CHAPTER FOUR. A NEW VISION OF THE MIND/BODY PROBLEM: THE INNER SENSE THESIS
This chapter is divided into four sections. In the first section, I survey the wreckage of Kant's early metaphysics. I discuss two conclusions that Kant drew in 1766: that there was a need to develop a general "critical method" that avoided both dogmatism and skepticism and that Kant must find some way of mitigating or at least accommodating his own skepticism about understanding primary forces. I focus on how these broad questions connected with the two problems that plagued Kant's earlier attempt to understand mind/body connectedness, the inconsistency in Kant's rational psychology and Kant's inability to prove that souls do not possess the same material nature as physical monads.
The text of this chapter is the Metaphysik L1 lectures, which were based on lectures on metaphysics that Kant gave in the mid-1770s. In the second section, I discuss Kant's lecture on the "Concept of the World." The major difference between Kant's discussion here and his position in 1747 was that he taught that ours is the only actual world because one God could not create a plurality of worlds. Kant's discussion of the form or schema of our world did not diverge significantly from the position he developed in Living Forces and the New Elucidation.
In the third section, I discuss Kant's account of embodied cognition in the Metaphysik L1 lectures. I focus on three of Kant's doctrines, which I call the community thesis, the constitution thesis, and the embodiment thesis. According to the community thesis, the soul and body constitute an especially tight community: my body is the sole conduit for my soul in the sense that my soul is in immediate relation only to my body, and it is in relation to other things only insofar as those things are in relation to my body. This view was enshrined in the embodiment thesis, which stated that there is no mental action where "the body is not come into play" (28:259). As he did in the Appendix to the Universal Natural History, in the Metaphysik L1 lectures Kant maintained the "constitution thesis," which stated that the specific constitution of the body affects the constitution of the soul.
I conclude that Kant's account of embodied cognition in the Metaphysik L1 lectures differed significantly from the account he defended in 1755. Kant asked "from which side is the most to be derived, from the body or from the soul?" (28:261). Whereas in 1755 he took himself to possess strong reasons for thinking that the body contributes more to cognition, in the mid-1770s he taught that "we can say nothing about this" (28:261).
In the fourth section of this chapter, I begin to explore why Kant's views about the mind/body connection, and the role of the body in cognition, had shifted so dramatically by the mid-1770s. I argue that a key reason was Kant's doctrine that the soul is an object of inner sense that cannot be "cognized through materiality" and that possesses a virtual presence in space and not a local presence. I discuss how Kant connected this inner sense thesis to the impenetrability problem in his rational psychology, to the problem of proving that souls do not have the same material nature as physical monads, to a new understanding of the mind/body problem, and to the troubling issue of the soul's location in space. Among the topics I explore are whether Kant thought that the inner sense thesis was sufficient to prove souls' immateriality (I conclude that Kant did not think that it was) and whether he conflated epistemic claims like "the soul cannot be cognized as X" with ontological claims like "the soul is not X" (I conclude that he sometimes did this, although he was also aware of the problem and took some care to avoid it).
4.1 The wreckage of Kant's early metaphysics
In this section, I discuss Kant's estimation of the prospects for metaphysics at the time he published the Dreams of a Spirit-Seer. Section 4.1.1 discusses several general issues that Kant raised, including the general conclusion of that work that he must seek out a method of metaphysics that avoided both skeptical empiricism and dogmatic rationalism. In sections 4.1.2 and 4.1.3, I discuss the two major problems with Kant's early metaphysics, the inconsistency in his rational psychology and his inability to prove that souls do not have the same material nature as physical monads.
4.1.1 The prospects for metaphysics in 1766
In the last chapter of Dreams of a Spirit-Seer, as in the first, Kant reflected on the status of metaphysics. There was an interesting difference in the conclusions Kant drew. Initially, Kant was ambivalent: he started the first chapter with dour sentiments about the possibility of creating a science of metaphysics, but he ended that chapter by concluding that metaphysical inquiries lead to "a tangled metaphysical knot, which can be either untied or cut as one pleases" (2:319). He ultimately found neither attitude satisfactory, concluding that a difficult middle route must be charted between empirically minded ideals that lead philosophers to forsake fruitless metaphysical fantasies and the speculative enthusiasms that give rise to them. In the Practical Conclusion, Kant expressed hope that it was possible to avoid the extremes of empirical skepticism and speculative fancy.
Dreams of a Spirit-Seer left Kant with two conclusions that were crucial for his philosophical development. First, in 1766 Kant had set his attention on employing a general "critical method" of setting limits to philosophical argumentation—the method that he hoped would avoid both dogmatism and skepticism. Although there exist traces of this theme in earlier works, it was only in Dreams of a Spirit-Seer that Kant recognized that perfecting philosophical method would require a sustained inquiry into the limits of reason. The second significant conclusion was that this project required coming to grips with Kant's own skepticism about understanding primary forces, which, I have demonstrated, was not the same as Hume's skepticism about causation.
A thorough examination of Kant's work on these topics is impossible in this study. I am interested in understanding how elements of these larger interests intersected with Kant's attempts to understand the connection between the mind and the body. In this chapter, I discuss Kant's changing understanding of mind/body connectedness in an early set of the Lectures on Metaphysics, the Metaphysik L1, which dates from the mid-1770s. Before discussing this text, it will be useful to recapitulate the problems that undermined Kant's earliest solution to the mind/body problem.
4.1.2 The first problem: an inconsistency in Kant's rational psychology
The first problem was an inconsistency in Kant's rational psychology: Kant asserted that my soul fully penetrates my body, and yet his only account of how souls could be present in space attributed to them impenetrability. If my soul is impenetrable (i.e., possesses a repulsive force), however, it is impossible for my soul fully to penetrate my body. This would imply that two impenetrable things occupy exactly the same space at exactly the same time, a notion that Kant had dismissed in Living Forces as a "metaphysical inconsistency" (§14; 1:27).
By 1770, Kant used the notion of virtual presence, which allowed him to avoid this contradiction. He held that our soul has a virtual but not an actual presence in space: the soul can have effects throughout and near the body without having an actual presence in space. The idea that the soul can immediately act in a place where it is not was not original to Kant, but I show in section 4.4.5 below that Kant's use of this idea was important for the transition to the critical philosophy.
4.1.3 The second problem: an inability to distinguish simple souls and physical monads
Kant's explanation of the schema of our world, which he developed in Living Forces and the New Elucidation, combined with the argument in the Physical Monadology that the presence of attractive forces requires the presence of repulsive forces, implied that things without a repulsive force could neither be a part of nor act in our world. He faced a dilemma: if souls are in our world, they possess repulsion and thus impenetrability, which generates the contradiction in his rational psychology; however, if souls do not possess repulsion and impenetrability, then they can neither exist nor act in the same world as our bodies.
By 1766, Kant saw that there was an additional problem: he came to believe that philosophy was incapable of decisively proving whether or not souls possessed repulsion. In particular, he believed that philosophy could not motivate metaphysical dualism because it could not prove that souls did not have the same material natures as physical monads. The Lectures on Metaphysics show that, as Kant struggled to refute materialism, he came to question and reject the assumption that a soul is a substance. This view, of course, led to Kant's famous conclusion in the Paralogisms section of the Critique of Pure Reason that assuming the soul's substantiality generates pernicious metaphysical supreptions.
4.1.4 A solution not taken
According to the divine schema of our world, our world is such that spatial action requires the exertion of both attractive and repulsive forces. However, if souls have repulsion, they are impenetrable and to claim that souls fully penetrate their bodies would generate a contradiction. Interestingly, Kant did not question the notion of our world's schema that he developed in Living Forces and the New Elucidation. As I show in the next section, Kant's lectures on rational cosmology in the mid-1770s—ten years after he become aware of the fundamental problems—still embraced this earlier view.
4.2 Rational cosmology in the Metaphysik L1
In this section, I evaluate Kant's discussion of the concept of the world in the Metaphysik L1's Rational Cosmology. I demonstrate that Kant retained several key ideas from his earlier pre-critical cosmology, including the idea that what makes a world a whole is the reciprocal interaction of the things in it, the idea that a world's form or schema determines both a world's principles of interaction and the nature of its spatiality. In contrast to in his earlier works, in the Metaphysik L1 lectures, Kant taught that it is probable that ours is the only actual world, for a single God could not create a plurality of worlds. Kant held that there could be a plurality of actual worlds if there were a plurality of gods, but he dismissed this possibility.
4.2.1 The unity of the world
The Metaphysik L1 lectures were based on lectures Kant gave in the mid-1770s. Like all his metaphysics lectures, the Metaphysik L1 lecture address topics from Baumgarten's Metaphysics. The lectures were divided into sections on ontology, cosmology, psychology, and theology. The most important texts for this study are those parts of the rational and empirical psychology that addressed the connection between the mind and the body, although parts of the rational cosmology are also important.
The section in the Rational Cosmology titled "Concept of the World" (28:195-197) contained an explanation of the notion of world that was extremely close to that given in Living Forces §§7-8. The world was defined as a whole that is not a part of anything else (28:195), and what makes the world a whole was "the reciprocal connections and actions"—or interaction (commercium)—of the substances in it (28:196). It is possible that ours is not the only world, for it may be the case that a substance does not interact at all, in which case it would form a solitary world "in and for itself," or that several substances interact with each other but not with any of the substances in our world, thus forming a separate world of their own (28:196). Each world contains a "form," upon which the possibility of the reciprocal interactions of their substances rests. This form specifies "the connection of substances that stand in interaction" and "is the essential condition of the world" (28:196). Kant taught that "the mere existence of substances…does not constitute an interaction, rather to the existence of substances another ground must be added through which an interaction arises" (28:212), a view that he endorsed in 1747. The notes also indicate that Kant retained another key pre-critical idea, namely that:
[T]o exist in space is not merely to exist, rather to exist in space already means: to be in community; for space is a phenomenon of the general connection of the world. (28:213).
Since the existence of space presupposes God's schema or form of the world, he taught that "space is the phenomenon of the divine presence" (28:214).
4.2.2 Our world is the only actual world
The major difference between this position and that of 1747 is that Kant was reported as teaching that ours is the only actual world because one God could not create a plurality of worlds. Although this did not follow from the mere definition of our world, Kant maintained that the dependence of every finite substance on God entailed that all finite substances "are connected and all together constitute a whole". Thus if it was accepted that God is the "communal cause" of all finite substances, then there must be one divine schema or form in virtue of which every substance is connected. It would follow that although many worlds and types of space are possible, only one world exists.
It is unclear whether this difference was enough to make Kant skeptical about his earlier vision of "the highest enterprise which a finite understanding could undertake in the field of geometry," namely a study of "all the possible kinds of space" that could exist under various divine forms or schemas (Living Forces §10; 1:24-25). The notes contained one concession toward Kant's former view that there can exist worlds with different spatiality. Later in the Rational Cosmology, the possibility was raised that two divine beings might have created two separate worlds between which "no relations would be possible," but this was dismissed on the grounds that "there cannot be two Gods" (28:212).
4.3 Embodied Cognition in Metaphysik L1
In this section, I evaluate Kant's views of the role of the body in cognition in the Metaphysik L1's Empirical Psychology. After raising some general points in section 4.3.1 about the types of mind/body interaction on which Kant lectured, in section 4.3.2 I discuss three specific theses, the community thesis, the constitution thesis, and the embodiment thesis. In earlier writings, Kant had maintained that every substance in our world interacts with every other substance via an attractive force. In the Metaphysik L1 lectures, however, he taught that the only object with which a soul was in immediate relation was its own body. This "conduit thesis," according to which the body is the sole conduit for the soul, was the basis of a new understanding of mind/body interaction.
4.3.1 Overview: the connection between body and soul
In the large section on Psychology (28:221-301), Kant was recorded as affirming real interaction between the soul and body. He also put forward a modified version of what I have called his embodied cognition of 1755. The Empirical Psychology section referred to several varieties of mind-body interaction. The mind acts on the body, for example, when its anger causes physical illness, when its intentions and passions cause voluntary and involuntary movement, and when its representations "set the whole body into motion" (28:260). Conversely, the body greatly affects the mind: the lectures recorded Kant's belief that "the constitution and also the state of the mind rests on the constitution and state of the body" (28:260). Although this view seems consistent with that of the Appendix to the Universal Natural History, the answer to a question Kant posed in Metaphysik L1 —"from which side is the most to be derived, from the body or from the soul"—shows that, by the mid 1770s, Kant's views had changed. In the Universal Natural History, Kant clearly held that the most was derived from the body. In the Metaphysik L1 lectures, Kant was agnostic about this question.
The Rational Psychology section recorded Kant's understanding of the metaphysical nature of the connection between body and soul. Kant lectured on whether the soul possesses impenetrability, on where and whether it was present in space, and what sort of cognition it could possess before and after its connection with a body. These lectures revealed Kant's strategy for dealing with the issues that crippled his metaphysical system of the 1740s and 1750s. Of particular importance was a new characterization of the contrast between the mind and the body: "the soul is an object of inner sense, and the body is an object of outer sense" (28:279), a view that I call the inner sense thesis.
4.3.2 Three theses from the Empirical Psychology
The Empirical Psychology section of the Metaphysik L1 was divided into three main sections: the existence of the soul, the faculties of the soul, and the interaction between body and soul. This last section consisted of five scant pages. In all versions of Kant's lectures, this section corresponded only loosely to the equivalent section of Baumgarten's text. Kant's discussion of mind/body interaction covered three main topics, which I call the community thesis, the constitution thesis, and the embodiment thesis:
Community Thesis: The soul and body constitute a community in the sense that:
1. The soul and body constitute a genuine unity;
2. Alterations of the body "are at the same time" alterations of the soul; and
3. Alterations of the soul are at the same time alterations of the body (28:259).
Constitution Thesis:
4. The state and constitution of the soul correspond to the state and constitution of the body (28:260).
Embodiment thesis:
5. There is no mental action where "the body is not to come into play" (28:259).
According to the community thesis, the connection between the soul and the body is especially intimate: they constitute a community and form a genuine unity. Kant held that the relation between the mind and the body was tighter than that between two bodies. Bodies have independent relations to each other: my shoe and the planet Mercury are related in virtue of the gravitational attraction each impresses on the other, my shoe is likewise related to the planet Venus, as are the planets Mercury and Venus to each other. However, my body and my soul are related differently: my body is the sole conduit through which my soul relates to other things, for my soul is in relation to other things only insofar as those things are in relation to my body. In the mid-1770s, Kant taught that my soul is in immediate relation only to my body, and that it has no direct or unmediated connection to anything else. Thus, according to Kant's community thesis, the relation of my soul to my body is not just an example of the kind of community that exists between my body and other things. There is a special community between my body and my soul because, first, other things relate to my soul only in virtue of their relation to my body and, second, my soul relates to other things only through my body. This was a major departure from Living Forces, where Kant held that my soul could be in direct community with other things in the world.
As he did in the Appendix to the Universal Natural History, Kant held in the Metaphysik L1 lectures that a special feature of the mind/body community was that the constitution of the body affects the constitution and operations of the soul. Despite his continued interest in the body's role in cognition, I will show that Kant's constitution thesis of the 1770s represented a significant step away from the embodied cognition he espoused two decades earlier. In the mid-1770s, Kant was still committed to a dualistic metaphysics according to which the material body "comes into play" in every mental action, but, as my discussion of the embodiment thesis demonstrates, he had not yet found a proof that souls are immaterial simples and not physical monads.
4.3.3 The community thesis
The opening passages of the Empirical Psychology eschewed the questions about the meaning or intelligibility of the term 'spirit' that were so prominent in the Dreams of a Spirit-Seer. The notes discussed a specific question about a specific kind of spirit, "the soul of a human being." The question was: In what sense does the soul "stand in connection with the body" (28:259)? A soul stands in a different type of connection with its body than it does to other objects, for together the soul and body constitute a community:
When we consider the soul of a human being, we regard it not merely as intelligence, but rather when it stands in connection with the body as soul of a human being. But it is not merely in connection, but rather also in community, for we can also stand in connection with other bodies, e.g., with our children, but that is no community. A community is a connection where the soul constitutes a unity with the body, where alterations of the body are at the same time alterations of the soul, and alterations of the soul at the same time alterations of the body. (28:259)
The Rational Cosmology section recorded Kant's views that "to exist in space already means to be in a community" (28:213). Indeed, to each of the three characteristics of body/soul connection cited in this passage there exists a corresponding connection between bodies, which stand in connection (Kant took the law of universal gravitation to entail that every body "stands in connection with" every other body), undergo change reciprocally (his understanding of Newton's third law of motion implied that change among bodies is reciprocal: in every instance where A acts on B, B acts on A), and coexist in a world that is a genuine unity (Kant argued that our world constitutes a genuine unity just because its divine schema entails that the bodies in it are connected in this manner).
Is the situation of souls any different from this? If souls possessed essential repulsive and attractive forces, they would be part of this same world community. However, this passage from the Metaphysik L1 suggested that Kant believed that a body and its soul formed a special community: my soul is specially connected to my body. Although Kant often used the word "community" to refer to a causal connection, the community thesis in the Metaphysik L1 lectures appealed to a stronger sense of community that was not limited to causal connection only. First, my body and my soul stand in a connection that is more thoroughgoing than the physical connection that obtains between bodies, for the soul's mental events have physical effects on the body and the body's physical effects have mental effects on the soul. Kant taught that this connection is not explainable in terms of physical forces of attraction and repulsion, which have physical affects only. Second, Kant's claim that my body and my soul constitute a genuine unity had specific content beyond any general claim about the world's unity. For Kant, our world constituted a genuine unity, and all the things in it form a certain sort of community. Any two things in this world are connected in the ways I've described, for example my shoe and the planet Mercury, but as this examples shows it is certainly not the case that every pair of things in the world is itself a genuine unity. Kant's position in 1755 was that one's body and one's soul are connected in a manner that makes them a genuine unity, in contrast to my shoe and Mercury. Specifically, as I explained above, Kant held that the body is the sole conduit for the soul's relation to other things, for "nothing can take place in the soul where the body is not come into play" (28:259).
Kant admitted that he did not comprehend the ultimate source and metaphysical nature of this connection. Nonetheless, he concluded that the connection between body and soul cannot be explained via attractive and repulsive forces, because this would not explain the special connection between our immaterial minds and our material bodies. If the soul were related to the body via attractive and repulsive forces, then it would, in contradiction to Kant's new account of mind/body community, also be immediately related by attraction and repulsion to the other objects in the world. This would contradict what I have called the conduit thesis, which held that:
No alterations happen in the mind that do not correspond with alterations of the body. Further, not only does the alteration correspond, but also the constitution of the mind with the constitution of the body. As for the correspondence of the alterations, nothing can take place in the soul where the body is not to come into play. (28:259)
The body comes into play in all cognition because it is the conduit for all thought. As Kant put it, "thinking concerns things that affect my body" (28:259).
The second sentence of this passage presented Kant's doctrine that the constitution of the body affects the constitution of the soul. Kant's constitution thesis of the mid-1770s is the topic of the next section.
4.3.4 The constitution thesis
In the Appendix to the Universal Natural History, Kant argued that "the body is truly indispensable for thinking" in the strong sense that every aspect of cognition is "wholly dependent on the properties of that matter to which the Creator joined [the soul]" (2:355). On the surface, the Metaphysik L1 lecture notes suggested that Kant retained this view some twenty years later. The empirical psychology was peppered with claims like "the brain is the condition of thinking" (28:259-60), "the corporeal constitution is the cause of the character and the temperament of the mind" (28:260), and even "the constitution and also the state of the mind rests on the constitution and state of the body" (28:260). This appearance was misleading, however, because each of these claims was presented in a muted, qualified form when compared to Kant's views in 1755.
To be sure, most of the textual evidence for this interpretive claim is weak: Kant's discussion of the constitution thesis in the Metaphysik L1 contained numerous omissions and changes of emphasis, differences that do little more than raise the question of whether he no longer accepted the position he defended in the Universal Natural History. I address the strongest evidence that there was a significant change of view, Kant's answer to the question "from which side is the most to be derived, from the body or from the soul," when I discuss the embodiment thesis of the mid-1770s in section 4.3.5.
The following passage was typical of how Kant presented the correspondence thesis in the Metaphysik L1. In the mid-1770s, Kant taught:
[T]he body again affects the mind through its corporeal constitution. This corporeal constitution is the cause of the character and the temperament of the mind. The sort of temperament a human being has depends heavily on the body; the head as well, even the powers of the mind, appear to depend considerably on the body. So the liveliness of one's understanding and wit is seen already in the eyes, and from another stupidity beams from the forehead…. (28:260)
In exactly what sense did Kant believe that "even the powers of the mind appear to depend considerably on the body"? In 1755, Kant asserted that every mental capacity, and therefore the constitution of the mind in its entirety, was determined by our specific corporeal nature. The position sketched in the Metaphysik L1 was much less comprehensive, and was asserted with much less authority: Kant taught that it merely "appears" that some mental powers depend not completely but only "considerably" on the body. In the Appendix to the Universal Natural History, Kant gave numerous examples of specific cognitive powers (reflection, comparison, representation) for which the body is "indispensable". In this lecture, however, the examples did not refer to specific cognitive powers and seemed to amount to nothing more than quite general claims that one's mental faculties have an affect on the demeanor or shape of the body: a vivacious wit shines through the eyes, whereas a sloped forehead is the mark of stupidity. Although this sort of omission does not prove that Kant's views were incompatible with his account of embodied cognition in the 1750s, they do highlight the question of whether Kant's views had changed.
I believe that, in the mid-1770s, Kant put much more of an emphasis on the soul's own powers. This caused him to adopt a nearly opposite view of the health of the soul, for he no longer believed that the health of the soul depended on the health of the body. Whereas before he had argued that high-quality cognition presupposes a healthily active body, he now taught that the activity of the soul placed the body's health in jeopardy, for "the more active the soul is, the more worn out is the body" (28:259).
There is yet another significant difference between the views expressed in this lecture and those of the Appendix to the Universal Natural History. As extravagant as Kant's earlier speculations were, in 1755 he possessed a fairly specific and systematic account of the role of the body in cognition. The claims in the Metaphysik L1 were of an entirely different order. There is no reason to think that Kant taught that bright eyes cause intelligence or ugly foreheads cause stupidity. Kant's examples suggested that nothing more than an unsophisticated and unimportant pseudo-phrenology lay behind his claims about the influence of the body on the soul. Completely lacking was any systematic explanation of the body's influence on cognition, specific claims about bodily influence, and any thoroughgoing claim about the body's indispensability for thinking.
The lectures did report that Kant taught that "the constitution and also the state of the mind rests on the constitution and state of the body" (28:260-61). However, the examples discussed appear to belie this strong formulation:
[T]he constitution and also the state of the mind rests on the constitution and state of the body. E.g., one can enliven the mind by bodily motion, and vice versa (e.g., in society) enliven the body again by mental motions. We can thus get at the body through the mind, and at the mind through the body. (28:260-61)
Once again, the examples were vague and misleading, for they suggested not that the body's constitution had a decisive influence, but supported a fairly trivial and unimportant claim that mental agitation affects the body and vice versa. It is true that "anger can often make one sick" (28:260), but this in no way shows that the "state of the mind" rests on or is determined by the state of the body. There is no hint in the lectures that studying states of the body allows one to "get at" mental states in any specific or systematic sense.
This shows that one must be careful not to give the community thesis too strong an interpretation. Kant's claim that alterations of the soul are "at the same time" alterations of the body (28:259) could be seen as an echo of his radical views of the 1750s, but this interpretation ignores what is added by Kant's statement that the alterations of the body are at the same time alterations of the soul, which suggested that the soul's own powers are not to be understood as naturally overwhelmed by the body's influence. Kant did not specify the exact nature of the connection between body and soul, but he seems to have no longer accepted the view he defended in the Appendix to the Universal Natural History.
4.3.5 The embodiment thesis
Kant offered the embodiment thesis as an explanation for the community thesis. The reason that to every mental alteration there corresponds an alteration in the body is that the soul is embodied in a manner that makes the conduit thesis true for the soul/body community. Kant taught that "nothing can take place in the soul where the body is not come into play" (28:259). Although he obviously believed that our status as embodied knowers was important, it is unclear exactly what he taught his students. He claimed that the soul was distinct from the body, but that our knowledge of it derived exclusively from our experience of the soul/body community: "here we consider the soul in community with its body, and thus cannot know what the soul would be without this body, and the body without the soul" (28:261).
It is at this point that two significant questions were raised in the lecture:
The question is: from which side is most to be derived, from the body or from the soul? Further: would the soul, if it were to come into another body, have the same or another constitution and another state? We can say nothing about this, for here we consider the soul in community with its body, and thus cannot know what the soul would be without this body, and the body without this soul. (28:261)
These answers contradicted Kant's views of the 1750s. This is the best—and is decisive—evidence that Kant's understanding of the role of embodiment in cognition had changed significantly in the two decades after the publication of the Universal Natural History. Since, in the Appendix to the Universal Natural History, Kant maintained that the bodily action was essential to every aspect of cognition and that cognition would be impossible for a disembodied soul, he possessed strong reasons for concluding that the body contributed more than the soul. In the 1770s, however, he taught that "we can say nothing about this." Earlier he had an account of what the soul was like without the body (unchanging and without human cognition or any temporal succession of representational states) and he could draw some conclusions about what would happen if a soul became attached to a different body (it would be capable of better or worse cognition depending on the specific health and constitution of that body), but in this lecture he avoided drawing either conclusion.
The Metaphysik L1 lectures contained an implicit criticism of Kant's earlier views. Kant discussed two possible answers to his questions, materialism and Stahlianism. First he noted that to hold that "the most is to be derived" from the body really "amounts to" materialism, because it makes the soul explanatorily inactive:
Many maintain that all souls are the same, and the difference in the variety stems merely from the body. This amounts to materialism. (28:261)
In the Universal Natural History, Kant held this thesis, or at least a similar one, namely that souls do differ, but their differences do not matter because they are insignificant as compared to the influence of the body. In effect, this passage from the Metaphysik L1 criticized the dualism of the Universal Natural History as an explanatorily impotent epi-phenomenalism: a dualism that assigns the body too important a role in cognition "amounts to" materialism. It is clear that, by the 1770s, Kant had concluded that his earlier account of mind/body connection had exaggerated the body's importance.
The conduit thesis explained one reason why Kant may have believed this. When he delivered the Metaphysik L1 lectures, Kant believed that it was impossible to say whether it was the body or the soul the contributed the most to cognition because, in accordance with the conduit thesis, our experience is always of the body and soul as inextricably linked. This undermined Kant's ability to answer his question. Although in 1755 he had taken himself to have proved that the body was more important, in the mid-1770s he saw that he had no grounds for giving that answer.
In this regard, it is interesting to observe what the notes recorded was Kant's attitude towards Stahlianism, the view that the soul is supremely important for cognition. Kant taught:
If on the other hand we put all might in the soul, then we arrive at Stahlianism. Stahl was a physician who maintained this. One cannot wholly contradict this opinion, for all properties of the soul are already to be read in the countenance and lineaments of the body; thus the soul must have placed its properties in the body. Some have opined that it also even makes it body. (28:261)
By the mid-1770s, Kant still taught an account of embodied cognition, but his understanding of embodiment would have seemed utterly foreign to the author of the Universal Natural History. In that work, Kant was confident that he had refuted Stahlianism. In this lecture, however, he concluded that this cannot be done and that, furthermore, there is strong evidence that the connection between the body and soul is such that the active soul "places its properties in the body."
I have not yet addressed two central questions: Why had Kant's views about the mind/body connection, and the role of the body in cognition, shifted so dramatically by the mid 1770s? What, if anything, did this change have to do with the problems that crippled his early metaphysical system? The Rational Psychology section suggested that one answer to both questions was that Kant had developed a new understanding of the mind/body problem. He also had revised his earlier understanding of the nature of the soul and of its location.
4.4 A new understanding of the mind/body problem
In this section, I discuss one of the reasons that motivated Kant's conduit thesis and his new understanding of the mind/body relation. In the Rational Psychology section of the Metaphysik L1, Kant defended a new doctrine, that the soul is an object of inner sense only and is not an object of outer sense. In section 4.4.1, I discuss this "inner sense thesis" as well as a methodological shift in Kant's argumentation from metaphysical arguments about the nature of the soul to epistemic arguments about the possibility of our having inner sense.
In sections 4.4.2 through 4.4.5, I evaluate four conclusions that Kant used the inner sense thesis to ground. In section 4.4.2, I discuss why Kant believed that the inner sense thesis was able to resolve the contradiction in his rational psychology. I criticize Kant for not addressing the question of whether the fact that we experience souls through inner sense only is compatible with souls actually being objects of outer sense. A significant tension in Kant's discussion of the inner sense thesis was that he sometimes conflated epistemic claims about the nature of our experience of certain things with ontological claims about those things' natures. Although Kant had not yet developed a systematic critical methodology that avoided this problem, in section 4.4.3 I argue that Kant's awareness that the inner sense thesis did not entail the soul's immateriality showed that he was aware of the difficulty.
In sections 4.4.4 and 4.4.5, I discuss what Kant believed the inner sense thesis proved about the nature of the mind/body connection and about the soul's presence in space. I conclude in section 4.4.4 that Kant was correct to think that his distinction between objects of outer sense and objects of inner sense provided him with a new way to explicate the mind/body problem, but that it did not allow him to solve it. In section 4.4.5, I discuss how the inner sense thesis allowed Kant to use in a new way the distinction between local and virtual presence that he first discussed in the Inaugural Dissertation of 1770. Kant argued that the inner sense thesis entailed that the soul has a virtual presence in space and not a local presence, a status that he had accorded only to God in the Inaugural Dissertation.
This chapter ends with my conclusions about Kant's understanding of the mind/body problem in the mid-1770s. I conclude that although his understanding of mind/body connectedness was still inadequate, Kant's attempt to solve the problems of his earliest solution to the mind/body problem caused him to pose questions that would eventually lead him to several important critical views.
4.4.1 A key insight: the soul is an object of inner sense
The Rational Psychology consisted of an overview and three sections that discussed the soul from three different perspectives: considered "in and for itself," considered from the point of view of "comparison with other things in general," and considered with respect to its connection with other things. Among the topics included in the third section were the possibility, beginning, and end of the soul's connection with its body. These notes demonstrated that, by the mid-1770s, Kant's understanding of the soul in general and the mind/body problem in particular had shifted drastically. The key change was Kant's new doctrine that the soul is an object of inner sense only. This doctrine was articulated in the first section of the Rational Psychology, which contained arguments that the soul is a simple, unitary substance that is also "a spontaneous agent" (28:265). The discussion of the soul's substantiality included an important distinction between a narrower and broader conception of the self:
When I speak of the soul [in the first or transcendental part of rational psychology]…I speak of the I in the strict sense. We receive the concept of the soul only through the I, thus through the inner intuition of inner sense, in that I am conscious of all my thoughts, accordingly that I can speak of myself as a state of inner sense. This object of inner sense, this subject, consciousness in the strict sense, is the soul. I take the self in the strict sense insofar as I omit everything that belongs to my self in the broader sense. But the I in the broader sense expresses me as the whole human being with soul and body. But the body is an object of outer sense. I can perceive every single part of the body through outer sense, just like all other objects. But the soul is an object of inner sense. (28:265)
In the broader sense, I am a unified composite of body and soul, which are respectively objects of outer and inner sense. This distinction motivated a new approach to understanding the mind/body problem, and it provided Kant with what he took to be the resources necessary for resolving the problems that had caused him so much frustration when he wrote Dreams of a Spirit-Seer.
Kant's lectures on the doctrine that the soul is only an object of inner sense, which I call the inner sense thesis, were marked by an interesting transcendental shift. In earlier texts, Kant offered a priori arguments about the nature of the soul itself. In the Metaphysik L1, however, Kant drew inferences about the soul from premises about the nature of our cognition of it. As my discussion of Kant's use of the inner sense doctrine will prove, the focus of Kant's arguments shifted from the conditions necessary for existing in space to the conditions necessary for having outer and inner experience.
This shift led to a tension in Kant's lectures between epistemic and ontological interpretations of the inner sense thesis. Kant sometimes treated the claim that the soul is an object of inner sense as an epistemic claim: as an object of inner sense only, "the soul cannot be cognized from materiality," which is to say we cognize it through inner sense only and not through outer sense, the modality that gives us experience of material objects (28:273). This entailed that we cannot cognize or understand the soul as having an essential attractive force, an essential repulsive force, or the property of impenetrability, for these things are cognized through outer sense. Taken by itself, this epistemic claim might be understood as a version of the unthinkability thesis of Dreams of a Spirit-Seer: because we cannot cognize the soul through outer sense, whether or not my soul has a material nature or whether or not it is impenetrable are questions whose answers are "unthinkable" or uncognizable by me. However, Kant sometimes made a stronger claim about the inner sense thesis, namely that the epistemic limits it sets on our experience ground ontological claims about the nature of the soul. Kant taught that the inner sense thesis entails that souls do not have the properties that the objects of outer sense possess, such as having a local spatial presence and being impenetrable. For example, he taught that because the soul is an object of inner sense only, it follows that "the soul as well must not be an object of outer sense, but must rather be immaterial" and must therefore not possess "impenetrability in space" (28:272).
However, it is hard to understand why the epistemic claim that that the soul is not cognized as impenetrable would provide Kant with a proof of the ontological claim that the soul is not impenetrable. The general question is why should the claim that something is not cognized as X be taken as evidence that the thing is not X? Kant recognized this difficulty, for he commented that the ontological claim "we also cannot maintain so firmly and certainly, rather only so far as we are acquainted with it" (28:272). This qualification, however, was itself unclear and Kant never did fully resolve the tension between the stronger and the weaker interpretations of the inner sense thesis. By the mid-1770s, Kant's "transcendental shift" towards an investigation of the conditions necessary for having experience was still incomplete.
4.42 First application of the inner sense thesis: A solution to the impenetrability problem
Kant believed that the inner sense doctrine allowed him to resolve the contradiction that had plagued his rational psychology. I have shown that he faced this dilemma: to exist in our world, the soul must possess impenetrability, but to be an immaterial object it must not possess this property. Kant's solution was to argue, in effect, that it would be a category mistake to attribute the property of impenetrability to something that was only an object of inner sense. Since the soul is an object of inner sense only, Kant argued, there is no question of its being located in space through impenetrability:
The I shows that I have no concept of the soul other than of an object of inner sense. All objects of outer sense are material, and when they are present in space through impenetrability I thereby become aware of the objects of outer sense. But I am conscious of the soul through inner, and not through outer, sense; thus I comprehend that the soul is given to me as an object of inner sense. Further, we see that all actions of the soul, thinking, willing, etc. are no objects of outer sense; we can perceive through outer sense neither thinking nor willing not the faculty of pleasure and displeasure; and we cannot imagine how the soul as a thinking being should be an object of outer sense…Were the soul an object of outer sense, then it would have to be such by virtue of impenetrability in space; for only thereby do we become aware of objects through outer sense. But because we are acquainted with the actions of the soul from the side that is no object of outer sense, the soul as well must not be an object of outer sense. (28:271-72)
Although thinking and willing may be directed toward outer objects, the soul itself is an object of inner sense. If my soul were an object of outer sense, then I could become aware of it through outer sense; since I am aware of my soul through inner sense only, it follows that the soul is not an object of outer sense. Because objects of outer sense are such that we are aware of them "by virtue of impenetrability in space," Kant had an elegant solution to his dilemma about attributing impenetrability to the soul. It is true that, if the soul were an object of outer sense, then it would be an utter mystery how it could be present in space without being impenetrable. If, however, it was assumed that the soul is an object of inner sense, then Kant thought that this problem no longer arose, for, as something this is cognized only through outer sense, impenetrability is exclusively a property of the objects of outer sense. To be sure, this argument shed no light on how the soul is present in space on how it could act on objects of outer sense. However, it provided Kant with hope that he could escape the impossible situation he faced in the 1760s, namely that his own rational psychology inconsistently entailed that our souls are not part of our world. In section 4.4.5 below, I examine Kant's doctrine that objects of inner sense have a virtual but no local presence in the world.
Kant's earlier crippling sense of paradox was displaced and made palatable. In contrast to in Dreams of a Spirit-Seer, by the mid-1770s Kant was no longer mystified by how the soul could be present in our world but not possess impenetrability. The mystery that remained, that we "cannot imagine" how the soul could be an object of outer sense, was wholly benign since the inner sense doctrine provided the conceptual resources for rejecting the assumption that the soul was an object of outer sense.
This passage demonstrated the shift to transcendental questions that I referred to in section 4.4.1 above. Kant was no longer interested in such metaphysical questions as what are the conditions necessary for the soul to exist in space. Rather, on the basis of an analysis of our experience of our souls, we learn that the soul is an object of inner sense only. This conclusion, in turn, teaches us that certain metaphysical questions about the soul's local presence in space are illegitimate pseudo-questions. One might worry, however, that Kant made an illegitimate slide from transcendental to ontological claims. Did it follow from the fact that we have no outer experience of the soul that the soul is not present in our world "by virtue of impenetrability in space" (28:271)? Even if our experience is such that "I have no concept of the soul other than of an object of inner sense" would this entail that the soul itself is not the same type of object as the objects of outer sense (28:271)?
These questions are related to the second main problem with Kant's early metaphysics, that he could not prove that souls were not of the same material nature as physical monads. By the mid-1770s, Kant taught that all and only "objects of outer sense are material" (28:271). If he could demonstrate that souls were immaterial, then it would follow that he was entitled to conclude that souls were not the same type of things as objects of outer sense. If he could show this, then he could use his distinction between objects of outer and inner sense to develop a criterion for distinguishing material and immaterial simples. Thus if Kant could prove that—as an object of inner sense—the soul is immaterial, then the inner sense doctrine would have provided him a clear proof that the soul is not material: something would be material if it was an object of outer sense, and it would be immaterial if it was an object of inner sense.
4.43 Second application of the inner sense thesis: a proof of metaphysical dualism
Later in the Rational Psychology there was an argument that suggested that Kant believed that being an object of inner sense entailed immateriality. Kant first taught his students that they needed to separate the notions of simplicity and immateriality:
[I]mmateriality does not yet follow from simplicity, for the smallest part of a body is still actually something material and an object of outer sense. Although it is not immediately an object of outer sense, it can still become an actual object of outer sense through the putting together of many such small particles. Thus even if the soul were simple, it could still be material, and if it were put together out of other such simple parts, then it could become an actual object of outer sense. (28:272)
As I have demonstrated, Kant thought that matter was composed of material simples. Although we have no experience of those simples in isolation, when they are composed into matter they are objects of outer sense. If there are immaterial simples, they must be unlike this. As Kant put it, we would have no outer experience of an object composed of many immaterial simples:
…But what is no object of outer sense, that must not in the least degree be something bodily; and no matter how many such simple parts are put together, it still need not become a noticeable object of outer sense, for it is immaterial. (28:272)
If Kant could show that the soul is composed of one or more simples that possess this character (i.e., they do not become objects of outer sense when combined together), then he could conclude that the soul is immaterial. But how could he show this? As Kant asked his students, "From what can a philosopher prove the immateriality of the soul, and how far can he go" (28:272)?
Although the textual evidence is ambiguous, Kant seemed to have ultimately recognized that the inner sense thesis was not sufficient to prove the immateriality of the soul. The sticking point was his belief that the soul is simple. If souls were complex, then we could infer from the fact that we have no outer experience of souls that they are not composed of material simples, for Kant believed that we do have outer experience of composites of material simples. However, Kant maintained that souls are simple. Since we have no outer experience of material simples, it appears that the inner sense thesis does not exclude the possibility that a soul is a material simple. This is why the inner sense thesis did not entail that souls are of an immaterial nature, in contrast to physical monads.
What the inner sense thesis claimed was that souls are unlike material objects, which are objects of outer sense. However, the explanation of this might simply be that material objects are composites whereas souls are simple. What Kant required was a way to evaluate the question I discussed above: Is the soul the sort of simple substance that is cognizable through outer sense when it is combined with other simples?
In the Metaphysik L1 lectures, Kant returned to the thought experiment of the opening pages of Dreams of a Spirit-Seer. Here he argued against what he identified as the Wolffian view that simplicity implied immateriality, but he offered no proof of his own of the immateriality of the soul:
If we imagine a cubic inch filled with matter, and one asked: if the soul is merely simple,, would it take up space there so that precisely such a simple part would have to be taken away, in whose position it would enter? Or would it have a place therein, without that happening? If the first is maintained, then it would have to follow that if I continue this with the second, third, fourth, and following souls, I ultimately remove all matter form the cubic inch and have the whole cubic inch full of souls, which would be present in space through impenetrability. (28:272)
If the soul could enter that cubic inch without displacing any of the material simples that filled it, then the soul could not be a material simple.
I believe that Kant saw that the inner sense thesis could not be used to prove that the immateriality of the soul, because to argue that a soul would not displace a material simple on the grounds that souls are objects of inner sense would simply beg the question. An argument connecting the inner sense thesis to immateriality would work only if one could justify the claim about souls that "no matter how many such simple parts are put together, it still need not become a noticeable object of outer sense" (28:272).
Kant gave no independent defense of this claim. Sometimes he seems to have merely assumed that this was entailed by the inner sense thesis, although in other passages he admitted that he could not prove this. After noting that "we cannot prove a priori the immateriality of the soul, but rather only so much: that all properties and actions of the soul cannot be cognized from materiality" (28:273), Kant commented that "these properties do not yet prove that our soul should have nothing outer" (28:273). This implies that he recognized that the inner sense thesis did not entail that an object of inner sense cannot also be an object of outer sense, and thus that the inner sense thesis did not entail that souls are immaterial.
I conclude that Kant was aware that ontological claims like those did not follow directly from epistemic claims such as that the soul cannot be cognized from materiality. Although this is a serious tension in the lectures, Kant did seem aware that that epistemic claim was compatible with the possibility of souls' materiality.
Kant did provide one brief argument for souls' immateriality. Since space is infinitely divisible, "there is no simple part of matter, but rather each matter is in space, and thus is divisible to infinity" (28:273). He concluded that "no part of matter is simple, for that is a contradiction; thus the soul is also not material, but rather immaterial" (28:273). Unfortunately, Kant said no more than this. This argument would be valid only if Kant had already proven that there are no physical monads, namely simple material substances that were simple constituents but not extended parts of matter. Since physical monads were not identical with the extended parts matter, Kant's argument proved only that souls are not matter, not that they do not share the same nature as physical monads.
Thus even in this late pre-critical text, Kant lacked the resources needed for proving that souls did not possess the same material nature as the simple constituents of matter. He required a more sophisticated account of inner sense that explained the exact connection between being an object of inner sense and not being material. By the time he had presented a more elaborate theory of inner sense in the Transcendental Aesthetic section of the Critique of Pure Reason and other critical texts, it was too late to resurrect Kant's rational psychology. By this time, Kant had jettisoned an assumption that he never questioned in the pre-critical period, the assumption that the soul is a substance.
4.4.4 Third application of the inner sense thesis: A new understanding of the mind/body problem
There was no hint of these developments in the Metaphysik L1 lecture. Instead, Kant constructed a new account of mind/body connectedness on the unstable foundation of his early inner sense thesis. He took himself to have a new conception of the mind/body problem, a conception that differed markedly from the one he had defended in Living Forces. The lecture notes reported Kant as having argued:
[T]he interaction between soul and body is a reciprocal dependence of determination. Accordingly, we ask first: how is such an interaction possible between a thinking being and a body?…The ground of the difficulty in comprehending this interaction rests on this: the soul is an object of inner sense, and the body is an object of outer sense. I am aware of nothing internal with the body, and nothing external with the soul. Now it cannot be conceived through reason how that which is an object of inner sense is supposed to be a ground of that which is an object of outer sense. Thinking and willing are mere objects of inner sense. Were thinking and willing a motive power, then they would be an object of outer sense itself. (28:279).
The problem, as Kant understood it, was that "it cannot be conceived through reason" how objects of inner sense can ground determinations of objects of outer sense and vice versa. In Living Forces, Kant maintained that the apparent heterogeneity problem was not serious, for material and immaterial substances all act in the world through the successive exertion of vis activa. In the mid-1770s, however, Kant endorsed exactly the opposite position: there is a genuine heterogeneity problem, he argued, for only objects of outer sense can be the cause of motion.
The lecture notes made clear that Kant believed that the inner sense thesis posed a serious problem for understanding how souls can act on bodies and how bodies can act on souls. Kant taught:
[B]ecause thinking and willing are merely objects of inner sense (thus a ground of inner determination), then this is difficult to comprehend, how these can be a ground of outer determination. And since, on the other hand motion, as an object of outer sense, is a ground of outer determination, it is hard to determine how this can then be a ground of inner determinations and representations. (28:279)
The relevant difference between bodies and souls is this: bodies, as objects of outer sense, act by changing outer determinations whereas souls, as objects of inner sense only, act only by changing inner determinations. Kant concluded that there were no prospects for a theoretical solution that would explain how bodies can cause representations or how mental actions can cause changes in bodies' motions.
In 1766, Kant had found this admission difficult to embrace. In contrast to in Dreams of a Spirit-Seer, in the Metaphysik L1 Kant accepted this position with equanimity:
We cannot have insight through reason into the reciprocal determination between thinking and willing and between moving. The impossibility of comprehending this through reason, however, does not at all prove the inner impossibility of the matter itself. But through experience we can comprehend it; and indeed this applies not here alone, but rather all basic powers are given to us through experience, and none can be comprehended through reason. (28:279)
Kant's claim that our experience of mind/body interaction allows us to "comprehend" this interaction is hard to take seriously, for in the next sentence he concluded with no reservation that this interaction "cannot at all be comprehended" (28:280). Whatever insight our experience of mind/body interaction affords, Kant concluded, it does not contribute to a philosophical explanation. Thus he taught that "all systems of explaining the soul's interaction are fruitless and in vain." Indeed, Kant's considered opinion seems to have been that the "comprehension" given by experience was extremely limited, for it presupposed that "we already assume powers of interaction" (28:280).
In contrast to in Dreams of a Spirit-Seer, Kant did not see this limited comprehension as merely empty. He was now willing to call it "comprehension" even though it did not provide thoroughgoing or comprehensive insight. Kant no longer viewed the inability of reason to explain basic powers as a scandal for philosophy, but he did view this as a factor that fundamentally limited what philosophy could achieve. The inner sense thesis may have helped Kant to see that our inability to experience our souls in outer sense did not entail that mental action is "unthinkable." However, although Kant may have possessed a new way to explicate the mind/body problem, his distinction between objects of outer sense and objects of inner sense did not allow him to solve it.
4.4.5 Fourth application of the inner sense thesis: the presence of the soul in space
In the mid-1770s, Kant taught that the inner sense thesis entails that the question "where is the soul located in space" was—like the question, "does the soul possess impenetrability"—a fundamentally illegitimate question. He argued:
[I]f the soul is no object of the outer senses, then the conditions of outer intuitions also do not belong to it. The condition of outer intuition, however, is space. Now since it is no object of outer intuition, it is also not in space but rather works only in space; -- and although we say by analogy, it is in space, we must still not take this in a bodily way. Likewise, one says that God is in a church…[T]he soul has no particular location in the body; but its location in the world is determined by the body, and it is immediately connected with the body. (28:292)
Kant here repeated what he argued in Section 27 of the Inaugural Dissertation (1770): like God, the soul has a virtual, not a local, presence in space. The thesis of that section was "the supreptic axiom of the first class is: Whatever is, is somewhere and somewhen" (2:413-14). This assumption was doubly spurious. First, as I have demonstrated it followed from Kant's notion of a world that some things may exist but may bear neither spatial nor temporal relations to objects in our world (e.g., something may exist but exist in no world at all, or it may exist in a different world). Second, of the objects in our world it amounts to a category mistake to assume that objects of inner sense are locally present in the world. In particular, it is a mistake to assume this about souls. The virtual presence of our souls in space is determined by the local presence of our bodies, because this is where our souls affect the spatial world. This does not imply, however, that our souls either penetrate or are located in some empty space of our bodies, just as that souls can have a virtual presence in our world does not imply that they possess impenetrability.
Kant's lectures about the virtual presence of the soul in Metaphysik L1 contained an interesting discussion of the role of the body in cognition. We are justified in viewing the brain as the "seat of sensation," Kant argued, because the nerves in the brain are conditions of the soul's having sensations:
[T]he soul must put the seat of its sensations in the brain, as the location of all conditions of the sensations. But that is not the location of the soul itself, but rather the location from which all nerves, consequently all sensations as well, arise. (28:281)
This passage is additional evidence that, by the mid-1770s, Kant saw the main role of the body in cognition as delivering sensation to the mind. Kant's new agnosticism about whether the soul or the body contributes more to cognition explains why he focused on sensation. It is likely that, if he had still believed that the body was indispensable for all cognition, he would not have limited this discussion to sensation alone.
4.4.6 The mind/body problem in the mid-1770s
In the mid-1770s, Kant had neither solved nor dissolved the mind/body problem, but he also was no longer paralyzed by the problems that undermined his earliest solution. By 1766, he no longer accepted the solution he defended in Living Forces, but he did not know how to go forward. What had changed by the mid-1770s? In the Metaphysik L1 lectures, he reaffirmed the skepticism about understanding primary forces that had so worried him in Dreams of a Spirit-Seer. He also affirmed the impossibility of a philosophical explanation of mind/body interaction and, since he had not yet rejected his fundamental pre-critical assumption that the soul is a substance, he could not dismiss the mind/body problem as a pseudo-problem as he did later in the Parologisms section of the Critique of Pure Reason.
However, I have demonstrated that Kant's attitude towards primary power skepticism had softened, not the least because he believed it provided a powerful antidote to dogmatic a priori speculation. The most Kant could say was that experience shows us that interaction occurs and that philosophy cannot demonstrate that this interaction is impossible. Even given these strictures, Kant might well have considered his position an improvement over the dogmatism of Living Forces and the crippling skepticism of Dreams of a Spirit-Seer. Although he was far from the mature critical position on the limits on solving metaphysical problems, Kant's specific struggle with problems in the philosophy of mind quickened his pace on a path that led to that view.
A chief advantage of Kant's position in the mid-1770s was that it offered a solution to the heterogeneity problem. In Living Forces, Kant had argued that material and immaterial substances were fundamentally homogenous because all substances act by exerting vis activa successively, but I have shown that this effectively caused Kant's distinction between materiality and immateriality to collapse. By the time he gave the Metaphysik L1 lectures, Kant used the inner sense doctrine to defend the heterogeneity of body and soul: bodies are objects of outer sense, souls objects of inner sense.
Kant's new understanding of the soul's virtual presence in the world was a clear advance over his former doctrine, which entailed that the soul could act in this world only if it was impenetrable, that is only if it had a local presence in space. Although Kant had not yet adopted the critical view that the soul is not a substance, his doctrine of virtual location avoided the contradictions and difficulties of his earlier view. Likewise, Kant's moderated concern with embodiment was an improvement over his strong claims in the Universal Natural History, for his defense of the community thesis in the Metaphysik L1 recognized that our embodiment is important for cognition while providing more room for an account of the soul's spontaneity. Although he gave no precise reckoning of the role of the body in cognition, Kant's abiding interest in our embodiment shows that this is a much-overlooked train of Kant's thought.
I shall close with a reminder that, whatever its advances, Kant's position in the mid-1770s was not critical and, indeed, was fundamentally unstable. I have shown that the inner sense argument was not enough to provide Kant with a decisive proof of souls' immateriality. Kant's response to his failed metaphysical system of the 1740s and 1750s was thus only partially successful. Nonetheless, I have proven that, by the mid-1770s, Kant's struggle to understand the mind/body connection caused him to raise questions related to two crucial critical views. First, he developed the doctrine of inner sense, which he had first articulated in the Inaugural Dissertation of 1770. He provided a new application of this doctrine that caused him to raise questions that led to the critical view of the self. Second, his attempts to ease the problems that had so anguished him in the mid-1760s eventually culminated in the development of systematic critical strictures on metaphysical reasoning. These and other problems would prompt another important step, the rejection of the assumption that the soul is a substance, but that is another story.
NOTES
143. I owe this characterization of Kant's thesis—and this name—to Daniel Warren.
144. All quotations from the Lectures on Metaphysics are from Immanuel Kant: Lectures on Metaphysics, tr. and ed. by Karl Ameriks and Steve Naragon (Cambridge: Cambridge University Press, 1997).
146. More precisely, in 1766 Kant endorsed the conditional claim that if one presupposes that the soul is an immaterial substance, then it follows that the soul must be present through its body. He believed that our own experience of sensation gave grounds for asserting this conditional, but in 1766 he also believed that we had no grounds for asserting the conditional's antecedent. The paragraph where Kant discussed this in Dreams of a Spirit-Seer—2:312—strongly suggests that Kant accepted this conditional in earlier pre-critical works, that he endorsed its antecedent, and thus that he was committed to its consequent. See section 3.4.1 above. I am grateful to Daniel Warren for fruitful discussion of this passage.
147. He first employed this notion in the Inaugural Dissertation of 1770, although there he applied it to God's presence and not to the presence of souls and other immaterial substances. See especially Inaugural Dissertation sections 19 and 27.
148. For the history of the notion of the soul's virtual location, see Robert Butts, Kant and the Double Government Methodology (Dordrecht, Holland: D. Reidel, 1984), pp. 103-116. In section 27 of the Inaugural Dissertation, Kant praised Euler's doctrine that God has a virtual but not a local presence in the world.
150. See sections 3.2.3 and 3.2.4 above.
153. Kant also argued this in the Inaugural Dissertation, although there he was not as firmly committed to monotheism as he was reported to be in Metaphysik L1. In sections Inaugural Dissertation sections 21 and 22, he held that a plurality of worlds would require a plurality of Gods. I am grateful to Daniel Warren for pointing this out to me.
154. The introduction to Chapter Four contains a preliminary sketch of these theses.
155. On this see Ameriks' helpful "Concordance of Kant's Lectures on Metaphysics," in Immanuel Kant: Lectures on Metaphysics, pp. 524-551.
160. I discuss the unthinkability thesis in section 3.3 above.
161. See sections 3.3.4 and 3.4.3 above.
163. See sections 3.2.4 and 3.3.4 above.
164. According to the lectures, Kant concluded:
We are thus acquainted only with those powers in the body whose effects are phenomena of outer sense; and in the soul we are acquainted with no other powers than those whose effects are phenomena of inner sense. Now how the powers of outer sense can be grounds of the phenomena of the soul, and the powers of the soul can be grounds of the phenomena of he body, cannot at all be comprehended. (28:279-80).
165. In the Note to the Inaugural Dissertation, Kant gave a helpful explanation of this view. He concluded:
[T]he soul is not in interaction with the body because it is detained in a certain place in the body; a determinate place in the universe is rather attributed to the soul because it is in reciprocal interaction with a certain body; and when this interaction is interrupted any position it has in space is destroyed. And, thus, its locality is derivative and is bestowed on it contingently; it is not a fundamental and necessary condition attaching to its existence. (2:419; Kant's emphasis)
167. There has been much attention recently to Kant's alleged "bodily asceticism." For example, both Robin May Schott and Andrew Cutrofello maintain that Kant's bizarre medical habits stem from a sterile asceticism and a profound alienation from his own body, an alienation which led to his ignoring the philosophical significance of embodiment. See Schott, Cognition and Eros: A Critique of the Kantian Paradigm (Boston: Beacon Press, 1988) and Cutrofello, Discipline and Critique: Kant, Poststructuraism, and the Problem of Resistance (Albany: State University of New York Press, 1994). Among the defenders of my position—that Kant was keenly concerned with embodiment—are Susan Shell, Karl Ameriks, and Lorne Falkenstein. See the third chapter of Falkenstein's Kant's Intuitionism (Toronto: University of Toronto Press, 1995), the first section of Shell's The Embodiment of Reason (Chicago: Chicago University Press, 1996) and Ameriks' Kant's Theory of Mind (Oxford: Oxford University Press, 1982), pp. 99-108.