Chapter 7 Dualism: Mental and Physical

In: Mind and the Present
Peter Rohs
Search for other papers by Peter Rohs in
Current site
Google Scholar

In an article published in Information Philosophie,1 Tetens asks whether naturalism is “the metaphysical bias of our time.” He emphasizes a “widely disseminated, hegemonic, worldview bias to naturalism” that is hardly questioned anymore. In his radical formulation, it states that everything that exists is fundamentally describable and explainable in the categories of the natural sciences. It is, however, a “stagnating and degenerative research program”; for this reason, it is appropriate to investigate the metaphysical rivals in earnest once again, namely dualism and idealism.

This book has from the very beginning worked on the elaboration and justification of such a “metaphysical rival”—a dualism on the basis of transcendental idealism. I explained which Kantian theses should be employed in a number of problems. A central difference to Kantian theory—confining the form of intuition to inner sense, and there to temporal A-determinations—was already mentioned at the beginning of this book. In Kant, the dualism of phenomena and noumena is an implication of his conception of the forms of intuition; the dualism presented here likewise results from what is now valid as form of intuition. It concerns primarily a dualism of process types—there are processes in which temporal becoming is essentially integrated and others that are independent of it. Since it concerns an intuition form of inner sense or self-consciousness, which relates to the mental event in its totality, the processes of the former kind are mental ones. One of the main theses of Kantian transcendental idealism, that the form of intuition of inner sense is an “immediate formal condition a priori of our souls,”2 remains valid. Resulting from this basic dualism is a dualism of concepts; there are concepts that are dependent on this form of intuition due to their content and others that are only formally so because all concepts are a product of mental processes— A-formed and A-free concepts (Chapter 3). This then establishes a dualism of causality types. Mental causation concerns processes of the former kind, since A-formed concepts are essential for explanations. Natural causality, in contrast, concerns processes that are possible independent of temporal becoming (hence already in the block universe). In explanations according to its schema, A-free concepts must be used exclusively. Finally, it is also valid that mental processes can have only the status of appearances. For Kant, due to his conception of the forms of intuition, the physical and the psychical are only appearances. Based on the modification of this conception, this is only valid for mental processes. A dualism of entities could only be assumed insofar as there can also be intuitive references to singular items in the mental domain. There is no ground for a dualism of independent substances, which is already the case in Kantian theory.

In the following chapters, these theses are to be further elaborated in the context of current discussions about the mind-body problem. I hope to be able to show that transcendental idealism in the form proposed here is in agreement with well-founded empirical research results yet is a good candidate as “metaphysical rival” to the stagnating and degenerative research program of a dogmatic, unrestricted naturalism that is empirically ungrounded.

A non-naturalistic metaphysics is concerned with three tasks. First, the irreducibility of the concepts for the mental must be demonstrated, thus it must be shown that these concepts cannot be traced back to natural science concepts in analytical form. Second, it is to show that the mental is not an ineffective component of reality. The possibility of mental causation is not yet given with the irreducibility of the mental, since it is only a matter of a conceptual relation. A naturalistic position is also the so-called non-reductive materialism. Its advocates grant the irreducibility of the mental but maintain the causal closure of the physical. The mental is, according to this conception, not reducible to the physical—wherein lies the non-reductive side of this materialism. Despite this, we are dealing with a naturalistic position, since there is to be no effect of the mental on physical processes. A simultaneously non-reductive and non-naturalistic metaphysics thus also has to prove that mental processes can be causally relevant for physical ones. This problem will be elaborated in the context of the discussion of the problem of freedom in the next chapter. Third, it must also be shown that such a dualism is compatible with a Darwinistic evolution theory. A critic of naturalism like Thomas Nagel would like to show in his book Mind and Cosmos (2012) “why the materialist neo-Darwinian conception of nature is almost certainly false” (according to the book’s subtitle). The question arises, though, whether a rational critique of naturalism must have this consequence. Darwinism and transcendental idealism should be able to be rendered as compatible. In Chapter 9, I would like to show that this is the case in the version proposed here.

First is the demonstration of the irreducibility of concepts to the mental. The decisive thesis of transcendental idealism to address this question is that the mental has the status of an appearance. It is the result, as stated, of the form of intuition of inner sense being an immediate formal condition a priori for all mental processes. Appearances in the sense of transcendental idealism have a twofold dependency; they are dependent on something that is not appearance, something which is independent of it, as well as a constitution by means of a subjective, epistemic activity, by means of a form of intuition or a synthesis in cognition.

Kant refers to causal dependency on an independent reality in the case of sense perception as affection. The acting forces are things in themselves, thus entities that have no spacetime properties. The question whether this kind of causal effect can be seen as meaningful led to one of the most important and weightiest objections to Kantian theory. For the version presented here, this problem does not arise; the spacetime extended physical objects are what affect us; causal affection through objects is a process that spreads out in space and time. In perceptions, the perceived objects have a causal influence on our sense organs.

Kant also assumes an affection in the case of self-consciousness, but would like it to act purely within the mental. Inner sense represents us to consciousness as we appear to ourselves but not how we are in ourselves, “since we intuit ourselves only as we are internally affected. That which determines the inner sense is the understanding.”3

When viewed in this way, its commonality with sensible affection, which takes place through a physical object, is lost. Affection in self-consciousness should not be understood as a process purely within the subject, just as affection in perception is not. Instead, this inner affection could be interpreted as the causal dependence of the mental on the brain (or the entire organism). Just as a single perception is based on a physical affection, so is the mental as such and in its entirety based on the reality of the brain. This effect can be investigated more precisely with the means of natural science, just as the details of causal affection in perception processes can be investigated more precisely with scientific means. The fundamental dependence as such is obviously in both cases already known, even before all scientific research. Everyone knows that the destruction of the brain (like a bullet in the head) ends the mental processes of the person. This dependency is often practically exploited by persons who have performed presumably little brain research. There is no doubt that the mental is dependent on the processes in the organism in many ways. The dualist has no reason to dispute these obvious dependencies, just as little as he or she could dispute that seeing is based on the influence of photons. This dependency of mental processes on the brain can also be referred to as “affection.”

There is still another side to appearance, one that is constituted through subjective cognitive activities. In the case of the mental, it is a self-constitution. What it is based on has been stated repeatedly: the intuition form of self-consciousness provides its immediate formal condition a priori: the passing present as the necessary basis of being. Mental processes can only exist on the foundation of this self-constitution.

The assumption of such a self-constitution was an important foundation for Kant’s and Fichte’s theories of subjectivity. Kant’s thesis that we also cognize ourselves only as appearance was already mentioned. Fichte even posits self-constitution as a principle at the beginning of his “Doctrine of Science” (“Wissenschaftslehre”), “the I posits itself ” is its first principle. The material conditions for this—the body as the “condition of possibility” of this self-positing—were only “deduced” as the theory progressed. Affection is only viewed as a necessary condition for the primary self-positing. For Kant and Fichte, this self-constitution is not only conditional due to its requiring a material basis; but it is also valid that underlying a sensible-temporal I is an intelligible one that is not appearance and is outside of time. But if the form of intuition is an immediate formal condition a priori for the mental as such, the assumption of an intelligible I is inconsistent. There can then be no “I in itself.” The brain is, according to the view here, like all physical objects, not an appearance. It would still be false to see it as an “I in itself” since it could not be ascribed subjective qualities. Judgments in which A-formed concepts are applied to the brain are meaningless; underlying them is a categorial mistake. This is not an objection to affection as such but to an uncritical way of describing it.

Perspectivism, which is valid for all concepts concerning the mental, is based on self-constitution. The primacy of perspectival world access underlies all cognition of reality since it is connected to intuition; it can, however, be overcome to a certain extent in theoretical experience (cf. Chapter 3). The perspectivism of self-experience is, however, insurmountable, since all access to the mental is “formed” through the form of intuition. One can thus say with Searle that the natural ontology of mental states is a first-person ontology,4 it is thus a perspectival ontology. “Mental states only exist as subjective, first-person phenomena.”5 Von Kutschera likewise emphasizes that expressions for the psychical always have a subjective sense.6 “We could not talk about the psychical at all without expressions with perspectival sense.”7 The basic idea is that a process of becoming real, of becoming present, is an essential character of mental processes.

“Strict natural sciences” should designate those in agreement with physics in view of their conceptual and ontological foundations, which remain in the horizon of the ice block-ontology. A clear boundary for naturalism arises if one interprets naturalism as the thesis that everything real, each process, can be described and explained with the conceptual means of the strict natural sciences. Mental processes could not be discussed in this context.

The irreducibility of the mental is an immediate consequence of the appearance-character. Appearances are not reducible to their underlying non-appearing reality (to “things in themselves”), since the constituting moment contained within them—the dependency on epistemic activities—makes this impossible. Kant speaks occasionally of us “putting something into” appearances. What has been “put into” the appearance can per definition not be explained from the other side. In the case of the mental, this is primarily the dependence on the process of temporal becoming. Mental processes cannot be entirely represented by functions f(x,y,z,t) for this reason.

It should be accepted, similar to perception, that affection is a necessary condition of self-constitution. Without affection there would be no self-constitution, without a brain there would be no form of intuition. Kant would probably also grant this. A dualism in which the mind is assumed to be separable from the body is untenable and is in any case not presupposed in the position presented here. The indispensability of affection, however, should not be understood in such a way that no place for self-constitution remains. This causes something to come about which cannot be achieved by affection for conceptual reasons—something for the description of which A-formed concepts are indispensable, concepts with contents that are dependent on the form of intuition. Despite this, affection remains a necessary condition for everything that only becomes possible through self-constitution. In the block of ice something must be able to emerge to enable it to be “thawed” in certain places.

Phenomenal contents make it necessary to assume certain fixed correlations between the mental and physical. Such relations even had to be presupposed in the parallelistic theories of the seventeenth century. Nowadays a supervenience of the mental over the physical is postulated. Diverse mental states are to continually correspond to diverse physical ones. Such supervenience relations can be defined in precise terms in different ways.8 They concern only simultaneous states and are compatible with mental states having the status of appearances. In any case, concepts cannot be defined for mental states if one only has concepts of the strict natural sciences and supervenience relations at his disposal. Von Kutschera shows in detail that similar proposals in all cases have failed.9 Supervenience relations in all proposed versions are thus compatible with mental states having the status of appearances and owing their existence to self-constitution. It is in any case unclear whether such relations can be found out empirically if their relata are to be described precisely.

A well-reasoned thesis of Kantian theory is that receptivity and spontaneity must be distinguished within the mental. That sensations are given is something other than the relation to concepts and propositions, since these can be seen as products of mental activity (referred to as the understanding in Kant). It is obvious that the dependencies qua affection and qua constitution respectively must be distinguished in both cases. Both dependencies must exist for both; sensations can be traced back to causal affection but possess specific mental qualities; the spontaneity of the understanding provides sense entities, the emergence of which cannot be explained in naturalistic terms yet is bound to a functioning brain, without which there would also have been no spontaneity of the understanding.

In receptivity, mental states are passive in the sense that they are directly explainable through a physical effect. In this case, this is what is meant with the expression “affection.” Self-constitution allows for a domain of mental appearances, where causal relations can be effected and through which the qualities of effected states (the so-called “qualia”) can be determined. The passivity of the involved states, however, is not changed by their subjectivity. The results of affection are predictable. Torturers must be able to know what causes pain, and they usually know this as well. Even an eventual insensibility must have physical causes.

Whereas in receptivity self-constitution provides the global foundation and affection enables explanations of the concrete event, the inverse is true of spontaneous mental processes: Affection provides the global foundation, and the particular is only to be explained mentally. Von Kutschera writes, “There are, of course, necessary neurophysiological conditions of our mental states and processes—one is, e.g., that the entire function of our brain isn’t terminated. According to the thoughts in previous paragraphs, it should however not be assumed that there are sufficient neurological conditions for all mental states. It can be, for instance, that a researcher, regardless of how good his instruments are with which he observes the processes in the brain of Fritz, cannot decide whether Fritz is thinking about Klagenfurt or Graz.”10 Contained in the concept of spontaneity is a certain mental effectivity. Unlike sensations, concepts are not given to us passively, we construct them, we create them. Without mental effectivity there are neither concepts nor propositions, and one can reliably assume that no neurologist ever observed how the brain forms a concept because a concept cannot be an object of empirical observation. Concepts, propositions, numbers, sets, etc., are not spacetime entities which can be enlarged by a microscope and looked at more closely. If the products themselves cannot be observed in this way, then neither can the process of their emergence. The formation of a concept, or even an entire theory, is also not observable, even with the best instruments. The most precise description of all the processes in the brain of Einstein would give us no knowledge of general relativity theory if he had not shared it with us.

Kant refers to the result of such spontaneity as “synthesis.” It is “an act of his self-activity.”11 Kant’s development of this conception will not be dealt with here,12 it is sufficient to keep in mind the relation of synthesis to spontaneity, to “self-activity.” I understand synthesis as the constitutive form of what Frege refers to as “sense,” the sense-shaping form—in the important case of propositions the copula connects the singular and general components of an elementary proposition and thereby allows for the emergence of the proposition (cf. Chapter 5). The relation of the synthesis to the form of intuition is then obvious: the fundamental synthesis is present-tensed, the elementary propositions are present-tensed. Spontaneity and the present are bound to each other, they are inseparable, one does not exist without the other. The primary judgments are temporal judgments with the syntheses “is now,” “was,” and “will be.” Judgments with a timeless copula, typically used in the sciences, are constructs that presuppose this basic synthesis.13 This constitution of constituted senses is a consequence of the temporal structure of constituting. The form of intuition is immediately connected in self-consciousness to spontaneity and hence to the syntheses.

Husserl paid special attention to this form of temporal process. He describes mental spontaneity as a constitution of senses in several passages. The world, as is stated in his Cartesian Meditations, “gets its universal and special sense and acceptance” only through such constitutions.14 These are only possible through time-consciousness: “The fundamental form of this universal synthesis, the form that makes all other syntheses of consciousness possible, is the all-embracing internal consciousness of time.”15 This “fundamental-form-thesis” (how I would like to refer to this passage) concerns the temporal basis of subjective spontaneity: spontaneous mental processes are only possible due to temporal becoming, i.e., formed through the intuition form of self-consciousness; they have no counterpart in the block universe and cannot be grasped with the terminology of the strict natural sciences. In his interpretation of Kant, Heidegger already set out to find a comparable view in the Critique of Pure Reason.

Next to this irreducible temporality is another essential structural moment of spontaneity, its relation to an I-center (Ich-Zentrum). There is no spontaneity without an I, without a subjective mental origin of activity, no “actus of self-activity” without a self. Receptivity can be conceived without such a center, with spontaneity it is not possible. In idealistic theories (of Fichte or Husserl), this nexus is often pointed to. There is no ontology of the first person without a first-person, no perspective without a center of direction of look (Blickrichtung).

Descartes assumed that a mental center would have to correspond to a center in the brain, which he identified as the pineal gland. In the meantime, however, neurologists have found that there is no such “convergence center” in the brain.16 Instead, there is an ensemble of networked neurons. Even if this is the case, it does not mean that spontaneity is possible without an I-center, without an “I think.” It only follows that the self-constitution of the I does not require similar structural components in the affecting brain. Brain and mind do not exist in a relation of replication, of isomorphy. That not every neuron corresponds to a “mental neuron” is in any case obvious. Nor does a physical center have to exist for the mental one. Supervenience also does not require this to be the case. There is thus no “observer in the brain”—an idea that was correctly opposed by Singer.17 Persons observe, but to do this they need not only a brain but also an I-center, without which there could be no senses, no concepts, and no propositions. The I chiefly constitutes itself, “it posits itself,” that is, not without a brain but without an analogous physical convergence-center. There is no “I in itself” in the brain. The centering ensues mentally and under the condition of the form of intuition, not purely physically in the block universe to which the brain belongs, and it can also not be described using the concepts of the strict natural sciences.

Roth views the I (next to the body and the world) as a “construct” of the brain.18 This seems to share a certain similarity to the thesis presented here, namely, that it has the status of an appearance. According to the thesis here, the I constitutes itself; according to Roth, the brain, which belongs to the body and the world, constitutes itself. The differences are obvious. Here, in reference to Kant, a two-sided dependency for appearances is assumed—qua affection of something physical (in the case of the I of the brain), qua mental constitution of epistemic activities (in the case of the I of self-knowledge). Roth assumes only a one-sided dependency, but describes it using mental concepts, “constituting” is a mental activity which is not possible without concepts. The dependence on the brain, which as such cannot be denied, is thus described categorially false, it should actually be understood in concepts of the strict natural sciences. Like in the case of freedom (which will be dealt with later): The concepts which are to be used to explain and describe certain processes are decisive. As soon as one begins using concepts for the mental and does not define them with concepts of the strict natural sciences, one assumes a dualistic position, initially a dualism of concepts. But if these concepts prove to be indispensable for explanations, then one also assumes a dualism of causality types. This dualism has to be seen as decisive insofar as it is based on the assumption that persons can be intentionally effective, thus, that they are actually persons.

One can be certain that a “constructing” process in the brain has never been observed empirically since there can be no images of senses. Most importantly, the assumed synthesis activities leading to the formation of concepts and propositions cannot be immediately ascribed to the brain, although they are also not possible without it. Concepts and propositions exist only for an I with mental spontaneity, they could not exist without an “I think.” In conclusion, there is no I without spontaneity but also no spontaneity without an I.

Since the brain constructs nothing, it also does not construct the world. But with the general constitution thesis it can be assumed that facts, due to their propositional structure, are based on constitution-activities. Facts are neither physical objects nor events. The I has no causal effect on real physical objects (stones or stars) (excluding action), neither as constructing nor in the sense of natural causality.

The I can be considered the mental component of the person. It is not a matter of the dualism of independent entities, since the I’s dependence on the brain is not restricted or eliminated. Just as one can discuss mental spontaneity as such, its origin-center, the I, can also be a theme. Only the person can be viewed as the cause of actual actions, since included in the concept of action is body movement. But mental spontaneity, intentional activity, can also be addressed in this case, and for this purely mental perspective the I is the origin of activity. One could say that the I thinks and the person acts. That a perspective is possible in which the mental is isolated from body processes and considered in itself—the intentionality of the action, the I of the person—is an essential element of dualism. This is why Descartes introduced the dualism of res cogitans and res extensa.19 The philosophy of Husserl also takes up this point. The method of phenomenological reduction involves a systematic analysis of a perspective that isolates the mental. The possibility of such a consideration, however, presents no argument for a real independence. The possibility of this perspective does not contradict the dependence of the mental on the brain. This dependence is, as stated, indubitable, and is reinforced by scientific research. It is not about a substantial independence of the I-center, but that it can be conceived as the initiator of spontaneous activities.

A dualist must therefore assume that a concentrated perspective on the mental is possible in the first person, in which the body as well as the brain are faded out. The natural ontology of mental states is a first-person ontology (Searle), because in the first person exists the perspective on the mental in itself. The mental is separated perspectively as an appearance, not in reality from the physical. In reality, however, as will be shown in the following chapter, it must be valid that it is causally effective in the form of mental causation. Even if the mental only has the status of an appearance, the difference of causal types has to be seen as real. This difference, as stated, is what makes humans into persons, and humans are really persons (with certain restrictions occasionally).

Diachronic identity is essential to the constitution of an I-center. Whoever busies himself over a long period of time and intensively with a problem must be conscious of his identity as he carries out his mental work. An action has to have the same motive in all of its phases, but the initiator, the actor, must also remain the same throughout the course. Belonging to the sense of an action is that I can be unceasingly conscious of the fact that I am the one acting, that I am the one striving to reach a goal. In all actions, even altruistic ones, it is always about me. The care-structure entails that I am also concerned about me. If I purposefully go, for instance, to the courthouse, I want to find myself there soon. This is why the diachronic identity of the I is presupposed.

We usually extend this diachronic identity, which has to exist in shorter as well as longer actions and plans, to our entire life. We make, for instance, persons responsible for their actions from many years ago. We also assume diachronic identity when thinking about our future. Long-term identity cannot be distinguished structurally from short-term identity, which is part of each action. An 80-year-old is identical to the 20-year-old in the same way as the person who goes to the courthouse is identical to the person who arrives there 10 minutes later.

For the structure of this diachronic identity, I would like to propose three theses and justify them where possible: 1. This diachronic identity is a product of self-constitution. 2. It cannot be conceived according to the schema that is valid for the diachronic identity of material things. 3. It must be thought of as realistic, as objectively valid.

The first thesis is closely connected to the idea that the I-center itself has to be seen as constituted. The I is not only the point of departure of each perspective but is also the result of a certain perspective. As stated, it must not correspond to a physical center, and no physical correlate has to be given for diachronic identity. The spontaneous self-positing is not possible without a brain but is possible without a neuronal center. Diachronic identity also presupposes an enduring brain, but as the diachronic identity of an I it is structurally different from all variants of diachronic identity that could exist in material things. Whether all neurons arrive with me when I go to the courthouse, I do not know, and it might not matter to me. One should be able to assume that the network of neurons and the physical states connected to them change continually and do not even remain the same over fractions of seconds.

The existence of a brain without diachronic identity is completely imaginable. In fairytales we read about sorcerers and how they can effortlessly transform themselves into lions, mice, etc. Alberich possesses this ability (in Wagner’s Rheingold). How radical the transformation of the brain is in this case can remain open. This is an aspect of the perspectival possibility to isolate the mental. More importantly: In the traditional idea of the immortality of the soul, one likewise assumed that it was possible without an enduring brain. Even if this thought is opposed by skeptics, there should be no logical contradiction. Kant refutes the traditional proofs for the immortality of the soul, but still grants its possibility. In this formal sense, the diachronic identity of the I is thus thinkable without an enduring brain.

The connection of diachronic identity to the form of intuition is obvious in the case of the care-structure. I am responsible for my past acts and hope for the best for my future. Underlying the diachronic identity of the I is its being present at different points in time on the world line of the body. Diachronic identity depends on this presentness. The I endures because of its transience. This enduring is, however, also then possible if self-constitution and the existence of the form of intuition are impossible without a brain. Similar to the I-center: There is no I without a brain, but there can be phenomena in the I with no counterpart in the brain.

This diachronic identity is also distinguished categorially from that of material objects for this reason. That the developed conception of diachronic identity from Quine, Russell, and others cannot be valid for the I should be apparent. Russell writes, e.g., “The things we call real, like tables and chairs, are systems, series of classes of particulars, and the particulars are the real things…. A table or chair will be a series of classes of particulars, and therefore a logical fiction.”20 In this conception only the elements that also exist in the block universe are taken into consideration, the “particulars,” the momentary events. It thus deals with a form of diachronic identity appropriate for the block universe. This conception entails that material things can be regarded as objects of a higher order, because the real things in accordance with event ontology are concrete events. Events can be lumped together in different ways, through different relations, to higher order objects, what Quine illustrated with the example of “river,” respectively “water.” This form of diachronic identity therefore already contains conventional moments.

Henrich brought attention to how the self-identification of a person occurs diachronically “without any use of criteria of identity.”21 It thus follows that the Quine-Russell model of diachronic identity cannot be appropriate for conceiving the identity of persons. We do not have to verify the existence of certain relations between the events of our Dasein to be certain of our diachronic identity. By contrast, it is unclear how we are to be able to ascertain the presence of such relations if we are not already certain of our identity.

The diachronic identity of material things should also be dubious for the reason that it is normal for parts to be removed and replaced by others—like in the case of the “ship of Theseus,” whose planks over time were replaced completely by new ones. Is the same material thing still present after such changes? At which point in time throughout the gradual change does a new object come into existence? Ultimately, it does not matter how one answers these questions. Because there are no exchangeable parts in the I, this problem does not emerge.

Similar problems can also exist for the bodies of persons. Cells in the body are replaced with new ones. Diachronic identity is secured through I-consciousness, whose existence depends on the body, yet it is able to bring forth a form of identity not found in the body. Diachronic identity of the brain has to be of the Quine-Russell type since it is a material object; diachronic identity of the I cannot be of this type. This distinction exists entirely independently of self-consciousness’ dependency on the brain. There can also be, like in all spontaneous activities, physical disruptions that result in a loss of certain capabilities. This does not change the fact that spontaneity has to be added to affection if mental phenomena shall emerge. It can also not be observed empirically how this specific diachronic identity is to develop from out of the flow of electric currents in the brain.

In earlier publications22 I have drawn on the elaboration of the conception of realistic diachronic identity in the book The View from Inside (Der Blick von Innen) by Martine Nida-Rümelin (2006). She distinguishes between beings capable of consciousness from those who are not, beings with an inner perspective from those with none, and attempts to show that for the former only a realistic interpretation of diachronic identity (or in her words “transtemporal identity”) is possible. A feature of a realistic interpretation is that questions about diachronic identity cannot be answered in a conventional sense but concern objective truth; the answers to identity questions could be true or false. In beings without an inner perspective, by contrast, in material things like stones or ships, identity questions can be answered ad libitum and purely conventionally, without one having to fear making a mistake. Beings with an inner perspective are broadly understood, so that caterpillars and butterflies are included.23

In accordance with the view presented here, it is the I-consciousness that makes necessary a realistic interpretation of the diachronic identity of persons. I-consciousness should be seen as a perfect inner perspective, a perfect “view from the inside.” The question whether less-developed forms of self-feeling (such as in the caterpillar or butterfly) require such an interpretation will remain open here, as well as the question about the mental states of animals. Transcendental idealism should not adhere to a Cartesian dualism between thinking humans and non-thinking animals. It should be conceived in a way that it remains compatible with Darwinism and can make understandable the evolution of the I-subject. I would like to return to these questions in Chapter 9.

Diachronic identity is considered here to be the result of a spontaneous constitution-activity. It thus belongs, like the I itself, to the world of appearance. The corresponding relations do not exist in the in-itself-existing block universe. As emphasized many times, this does not rule out the objective truth of judgments about such given facts. Judgments about appearances can be objectively true—this is self-evident from a Kantian standpoint. This also applies to judgments about the diachronic identity of beings with I-consciousness. In these cases, objectively valid judgments that rely on appearances are thus possible, whereas corresponding judgments about beings that are not appearances are not objectively valid and can only be decided conventionally.

Nida-Rümelin shows that the existence of this identity is an irreducible fact that cannot be understood through identity-neutral describable relations, psychical or physical, between events at different points in time.24 What has to be presupposed according to my view, however, is the form of intuition, without which there is no self-consciousness. She formulates her theses about “transtemporal property ascriptions, transtemporal self-ascriptions, transtemporal identifications”25 using the variable t—a variable for numbers that serve as time coordinates (dates, times, etc.). In other passages, she also uses A-determinations.26 Only this manner of expression appears to me to be appropriate. That diachronic identity is dependent on A-determinations is a consequence of their being the form of intuition of self-consciousness, so that there is no “view from inside” along the A-determinations. Also, phenomenally-speaking, it appears to me to be important that realistic diachronic identity is not possible without continual presentness. In the short-term version—which is required for each longer contemplation—this is evident. In the course of my thinking I must be present in all phases as the same person.

Höffe sees the “main ideas” of the Kantian “epistemic revolution” in the theorem “objectivity through subjectivity.”27 “Objectivity is owing to the cognizing subject.”28 I prefer to speak of “intersubjectivity through subjectivity.” It deals with the property through which senses distinguish themselves from representations. It is owing to the representing subject, who together with the representations, which have a subjective status29 and are “parts or modus of the single soul,” also bring forth senses that have an intersubjective status and can no longer be ascribed to a single soul. The spacetime extended things and events, in opposition, exist independently of all “epistemic activities.” Apart from the causal interaction connected to affection (which is important epistemically on the level of elementary particles, since these objects are influenced by being observed), the cognitive subject has no influence on these objects. Of central importance for cognition is what does not appear in spacetime—universals and propositions, as well as numbers and sets. That concepts and judgments are products of “epistemic activities” is a well-known Kantian view. They are likewise not “part or modus” of individual souls. I see the “main thesis of the Kantian epistemic revolution” in the thesis that mental spontaneity and only it is able to bring such things forth. Without mental spontaneity there are no senses and no intersubjectivity. In the already mentioned letter to Beck from July 7, 1794, Kant writes accordingly, “But we can only understand and communicate to others what we ourselves can produce.”30 Communicability is, as referred to in a later passage, the result of a “composition”; without it there would only be a non-communicable feeling in us. How noises are conventionally ascribed to senses is clarified in Chapter 4 in light of the semantic theories of Meggle and von Kutschera. The relation of senses to spacetime reality is likewise dealt with in Chapters 4 and 5. Judgments are related to reality through truth, singular senses through the intuitive reference to single objects.

To make these activities understandable Kant uses expressions like “consciousness in general”31 and differentiates whether a synthesis “arises merely relative to the subject or in the consciousness in general.” In the first case, the arising judgment is “merely subjective,” in the other objective. I assume, in opposition, that no alternative exists here but that each judgment belongs, on the one hand, to the epistemic state of a single person and, on the other, contains an intersubjective sense. This has nothing to do with the “necessity” of a unification. For Kant, the sense-constituting activities are closely connected with the ability to obtain cognition a priori. Exactly these cognitions are characterized by their “necessity and universality,”32 although they cannot be based on something receptively given. This and only this, what we ourselves put into the things,33 is thus discernible.

In my view, however, there is no close connection between them. That concepts are grounded in the “spontaneity of thinking”34 would have to be the case even if there were no synthetic judgments a priori, and not only the concepts that could appear in such judgments are products of spontaneous activities. The ability of conceptual thinking is more basic than the ability to cognize a priori, since it concerns all judgments, everything with the status of a sense. For this reason, it has nothing to do with necessity or universality. Both theses also underlie diverse states of affairs. That senses cannot be given receptively is because they cannot appear as links in natural causal chains due to their ontological status. It should be reasoned that synthetic judgments a priori exist because without them certain experiences would not be possible.

The decisive subjective activity concerns the bringing forth of senses, and I see it as certain that all the given moments—that there is mental spontaneity that proceeds from an I-center, that belonging to this I-center is a realistic diachronic identity and its existence underlies the process of temporal becoming—are necessary for it. We are dealing with a group of related structural moments, all of which must be viewed as indispensable for a conceptual, cognitive being. That they are all not possible without a brain has been noted several times. But epistemological questions can be discussed—at least insofar as they do not involve the specific activities of the sense organs—from a perspective that isolates the mental. This perspective also underlies Kantian theory, which is written consistently in a purely mental style.

Kant uses this basic ability as an occasion to suggest a further differentiation of the I, unrelated to the assumption of different faculties that had already been ascribed certain activities. The imagination is to be responsible for schemata, the understanding for concepts and judgments, reason for inferences, etc. He sees the question whether certain inferences can be traced back to the understanding or reason as meaningful.35 Also, for experience and its systematization, both faculties are to perform different functions. One should note that this form of expression should not be taken too seriously. What is essential for spontaneity is independent of it. The sense-constituting activities can be uniformly ascribed to the I and its spontaneity.

Inside the I is also further differentiated. “Consciousness in general” was already discussed. In the first version of the “Transcendental Deduction,” the empirical and forever variable consciousness of oneself is distinguished from the pure, original unchanging consciousness.36 This is similar in the second version: here, Kant distinguishes between the empirical unity of consciousness and the original unity, which alone is objectively valid.37 It looks as if the distinction between Frege’s second and third realm should be projected back into the I: changeable for the psychical, unchangeable for the senses. In Husserl, similar distinctions can be found in the I.38 Therefore, it seems that in addition to the foundational perspectival isolation of the mental I-center, even higher-level abstractions can be carried out in order to make available different starting points for different functions. In my opinion, only the distinction between receptivity and spontaneity appears to be indispensable and objectively justifiable, as well as the data of structural moments of spontaneity. Further differentiations should be dispensable; they merely facilitate expression.

The version of an anti-naturalistic metaphysics proposed here, which is to satisfy the concerns and demands of Tetens, is based largely on the dualistic idealism of Kantian transcendental philosophy. It distinguishes itself from Kantian theory, as mentioned several times, insofar as the thesis of transcendental ideality of space and time is considerably restricted. Only temporal A-determinations are to be valid as form of intuition of self-consciousness. This involves the elimination of each intelligible component of cognitive and acting beings. Despite this, especially through the assumption of mental spontaneity, a boundary shall be formed that cannot be overstepped by naturalistic brain research.

A completely different but likewise Kantian-based answer to brain research is presented by Höffe in his article “What Would Kant Say to Brain Researchers?” (“Der entlarvte Ruck—Was sagt Kant den Gehirnforschern?”).39 I would like to briefly clarify why this answer appears to me to be inadequate. To conceive of freedom, Höffe (with Kant) appeals to an “outside of experience,”40 thus presupposing the validity of the Kantian theory of space and time in its original version. Only because of it do we have something intelligible that transcends experience and can intervene in free actions. Kant himself repeats matter-of-factly that without the assumption of this ideality, “freedom cannot be saved.”41 However, brain researchers have no reason to accept these premises, and Höffe doesn’t provide any. The considerations presented here come closer to empirical research, since they only make use of the ideality of temporal A-determinations.

What ultimately concerns freedom, as Höffe claims, is that there is an action with knowledge.42 This, however, presupposes mental causation, which is a very conflicting topic at the moment. Interactionism has been considered untenable many times (already since the successors of Descartes). Höffe does not argue for it, and he also does not refer to the arguments Kant made to justify it. These arguments—which are indeed hardly convincing—can be found in the framework of the refutation of the proofs for the immortality of the soul, the “paralogisms of the doctrine of the soul,” although they hardly have anything to do with this refutation. Kant formulated these differently in both editions of the Critique of Pure Reason. In the first version,43 it is to be shown that the material and the mental, since both are only appearances, exist in the same way only in our souls. Since both cases deal with representations that should not be “hypostatized” (Kant uses this expression multiple times) as external realities, their union is easy to understand. In the second edition, it is stated that the seeming heterogeneity of soul and material could disappear in what as thing in itself underlies both.44 Because of the uncognizability of things in themselves, one cannot know how they are constituted. Kant was in any case convinced he could refute “soulless materialism” with this theory.45 The anti-naturalistic tendency of his theory is, however, not contestable.

The arguments introduced to address how the relation between mind and body is to be understood and how an interactionism between them is to be possible are unsatisfactory. The first has the consequence that the thesis—that appearances must count as representations of the subject46—has to be understood literally. Such an idealism is, however, unacceptable. In the second thesis, because of the unknowability of things in themselves, we obtain ultimately no argument for the possibility of mental causation. It is only stated that—since everything is possible for things in themselves because of their unknowability—mental causation is not impossible there. But this objection has no force against brain researchers. Both arguments use, moreover, the full scope of the ideality of space and time. Brain researchers would hardly follow.

In the following chapter, I would like to show that mental causation and freedom are defendable with the means presupposed here, thus for the reason alone that the form of intuition of self-consciousness is an “immediate formal condition a priori” of all mental processes. The ban on “making thoughts into things and hypostatizing them” is not needed.47


2013, 3.


KrV B 50.


KrV B 152.


1992, 16.


Ibid., 70.


2009, 153.


Ibid., 162f.; trans. RW.


Cf., e.g., von Kutschera 1993, 26f. and 2009, 142f.


1993, 1f.


2009, 169f.; trans. RW.


KrV B 130.


Cf. Hoppe 1983.


Cf. Bieri 1972, 54, 65, 97.


1988, 21.


Ibid., 49; similar passages can be found on pgs. 64 and 75.


E.g., Singer 2002, 96, 144, 148, among others.


Ibid., 144f.


2003, 48, 189, among others.


6. Med. § 9.


1972, 134.


1979, 177; trans. RW.


E.g., Rohs 2013, 119.


2006, 31.


E.g., ibid., 326.


Ibid., 171; trans. RW.


E.g., 180ff.


2004, 42ff.


Ibid., 47; trans. RW.


In Frege’s words, 1990, 146.


AA 11, 515.


Prol. § 20 and 22.


KrV B 3.




KrV B 93.


KrV B 359.


KrV A 107.


§ 16 and 18.


Cf. the article from Katharina Keßler about the “I” in Gander 2010.


2004b, 177–182; trans. RW.


Ibid., 179.


KpV AA 5, 101.


2004b, 180.


KrV A 384–396.


KrV B 427.


KrV A 357, B 419 and 421, Prol. § 60.


KrV A 389.


KrV A 395.

  • Collapse
  • Expand