers or (as Segner does in his Arithmetic) five dots. In this way we must gradually add, the units of the five given in intuition … For then it is very evident that, no matter how much we twist and turn our concepts, we can never find the [number of the] sum by merely dissecting our concepts, i.e., without availing ourselves of intuition. (CPuR: B14–15)

The first epistemological difficulty is with numbers, whether they are ideas-signs or objects, and this can be seen from the semantic structure of the signs-symbols in Figure 8: The Realist Platonic Ideas on the left and Nominalist Phenomenal Object on the right side. The epistemological difficulties of mathematics include: what are numbers, objects of signs or signs of objects, and what is mathematics and what is mathematical proof (Russell 1918 [1901]).

Figure 8:

The structure of a cognitive symbolic-type sign is a hierarchy of its components: The distinction between Platonist Realist Ideas, scholastic nominalist Objects and empirical Realist Operations.

Indeed, number signs cannot be objects or concepts of empirical experience, but are discovered signs, components of the human empirical operations of Counting, Grouping, and Measuring physical objects (Nesher 2011). The discovery of the concepts of these operations of enumeration and grouping, which contain natural numbers, and further discovery of their expansion through abstractions and generalizations, constitute our mathematical hypotheses, which will be evaluated and proved upon extended mathematical reality (Krantz 2011). Hence, by proving the truth of perceptual facts representing our mathematical-arithmetical operations with signs-numbers upon physical objects, we represent mathematical reality. The interesting epistemological question is whether Kant himself, with his philosophically brilliant intuitions, can come close to explaining mathematical experience in reality, to explaining its knowledge, without turning to the Platonist’s enigmatic suggestion? It seems that in the paragraphs from his Prolegomena (1950 [1783]), Kant seems to come toward an empirical explanation of our knowledge, which seems to be a hint for Peirce to reconstruct from such intuitions to construct his Realist epistemology. Hence the Kantian conception of Formal Logic and Pure Mathematics operate only in deductive inferences as axiomatic closed systems, which can engage in inference without any proof of truth. Hence, they cannot be sciences, which can prove the truth of their hypotheses in relation to reality.

The alternative epistemology for the mathematical formal inferences as Pure Formal Game is to elaborate it to Empirical Theory. Indeed, the number-signs cannot be of objects of empirical experience but are the discovered components of the human empirical operations of counting, grouping, and measuring physical objects (Krantz 2011; Nesher 2011). Hence, by proving the truth of perceptual facts representing mathematical operations we represent mathematical reality (Figure 9).

Figure 9:

The double layer of mathematical operations: (1) counting physical objects; (2) perceptual quasi-proving the truth of discovering the numerical signs and of operating with them.

By understanding that mathematical reality consists of perceptually self-controlled numerical operations on physical objects, we can see how Peirce, and also Gödel, confuse the meaning-content of mathematical signs with Platonist mathematical abstract forms as objects. Arithmetical numbers are neither physical objects nor abstract concepts but the conceptual components of our quantitative operations on physical objects, as mathematical reality, and upon it we prove the truth or falsity of our abstract mathematical hypotheses (Nesher 2011). Without operationally measuring the predicted and eventually observed true facts of reality mathematics cannot be true and cannot be “on a much firmer ground” than physics without “a testable prediction.” Both have to prove their own truths upon “their different ways of approaching the world.”

However mathematical intuition in addition creates the conviction that, if these formulas express observable facts and were obtained by applying mathematics to verified physical laws (or if they express ascertainable mathematical facts), then these facts will be brought out by observation (or computation). (Gödel 1995 [1953]: III, #16; cf. #13–15 and n. 34)

How may one understand this hinted explication of the relationship between intuitive mathematical truth representing its own reality and its application to physical theories to enable their observable predictions (Gödel 1995 [1953]: II, #15)? At the end, mathematics is neither the queen of science nor its servant but its quantitative backbone – that is, the quantified formulations of scientific theoretical hypotheses and their operations in scientific observations – without which physical and other theories cannot be evaluated experimentally. The explanation of the puzzlement of why mathematics is considered to be an exact or pure science, while being empirical like other experimental sciences, is the relative simplicity of its represented reality with respect to physical and psychological realities. This empirical explanation can be seen in Gödel’s late philosophical writings on the foundations of mathematics:

If mathematics describes an objective world just like physics, there is no reason why inductive methods should not be applied in mathematics just the same as in physics. … This whole consideration incidentally shows that the philosophical implications of the mathematical facts explained do not lie entirely on the side of rationalistic or idealistic philosophy, but that in one respect they favor the empiricist viewpoint. It is true that only the second alternative points in this direction. (Gödel 1995 [1951]: 313)

We can know experientially the mathematical facts of mathematical empirical reality.

7 Kant’s failure with his three Critiques and his looking to save them from his pragmatic point of view

To sum up the evaluation of Kantian transcendental epistemology, metaphysics, and philosophy, I suggest that, in his Critique of Pure Reason, he tried to combine Cartesian rationalism and Humean empiricism, which, taken separately, could not explain our knowledge of nature (Norton 1993). Kant tried to combine them as the Transcendental-formal reason and Understanding along with the experiential Sensual intuition of matter. Ultimately, he admitted that he cannot cross the gap between them and therefore cannot explain our knowledge of nature. We can say that he invited us to criticize his Critique of Pure Reason. Moreover, Kant’s Critique of Practical Reason aims to criticize the practicality of moral concepts and laws and freedom of the will and to introduce moral law and freedom, which must be a Pure Fact of Reason, so as to make the moral laws the absolute categorical imperative of moral judgments. But, then, how can we determine our moral conduct?

How could the moral law of determination make the concepts of objects of practical reason actual if not through actual persons in their conduct, as components of the world-nature that can affect themselves, their society, and the environment? The difficulty with Practical Pure Reason is that without connection to sensual intuitions and reality, it cannot be practical in its full sense of human social action.

Hence an immense gulf is fixed between the domain of the concept of nature, the sensible, and the domain of the concept of freedom, the supersensible, so that no transition from the sensible to the supersensible (and hence by means of the theoretical use of reason) is possible, just as if they were two different worlds … (CJ: 176)

Moreover, Kant’s formalism and his attempt to justify his Transcendental Epistemology deductively, as in his formal logic for pure mathematics, cannot prove the truth of our cognitions to be our knowledge representing reality and it cannot prove the free reason-causation of human moral conduct.

The problem is to reconstruct the Kantian aesthetics in his third Critique to be able to show how the creation and evaluation of the beauty of artworks can be objective and true, rather than, as Kant takes it, just a subjective experience of pleasure and displeasure of the reflective judgment, without any criterion and proof of its truth or falsity (cf. CJ: 241; Nesher 2022). A realistic alternative is that creating beautiful artworks is the true interpretation of the intellectual ideas of the artists in their exhibition of aesthetic ideas, which can be proved true as they represent aesthetically the experienced artistic reality. However, according to Kant, an artist’s reflective judgment of this creativity is based on instinctive and practical free play with ideas of the Understanding and the productive Imagination in order to attain the subjective feelings of beauty or ugliness, without any proof of truth or falsity as an objective criterion. Hence, it is actually the critique of reflective judgment and not a real judgment but subjective feeling.

8 Kant, in his late research attempted to find pragmatic explanations to solve his epistemological difficulties but failed (APPV)

Kant’s distinction between Is and Ought with respect to his Transcendental a priori account of moral concepts and rules aims to show that the categorical imperatives are independent of all empirical experience and knowledge. Yet this means that they must also be independent of moral practice. From where did Kant develop his transcendental conception of morality, the a priori Fact of Pure Reason, if not from his empirical experience in society? This relation remains only intuitive and unexplainable in his Transcendental epistemology. The difficulty is how Kant can intuitively arrive at the absolute moral Ought merely from knowledge of what Is, i.e., relative empirical knowledge of human moral conduct including his own? It seems that the idealizations of the categorical imperatives and the kingdom of ends are conceived only to show our ideal expectations to assign human resolve, which cannot be achieved practically.

This can be seen as similar to the theory of absolute truth, that we can never know but only visualize, since, according to neo-Kantians, like Popper, Putnam, Hintikka and others, who actually identify absolute truth with unknown reality, we cannot accept relative truth. Nonetheless, pragmatically, we prove our hypotheses based upon our available-accepted proof-conditions. Perhaps Kant might suggest that relative moral rules that are practically proved true are to be used in personal and social life, which cannot be any ideal aim to try to look for. And yet, without an empirical epistemology of truth and practical morality, we cannot even think about them and their idealizations. Hence, it can be concluded that we cannot move from the Is of our empirical experience matter-meaning to the Ought of our expectations, which without our experience it remains meaningless formalism and therefore, inapplicable to our Is with respect to our practical moral conducts and cannot affect our personal and social life. Indeed, in 1790 Kant became more pragmatic and made the distinction between the final purpose we strive toward and the highest good in the world that we can achieve, similar to Spinoza (CJ: 450; Nesher 1994b, 1999a).

The moral law is reason’s formal condition for the use of our freedom and hence obligates us all by itself, independently of any purpose whatever as material condition. But it also determines for us, and a priori, a final purpose, and makes it obligatory for us to strive toward [achieving] it; and that purpose is the highest good in the world that we can achieve through freedom. (CJ: 450)

This was Kant’s endeavor, to explain in his Anthropology from a Pragmatic Point of View that the moral empirical-meaning matter cannot be understood without the form of the Transcendental moral concepts and laws such that the final purpose will eventually direct practical conduct (cf. APPV: Book III: On The Faculty of Desire). However, in Kant’s Transcendental presuppositions of the knowledge of physical reality, that cannot overcome the gap between Pure Reason and Understanding with their a priori assumptions without his mystical, imaginative schematism, that cannot serve as a bridge between the a priori empty pure concepts and the sensual blind objects the evolvement of the empirical concepts cannot be achieved and the logical judgment, as the basis of all our knowledge of nature, cannot be formed. Therefore, the question is whether the known final purpose of morality can make it obligatory for us to strive toward gradually achieving the highest good in the world through a relative freedom and makes it obligatory for us to strive toward practical moral conduct?

Hence, it is interesting to explain the Kantian conception, and the role, of Empirical Apperception in Peircean Realist epistemology for the proof of the truth of the Normative Moral Rule of Conduct (Figure 10).

Figure 10:

The Kantian pragmatic point of view elevating the experience of empirical cognition into the unity of intuition and rational discursive by, let us say as epistemic logic.

Does the Practice of Pure Practical Reason Ought hint to the practical Deed Is in society (APPV: #7)?

We cannot prove the practicality of the Ought of Pure Practical Reason by intention only “to strive toward it” without proving the truth of our knowledge of the social reality Is. Yet this cannot be done by Kant, since he could not explain with his Transcendental logic how we can know how the Pure Understanding and Pure Reason can eventually reach the reality they intend to, the sensual intuition of objects and pure moral practice, respectively, to reach the deed in the real world and to prove its true representation of the cognitive relation of Is-Ought-Is, as we can see in the following:

Hence it must be possible to think of matter as being such that the lawfulness in its form will harmonize with at least the possibility of [achieving] the purposes that we are to achieve in nature according to laws of freedom. So there must after all be a basis uniting the supersensible that underlies nature and the supersensible that the concept of freedom contains practically, even though the concept of this basis does not reach cognition of it either theoretically or practically and hence does not have a domain of its own, it does make possible the transition from our way of thinking in terms of principles of nature to our way of thinking in terms of principles of freedom. (CJ: 176; cf. CPuR: B xxi; Guyer 2005)

Hence, we can see that Kant endeavors to explain the possibility of the Pure Practical Reason in its practicality, to reach from the transcendental domain of reason into the sensual domain of experience, to make possible the effect of the moral laws of freedom upon our moral conduct in the sensual domain, the practical conduct in society and nature. For this Kant had to assume the supersensible domain to support his transcendental conception of moral practice yet we cannot know this noumenal domain but only divine it. This is similar to the assumption of the schematism as an operation that we cannot know, in order to connect the Transcendental Understanding a priori concepts with the sensual experience to save the possibility the theoretical knowledge initiated in our logical judgments (Paton 1971 [1947]: ch. 22).

This Kantian endeavor with the supersensible domain comes close to Spinoza’s conception of nature-substance that contains the union of two attributes: extension and intention including the human body and mind, and thus the mental and the physical are united in nature. The physical causality with human practical freedom and yet, freedom is the inner causality of the subject but only relative to the individual inner power (conatus) in the domain of nature one lives in, and not the absolute fact of the Pure Practical Reason. It is quite possible that Kant by looking to the writings of Spinoza he imagined that the supersensible can work as the common-dominator of physical and psychical domains and yet the Spinoza’s nature is knowable bur not so the Kantian supersensible domain. The alternative to the Kantian gap between transcendentalism and empiricism is Spinozist epistemology that considers that the mental and the physical are two components, attributes of the substance-nature in which everything is in nature. This does away the need to invent the unknown domain of supersensible-noumenon domain for explaining the practical moral conduct.

The Spinozist ethical theory is that human freedom is relative to one’s knowledge of oneself and the reality one lives in, and the truth of which is relative to the available proof-conditions, entails that any human freedom is relative to one’s personal knowledge and power in respect to the power of reality one lives in and conducts oneself in to implement one’s ethical concepts and conduct. According to Spinoza, our freedom in nature is the personal inner causality, the conatus, which is relative to our knowledge of ourselves and power of the external reality in which we endeavor to implement our ethical dictates of reason. Moreover, this epistemology overcomes the gap between the Kantian absolute moral freedom which cannot realize the ideal categorical imperatives which cannot be implemented in practical deeds (Nesher 1994b, 1999a).

This epistemological explanation, à la Spinoza, can show how our knowledge of ourselves and physical nature allows us to theorize about ethics and to explain ethical conduct, as opposed to the Kantian impasse between the form of Pure Practical Reason and the Sensual Intuitions of objects and human moral conduct. The epistemological question: Is Kant’s Anthropology from a Pragmatic Point of View a continuation of his Transcendental critical philosophy or his intended empirical epistemology by which to develop a practical deviation from his Copernican Revolution in the direction of the Peircean contra-revolution, as developed in the latter’s Pragmaticist epistemology?

Transition from metaphysics of morals to the critique of practical reason

The concept of freedom is the key to the explanation of the autonomy of the will. (GMM, 4: 446–463)

The counterpart of a metaphysics of morals … would be moral anthropology, which, however, would deal only with the subjective conditions in human nature that hinder people or help them in Fulfilling the laws of a metaphysics of morals. It would deal with the development, spreading, and strengthening of moral principles (in education in schools and in popular instruction), and with other similar teachings and precepts based on experience. (GMM, 6: 217)

It seems that Kant develops his empirical anthropology in order to connect his laws of the metaphysics of morals with their employment in humans’ experience and conduct in life.

Everything gravitates ultimately toward the practical; and in this tendency of everything theoretical and everything speculative in respect to its use consist the practical value of our cognition. This value, however, is an unconditioned value only if the end to which the practical use of cognition is directed is an unconditioned end. The only unconditioned and final end (ultimate end) to which all practical use of our cognition must lastly refer is morality, which for that reason we also call the plainly or absolutely practical. And that part of philosophy which has morality as its object would accordingly have to be called practical philosophy …, although every other philosophical science may also contain its practical part, that is a direction concerning the practical use of the theories set forth, for the purpose of realizing certain ends. (Kant 1974 [1800]: 94–95)

It is interesting to see that Kant, probably at the end of his philosophical career, accepted that all our cognitions are intended to practical use, which differ from his First and Third Critiques but the difference between theoretical and aesthetical disciplines in which the freedom to reach the practical uses is natural and relative in distinction from the Pure Practical Reason in which the condition of morality is absolute freedom for the categorical imperatives since otherwise no morality can work (Nesher 1994b, 1999a, 2002b: x).

The theoretical and aesthetic disciplines, in which the freedom is to reach the practical conducts is natural and relative, are distinct from Pure Practical Reason, in which the condition of morality is absolute freedom to operate the categorical imperatives since no morality can work otherwise. Indeed, as in Spinoza’s Ethics, all our cognitions are proved true relative to their proof-conditions and our moral rules, and the freedom to apply them practically depends on our knowledge of ourselves and the reality we operate in, which historically changes and evolves with the structure of societies (Spinoza’s Ethica; Nesher 1994b, 1999a, 2002b: X). Kant’s late, general, conception of knowledge and practice probably influenced Peirce in his development of the conception of the three normative sciences, Theoretical, Ethical, and Aesthetical, as aimed practically to elevate human life in nature and society (1906, “The basis of pragmaticism in phaneroscopy” in EP 2; Nesher 2007).

It seems that Kant, in his late writing, is trying to understand the “pure interest of reason” to conform to ordinary knowledge; that is, to explain pure reasoning as connected to empirical reasoning that includes intentional inclination not only as an empty form, but also as matter, yet still without relation to objects, as a sense-free inclination (cf. CJ: V, 211′–212′).

But just as there must be principles in a metaphysics of nature for applying those highest universal principles of nature in general to objects of experience, a metaphysics of morals cannot dispense with principles of application, and we shall often have to take as our object the particular nature of human beings, which is cognized only by experience, in order to show in it what can be inferred from universal moral principles. But this will in no way detract from the purity of these principles or cast doubt on their a priori source. – This is to say, in effect, that a metaphysics of morals cannot be based upon anthropology but can still be applied to it.

The counterpart of a metaphysics of morals, the other member of the division of practical philosophy as a whole, would be moral anthropology, which, however, would deal only with the subjective conditions in human nature that hinder people or help them in fulfilling the laws of a metaphysics of morals. (GMM, 6: 216–217)

The first epistemological difficulty is how anthropology is possible as a science if it is only subjective. The subjectivity of anthropology is evident from the fact that it is based on reflective judgments, which, as in the aesthetic domain, are based only on subjective feelings. Moreover, how can Kant bridge the gap between the pure reason of morality and the sensual experience of anthropology without the help of the pure Understanding, without which knowledge of nature is completely impossible? In the end, this must lead Kant to skepticism about the possibility of making pure practical morality practical in real human life (Nesher 2022: ch. 5). Peirce tries to solve this Kantian difficulty.

Since the normative sciences are usually held to be three, Aesthetics, Ethics, and Logic, and since he, too, makes them three, he would term the mid-normative sciences ethics if this did not seem to be forbidden by the received conception of the term. He accordingly proposes to name the mid-normative science, as such (whatever its content may be), Antethics, that is, that which is put in place of ethics, the usual second member of the trio. It is the writer’s opinion that this Antethics should be the theory of the conformity of action to an ideal. Its name, as such, will naturally be practics. Ethics is not practics, first, because ethics involves more than the theory of such conformity; namely, it involves the theory of the ideal itself, the nature of the summum bonum; and secondly, because, in so far as ethics studies the conformity of conduct to an ideal, it is limited to a particular ideal, which, whatever the professions of moralists may be, is, in fact, nothing but a sort of composite photograph of the conscience of the members of the community. In short, it is nothing but a traditional standard, accepted, very wisely, without radical criticism, but with silly pretense of critical examination. The science of morality, virtuous conduct, right living, can hardly claim a place among the heuretic sciences. (1906, “The basis of pragmatism in the normative sciences” in EP 2: 377)

Of the Normative Sciences, three are generally recognized, relating respectively to how our Feelings, our Energies, and our Thought should be self-directed. (1911, “A sketch of logical critics” in EP 2: 459; cf. 1903, “The three normative sciences,” “An outline classification of the sciences,” “The ethics of terminology,” in EP 2; also 1906, “The basis of pragmatism in the normative sciences” in EP 2: 371, 377 “heuretic science” – empirical)

The question is about Peirce’s conception of the normative sciences: first, how do they endeavor to represent different segments-domains of reality, and second, how do they do so? Moreover, logic, not theoretical science, can do so, since logic, or, better, the epistemic logic that represents our cognitive confrontation with reality, is an essential component of any normative science, and indeed, all cognitions, implicitly, practically and rationally (Nesher 2018, 2021). Epistemic logic is, let us say, the Boolean “laws of thought,” representing our cognitive confrontation in reality, which enables us to sustain our self-controlled conduct in it. This confrontation is embedded in what epistemic logic represents: the truth or the falsity of our perceptual judgments (Figure 11).

Figure 11:

Epistemic logic: confrontation in logical reality through coherent interpreted meanings of three inferences in the quasi-proof of the truth of perceptual judgment.

In our perceptual experience, we intuitively reflect upon its operation to self-control the meaning-coherence of the two perceptual components, the sight and the touch of the eventual object, be it the Peircean immediate object or the Kantian blind object. Thus we can cognize the validity or invalidity of the interpretation in the eventual cognitive operation of proofs.

In connection to the above, epistemic logic can prove the truth of our moral laws to act by knowing the world-nature in which we behave and act, as components of nature. Spinozistically speaking, we can accomplish our free moral imperatives to be embedded in reality and thus accomplish our duties. However, Kant had to find an explanation of how we can accomplish our moral duty in the domain of Nature given the epistemic schism between the domain of pure morality with its a priori categorical imperative of the transcendental subject.

[We said that] reason, when it considers nature theoretically, has to assume the idea that the original basis of nature has unconditional necessity. But when it considers nature practically, it similarly presupposes its own causality as unconditioned (as far as nature is concerned), i.e., its own freedom, since it is conscious of its [own] moral command. Here, however, the objective necessity of the action, in other words, duty, is being opposed to the necessity that the action would have if it were a [mere] event with its basis in nature rather than in freedom (i.e., the causality of reason); and the action that morally is absolutely necessary is regarded as quite contingent physically, i.e., [we see] that what ought necessarily to happen still fails to happen on occasion. It is clear, therefore, that only because of the subjective character of our practical ability do we have to present moral laws as commands (and the actions conforming to them as duties) and does reason express this necessity not by is (i.e., happens) but by ought to be. (CJ: 403)

Indeed, Kant’s problem is how to combine the theoretical understanding of nature and its causality with human causality as unconditioned and free hence, how to combine the causalities of nature and human freedom? It seems that Kant tries to follow Spinoza in the distinction between the causality in nature and the human inner causality as one’s Moral freedom and yet for Kant they operate in different domains to keep human freedom absolute, while the Spinozist conception of human freedom is in Nature and relative to human knowledge of reality and one’s relative power in Nature (Nesher 1999a).

9 Kant, in his late research looking for help in Spinoza’s Realist Epistemology

According to Spinoza, human morality is a component of natural causality, like other components of nature. Hence, the infinite nature includes all of its components with their effectivity, then freedom is only relative to their powers within global nature. We can make the general claim that according to Spinoza the freedom of all modes in nature does not contradict its determinism, but is the self-determination of those natural modes-elements yet are relative in their powers with respect to other modes-components of nature.

This would not be the case if we consider reason, regarding its causality, as being without sensibility (the subjective condition for applying reason to objects in nature), and hence as being a cause in an intelligible world that harmonized throughout with the moral law. For in such a world there would be no difference between obligation and action, between practical law that says what is possible through our doing. It is true that an intelligible world in which everything would be actual just because it is (both good and) possible – and, along with this world, even freedom, its formal condition – is for us a transcendental concept that is inadequate for a constitutive principle for determining an object and its objective reality. Yet [the concept of] freedom serves us as a universal regulative principle because of the (in part sensible) character of our nature and ability, and the same applies to all rational beings connected with the world of sense, in so far as our reason is capable of forming a representation of them. That principle does not objectively determine the character of freedom as a form of causality; rather, and with no less validity than if it did do that, it makes the rule [that we ought] to act according to that idea a command for everyone. (CJ: 403–404; cf. GMM, 4: 462)

We can see how Kant comes close to Spinoza’s conception of freedom as causality in nature as “an intelligible world that harmonized throughout with the moral law. For in such a world there would be no difference between obligation and action, between practical law that says what is possible through our doing.” However, since Kant does not have any theory of truth to prove our representation of reality, and, thus, all that we can conceive in our sensual experience, and thus we cannot know the things in themselves, the noumena or the supersensible, and, therefore, Kant cannot use them as the common background to unite the Transcendental a priori theoretical Understanding and practical Reason with the experiential sensations. This seems to contradict some of the interpreters of Kant’s philosophy who aim to show that there is unity of the transcendental and the empirical components in order to facilitate his moral theory. Nevertheless, it seems that Kant comes closer to Spinoza’s conception of Nature and Freedom (CPuR: B82–88; Guyer 2005).

It is this causality’s determination whose basis is contained, in a way not otherwise explicable, in the intelligible that is thought of when we think freedom (just as in the case of the intelligible that is supersensible substrate of nature). (CJ: 195–196)

The similarity between Spinoza’s conception of Nature and Kant’s conception of God or even the supersensible is that they are used as the frameworks to connect the domain of theoretical knowledge with the practical moral-ethical domain, to enable our explanations of moral conduct in nature-society. About this issue, Guyer suggests his own interpretation of Kant’s discussion of Spinoza in his Opus Postumum (Kant 1786):

Kant’s numerous references to Spinoza in his final writings are only meant to emphasize the difference between his own systematicity of human thought as a product of reflective judgment and what he took to be the dogmatic monistic metaphysics of Spinoza … (Guyer 2005: 278)

The epistemological difficulty is whether Kant, in his later writings, managed to overcome the gulf between the transcendental subject and empirical human beings. Alternatively, Spinoza’s Realist epistemology can explain the unity of the mental and the physical in nature and thus to show that we don’t need to postulate any transcendental a priori assumptions which cannot be proved true to explain human knowledge and ethical conduct (Nesher 1979, 1994b, 1999a). Guyer tries to show that the all-embracing Kantian philosophical system of reality, as based on our reflective judgment, actually holds for him only in aesthetic judgment, which remains subjective. This is in contrast with Kant’s conceptions of the logical judgments in natural sciences and the moral judgment, based on a priori transcendental pure fact of reason as moral concepts and laws, that actually cannot be applied to empirical human conduct.

Legislation through concepts of nature is performed by the understanding and is theoretical. Legislation through concept of freedom is performed by reason and is merely practical. Only in the practical sphere can reason legislate; with regard to theoretical cognition (of nature), all it can do (given the familiarity with laws that it has attained by means of the understanding) is to use given laws to infer consequences from them, which however remain always within nature. But the reverse does not hold: if rules are practical, that does not yet make reason legislative, since they might only be technically practical. (CJ: 174–176; cf. on Spinoza CJ: 453)

The question is whether and how reason can be legislative morally, to make reason practical in human life and not only technically practical? Following the Peircean conception of the three Normative Sciences, Theoretical, Ethical and Aesthetical, it can be shown that all our basic sciences are not only representing reality but are also practical, changing and enhancing it for better life in it (1906, “The basis of pragmaticism in phaneroscopy” in EP 2; Nesher 2007, 2009, 2022). I suggest that Kant, in his final writings, the Opus Postumum, elaborated on the conception of God and Nature-World in connection with Spinoza in order to overcome the gulf between transcendental freedom and practical conduct in his first two Critiques, which he already tried to resolve in his last Critique. However, Kant misunderstood Spinoza’s Realist epistemology which he developed by understanding nature as the infinite plenum in which we know the two attributes, Extension and Thought, and how we can develop our knowledge of particular things in it.

According to Spinoza, human beings are a union of mind and body and thus the dictates of reason of moral ideas and practical conduct of persons in society are two components of behavior. Eventually, by living to develop their essences, they achieve their virtues in moral conduct. As an atheist, and being cautious of attacks from the religious establishment, he identified Nature with God, in contrast with Guyer’s interpretation of Spinoza (Guyer 2005). Contrariwise, Kant uses God to explain his Pure morality based on his conception of Freedom as absolute independence from the causality of nature. Therefore, humans and their morality can be explained only by the idea of God. Kant’s conception of “God and the world” is the background that connects the domain of the theoretical science of the Understanding and the practical moral domain of Reason to explain the connection between human knowledge and ethical life, as he attempted to do earlier with the conception of the supersensible substrate of nature and morality. For example:

Spinoza’s idea of the highest being – of intuiting all supersensible beings in God. Moral-practical reason. Transcendental idealism. Ens summum and ens entium. (OP: 21:12; cf. 21:15, 21:21)

God is not the world-soul. Spinoza’s concept of God and man, according to which the philosopher intuits all things in God, is enthusiastic (conceptus fanaticus).

God and the world. A system of transcendental philosophy, of technical-theoretical and moral-practical reason.

The concept of God is that of the being as the highest cause of world-beings as a person. How the freedom of a world-being is possible cannot be proved directly; it would only be practicable in the concept of God, if he were assumed. (OP: 21:19)

Since we live in empirical reality, we cannot accept the categorical imperatives as the absolute-ideal ethical rules. Rather, we accept ethical rules as relative to the real situation in which we live, so that we will prove its truth in the specific situation and, thus, be able to conduct ourselves accordingly, enhance our lives practically, and live better. This suggested explanation differs from what Kant suggested: “Act only according to that maxim whereby you can, at the same time, will that it should become a universal law” (GMM: 21–55, 55–72), Rather, act according to the universal law as it can become the maxim applicable to the real situation. And here we should note the difference between utilitarianism concerning the enhancement of the happiness of most people, which a la Kant is only a hypothetically good system, from the Kantian absolute moral system based on the ideal categorical imperative. That cannot be materialized, this is so because, for Kant, morality should be absolute, like logic and mathematics, whereas good is similar to our knowledge of theoretical sciences, which is intended for technical-practical conduct in contrast with moral-practical reason (Kelsen 1991: 13–14).

According to Kant, the moral categorical imperative rules are distinguished from laws of justice, and, further, from the hypothetical imperatives of skill-technical rules inferred from our theoretical knowledge of reality. Thus, we arrive at the Realist conception of moral rules, laws of justice, and theoretic technical instructions for life versus Kant’s categorical imperatives of moral conduct, and technical-practical instructions of conduct in empirical reality. The alternative to both hypothetical and categorical systems is the true ethics that considers the life of all, based on the Spinozist conception that persons, by knowing themselves, their essences, and their society can live together affluently and happily. This is an ideal of complete knowledge and sincerity, which, at best, we could find in small communities like the kibbutzim in pioneer-era Israel of the early twentieth century. The central question is, how can we be ethical in the divergent societies we live in and how do we confront the cruelty of some people? The ethical life of people is not only the formulation of ethical imperatives, maxims, rules and laws, but also the structure of society, which includes the interests of its members, both personal and social-collective. This is achieved through people’s knowledge of their own essences and the structuring of common society as close as possible to the kingdom of ends, which allows them to be true to themselves and society, to develop their essential abilities, and to live productively and happily.

Human free will is internal causation versus external causation, which can restrict the subjective will. According to Spinoza, by understanding nature, we can find the laws that enable humans to accomplish, yet relatively, their will to act in Nature (cf. GMM: 432–433).

The subject determines itself (1) by technical-practical reason, (2) by moral-practical reason, and is itself an object of both. The world and God. The first is appearance in space and time. The second according to concepts of reason, that is, a principle of the categorical imperative.

The knowledge of oneself as a person who constitutes himself as a principle and is his own originator.

God and the world are both a maximum. The transcendental ideality of the subject thinking itself makes itself into a person. Its divinity. I am in the highest being. According to Spinoza, I see myself in God who is legislative within me. (OP: 22:53–54)

The question is whether Kant can combine the theoretical reason and practical reason to make moral reason practical by being proved true in sensual experience due to theoretical reason and then practical in real life. In other words, whether he can explain the medium, Nature or God, or metaphorically together, to move from vague metaphysical assertions to “the sources from which certainty therein can be derived, and certain criteria by which it may distinguish the dialectical illusion of pure reason from truth” (from a draft to Reinhold Bernhard Jachmann, January 14, 1800 in Kant 1974 [1800]: 441). We can see that Kant did not understand Spinoza’s conception of Nature, which only for the sake of caution (caute) he identified with God, and hence, Kant considers God and Nature as two different entities, which he can unite together, like Spinoza (OP: 21:34, 59):

And the cosmotheological proposition: “there is a God,” must be honored and obeyed in the moral-practical relation just as much as if it were to be expressed by the highest being, although no proof of it takes place in technical-practical respect, and to believe or even wish for the appearance of such a being would be an enthusiastic delusion – taking ideas as perception.

It can be said without qualification: “there are no gods; there are not worlds,” but rather: “there is one world and there is one God” in reason, as a practically-determining principle.

There is a fact of moral practical reason: the categorical imperative, which commands for nature freedom under laws and through which freedom itself demonstrates the principle of its own possibility; the commanding subject is God.

This commanding being is not outside man as a substance different from man. [It is rather,] the counterpart to the world represented as the complex of all possible beings (their totality), as the counterpart [of God] in space and time, as absolute a priori unity in intuition. Like God (as the supersensible principle which combines the manifold of the world through reason) the world is thought a priori, as absolute unity. These two ideals have practical reality.

A being which includes the whole of all possible sense-objects is the world, (A being in relation to whom all human duties are likewise his commands, is God). (OP: 21:21)

God is the commanding moral categorical imperative within human subjects, who can be naturally freed to direct their lives in the natural world. Thus, moral conduct can be practical in our life, and thus, God inside us and the Nature in which we live allow us to make our morality practical. This, then, is the mode in which Kant comes close to Spinoza to make rational morality practical in reality. Nature is not mechanical and human freedom in nature is relative to the subject’s self-control in reality. Indeed, due to other causes in the World-Nature, the freedom of human beings to accomplish their dictates of reason is relative to the power of other causes compared to the power of action of the human subject itself. As I showed above, in his late philosophy Kant tried to solve the difficulties in his three Critiques by coming close to Spinoza’s realism.

10 Conclusion: can Kant transcend the pure subject’s empty concepts to explain the knowledge of ourselves and of external reality?

In the centuries since the appearance of Kant’s Transcendental writings with their Copernican Revolution against Cartesian Rationalism and Humean Empiricism, this way of thinking has seen a meteoric rise to prominence, yet it cannot solve the basic problems of philosophy. Indeed, most philosophers since have been neo-Kantians of one sort or another, adopting different aspects of his epistemology. We can understand Kant’s concept of ‘transcendental’ as a critique of Descartes’ rational idealism that the only thing one can know is his own subjective thought namely, “I think therefore I exist” (cogito ergo sum), and thus one cannot know the external reality. This is Kant’s basic problem (as he says himself) and the problem of basically all philosophers who did not develop a theory of truth. Kant, in order to overcome Descartes’s subjective idealism, suggested that transcendental idealism makes it possible to go beyond self-thinking, to transcend subjective self-knowledge to reach one’s sensual intuitions of phenomenal objects. This approach combines Humean phenomenal empiricism with Cartesian subjective idealism and stands in contrast to what Kant calls transcendental realism (Kant, CPuR, A367–369), i.e., the knowledge of external reality, of the things in themselves, the noumena. The Kantian endeavor to combine the Cartesian rational idealism with the Humean sensual empiricism remained unsolved: Kant’s solution is his mysterious schematism but he himself admitted that one cannot transcend the empty concepts of the transcendental subject to reach blind sensual objects (Kant 1993 [1798]: 257; Nesher 2022; cf. Hintikka 1972).

Peirce points out that since without perceptual experience there is no meaning to the concepts of the transcendental subject, Kant, as a nominalist, cannot claim to know his own thoughts in order to know his own existence à la Descartes’s cogito. He thus remains a blind fictional rational idealist and clearly cannot transcend his fictional existence even to reach his sensual experience, not to say the noumenal reality. In this way, we can understand why Descartes could not know himself and that all rational idealism, including their formal logic and pure mathematics remain fictions and the Humean sensual experience remains blind. The solution to this deadlock is the Spinozist and Peircean realisms. Beginning with our sensual experience we abductively discover perceptual concepts. These, in turn, are interpreted deductively in our feelings and emotions to synthesize them rationally into the meaningful conceptual thoughts of perceptual judgments, which can be inductively proven to be true representations of ourselves and the external reality together as the Siamese twins (Nesher 2004a).

To sum up, Kantian transcendental idealism cannot transcend idealism to reach sensual intuition in order to present phenomenal experience. The transcendental self thus remains solipsist and the Kantian epistemology cannot work.