Alyona Kharitonova. The concept of body and the problem of demarcation in new European metaphysics: from Descartes to Kant

1.      Matter: Between Physics and Metaphysics

The development of philosophy during the early modern period was strongly orientated towards scientific methodology. That caused the transformation of its subject and self-grounding strategies. Since antiquity mathematics was considered to be the classic model of scientific knowledge. The early modern period presented the significant progress in natural science, which used to be developed within the frame of metaphysic and then aimed to become a separate discipline. That progress was made mainly due to the adoption of mathematical methods and metaphysics was forced to redefine its scientific status. The discussion provoked by the theme offered by the Berlin Academy of Sciences for essay contest in 1763 can be mentioned as an example. Its short wording was the following: are metaphysical sciences capable to provide the same degree of certainty as mathematical sciences do? Most of the contestants’ essays gave negative answers (among the authors who entered the competition were M. Mendelssohn, I. Kant, J.H. Lambert). However, they pointed out that metaphysics was a science of a different kind in comparison with mathematics, so metaphysical truths had the other kind of certainty. The present article sets a goal to examine the demarcation of philosophy and natural sciences in the field of body notion discussion. That discussion has a long history that interchanges with natural science and presents the contest of different metaphysical and physical conceptions.

1.1 New Interpretation of Matter: Mathematization of Nature

The process of the so-called mathematization of nature was the foundation for modern science. Material nature was the main subject of physics[1] and the breakthrough made by natural science in the 17th century was provided by revised interpretation of matter notion, which gained a brand new understanding different from one given by antique authors[2]. Revolution was made by G. Galilei who aimed to eliminate “impassable gap between mathematical construction and physical object” [3, p. 102], in other words to ground mathematical physics. He reconsidered features that used to be applied to matter in antique tradition (such as mutability and instability) and reckoned invariability and self-identity among its main qualities.

1.2 Descartes: Extended and Passive Matter

The decisive step towards overcoming the difficulties that Galilei faced establishing the identity of mathematical and physical knowledge[3] was taken by R. Descartes. Matter in his theory is identical to space. Descartes was the first to postulate the existence of two substances[4] which were not just different but mutually exclusive. He claims: “Similarly, from the mere fact that each of us understands himself to be a thinking thing and is capable, in thought, of excluding from himself every other substance, whether thinking or extended, it is certain that each of us, regarded in this way, is really distinct from every other thinking substance and from every corporeal substance” [8, p.180]. Descartes’ rigorous dualism is remarkable for making it possible to grasp nature as a mechanism which supposes the possibility of its complete rational cognition. That has two crucial consequences. For metaphysics that means a reduction of such notions as “mind”, “soul” or “spirit” (which differ in the antique and medieval philosophy) to the notion of “thinking thing”. For physics that means not only identification of matter and space, but also rejection of vacuum. This thesis leads to assumption that an action can be transferred only by a direct interaction of two bodies and raises a thorny issue of explanation how mind and body interact.

1.3 Newton: Inertial Matter

Identification of matter and extension was strongly criticized, especially by I. Newton and G.W. Leibniz. Newton’s famous statement “hypotheses non fingo” appeared as criticism of Cartesian physics. Experience and experiments must precede hypotheses, general and obvious statements in contrast to what Descartes had claimed. Newton’s physics is important for us in two aspects. Firstly, it contains the idea of force as a non-mechanic cause. Secondly, it implies an idea that the first cause concerns rather metaphysics than physics[5]. Introducing such notions as force, universal gravitation, absolute and relative space and time Newton makes Cartesian notion of matter, which included both space and bodies, incongruous. However, there exists a certain resemblance between physics of Newton and Descartes. Both consider matter as lifeless (Descartes) or less radical as inert (Newton) which demands impact of external forces, whose nature is not completely defined and can be bound with divine intervention[6].

1.4 Leibniz: Animated Matter

The position of Leibniz concerning the correlation of spiritual and corporeal is not unambiguous one. Unlike Descartes and Newton his matter notion includes an idea of activeness. He claims two kinds of substances exist: simple ones with no parts (monads) and composite ones that consist of those simple (bodies). Monads differ according to the degree of perception: they can be either distinct or confused (common physical bodies)[7]. According to Leibniz, nothing in nature is incapable of perception, so Cartesian interpretation of matter is unacceptable. Leibniz distinguishes between two types of matter: primary matter (“mass”) is passive, impenetrable and extended and is not a complete substance, whereas secondary matter is substantial and includes active force. Exactly this matter is the subject of examination in physics. Thus real bodies that surround us can be seen as mass (they are partible and impenetrable) but at the same time they contain active force. In Cartesian system soul as thinking and perceptive substance is placed outside and isolated from corporeal world, while Leibniz places it in the grounding of the whole nature. However, the difficulty concerning the fact how immaterial monads form the base of any body remained unsettled.

2.      Cartesian Anthropology: Dualism of Human Nature

The key demand that metaphysics made on itself during the new modern period was for conforming to criteria of science. Descartes made headway in finding the common ground for metaphysics and natural science. However, his interpretation of human nature constituted the crucial problem for metaphysics. The main peculiarity of Cartesian dualism is the claim that there are two essentially different and independent substances: mind and body. The whole idea of human being is based on this assumption and apparently a man is the only example of two substances bound[8]. According to Cartesian model, various phenomena and processes in human being proceed solely and independently and can be clearly referred to one or the other substance. There is a certain parallelism between these processes but they are not connected[9]. There occurs an important shift in grasping human nature which is nothing else but the nature of mind as a man is considered first of all as “thinking thing”. Descartes writes: “…as regards reason or sense, since it is the only thing that makes us men and distinguishes us from the beasts, I am inclined to believe that it exists whole and complete in each of us” [6, p. 21]. That testifies to evidently stated substance hierarchy where thinking substance has implicit superiority over corporeal one. Although human being presents a certain unity of mind and body, only the feature distinguishing him from other creatures is essential.

Descartes faces an essential problem: how the interaction between two substances is enabled if they are entirely self-sufficient. Therefore a special organ (pineal gland) which provides coherent actions of mind and body is introduced. This gland in particular enables perception, the process that demonstrates coherent parallel action of two different substances[10]. Many philosophers later criticized Descartes’ position in that question emphasizing that soul was joined to the whole body and not placed just within one part of the brain[11], although he expressed the same idea as well: “… we need to recognize that the soul is really joined to the whole body, and that we cannot properly say that it exists in any one part of the body to the exclusion of the others” [9, p. 229]. Nevertheless, his reference to the gland does not seem to be a convincing solution. Firstly, the data available in contemporary physiology and anatomy testified the existence of that gland with animals and that clearly contradicted Descartes’ idea to consider animals as merely mechanisms not capable of thinking. Secondly, Descartes’ views on the place and functioning of the pineal gland did not correspond with scientific facts known at that time. Last but not least, such concept is rather doubtful as it interferes with the primary principles of dualism. So, the consistent theory concerning the interaction between mind and body is hardly presented in Descartes’ writings. Although the number of interpretations in research literature is overwhelming, each of them fits one passage or another but barely one grasps all his statements on the problem.

3.      Body as a Problem: View of Wolff

After Descartes the problem of representing human being becomes the crucial point for metaphysics. On the one hand, human being is a “thinking thing” and cognizes the world. On the other hand, human being is embodied which means the settlement of thinking in the material world and makes it rather difficult to give a homogenous representation of a man. Metaphysics has to deal with a particular type of bodies correlated with thinking which disrupts the homogeneity of material bodies studied in physics.

3.1 Dualism Problem: Exposition and Various Solutions

A lot of thinkers attempted to overcome inconsistency in Cartesian theory. Main solutions are presented on the base of the so-called “German Metaphysics” by Chr. Wolff (“Rational Thoughts on God, the World and the Soul of Man, and on All Things Whatsoever”) that was first published in 1720 and reissued many times with amendments and additions by the author[12]. It contains a chapter which describes soul essence and different types of spirits in general. Wolff claims it is essential to understand how thought correlates with body motions, so the considerable part of that chapter scrutinizes main conceptions clearing the question that had been shaped by that time.

The first hypothesis called Physical Influx states that “unity (Gemeinschaft) of body (Leib) and soul is based on the natural influence of one thing on the other” (§761). Wolff gives the following comment: “And this opinion of common people was shared for some time even by philosophers, although nowadays only few agree with it” (§761). Although this hypothesis agrees with common sense and everyday experience most of all, one can not say there are any evidences in favour of it in experience because we do not have any clear notion of soul activity which causes body motions (Leib)[13].

Then Wolff presents Descartes’ point of view. According to it, the only basis of mind-body unity is the will of God: “… it is rather God causes thoughts in soul with motions in body (Körper) and on the other hand – motions in body (Leib) with soul and its desires” (§763). Although that point of view still has a lot of supporters, there are quite a few counter evidences. It should be mentioned that Wolff presents this theory not accurately enough as the explanation of mind-body interaction exceptionally by the God’s will belongs not to Descartes himself but first of all to N. Malebranche[14]. Although it is not a simple task to reconstruct the point of view of Descartes himself, the assumption that he proposes the solution just in terms of Occasionalism seems to be rather awkward.

Pre-established Harmony is the last of the hypotheses and Wolff tends to support it. According to it, only the interaction between substances of one type is possible, while semblance of interaction between different substances is provided by pre-established harmony existing in the world. All possible changes are inherent in each monad and the harmony means God has created substances so that each of them completely reflects others in its internal changes like in a mirror. It is inappropriate to talk about interaction as we deal with some simultaneous and pre-established changes. Despite some common ideas with Occasionalism, this hypothesis has more advantages, especially in its implementation in physics: divine intervention has occurred just once by world creation and there is no need to appeal to it on each interaction. Thus, matter is endowed with particular independence and the problem concerning the status of beasts, which, according to Descartes and Malebranche, have neither soul nor consciousness, is solved as well.

3.2 Dualism Problem: Further Prospects

Although Wolff presents Pre-established Harmony created by Leibniz, some aspects have been modified[15]. At the same time all three theories are exaggeratedly presented just as hypotheses. Research literature contains different appraisals of that fact. According to R. Blackwell, such presentation temporarily brought down the sharpness of the question. However, J. Zamitto claims that the publication of “German Metaphysics” led to a new wave of discussions and initiated argumentation for Physical Influx and against Pre-established Harmony. After intense debates Physical Influx took a revenge on other theories in quite a short time[16].

Each of the described theories presents its own way of bringing metaphysics to the scientific basis. Physical Influx solves that problem by peculiar equating mind and all types of bodies as they all have something common in their structure, namely forces [32, p. 196]. For Occasionalism the problem is solved besides our knowledge and does not demand any special explanation. As for Leibniz, the spiritualistic interpretation of all existing things gains priority along with the thesis that each body is animated and no soul can exist on its own.

4.      Körper vs Leib: Notion Correlation

The hypotheses examined by Wolff aim to give a scientific explanation for all possible substance interactions, which can be either physical (between bodies), or psychological (between spirits), or psychophysical. The latter becomes a stumbling block to all theories as it involves body which demands the scientific rather than mystic or irrational explanation.

German writings that belong to the considered period, unlike Latin ones, contain two different notions to denote body. When it comes to any material body that is considered in physics or geometry, it is called “Körper”. The notion “Leib” is used to mark those bodies that are bound with soul, namely human bodies. In Latin texts the notion “corpus” is mainly used in both cases. However, that distinction in the usage is not always maintained[17]. The following reconstruction of the Wolffian system aims to establish the correlation of these two notions.

Wolff claims that the world is the range of changing things, therefore it is a composite thing itself. Besides, “the world is also a machine” [34, S. 337, §557]. Any physical body exposed outside ourselves is a composed thing – “Körper” – can be called machine as well. “Among these bodies there is one we recognize as our own body (Leib) because according to it our thoughts concerning other bodies are directed and because it always exists along with us while all other bodies change”, says §218. Despite these peculiarities, the main of which is the compliance (Übereinstimmung) of some bodies with soul, this kind of body can be grasped with the “machine” notion as well because “Leib” is “just a machine devoid of reason” [34, S. 487, §781][18]. The notion of machine itself can help to clear up why it is essential for Wolff to equalize the usage of two body terms by giving them a common equivalent: “From mentioned above it is possible to conclude […] that bodies are purely (lauter) machines and that is why there is truth in them (§142) and they can be clearly explained (§77)”. As the whole world is a machine, “… all events in it happen to be reliable” (§561). The equivalence between body notions and machine notion eliminates the lack of regularity in the concept of human body. Defining truth in contrast to dream Wolff follows Leibniz and points out consistency and sequence of changes happening to a thing as the criteria[19]. Postulated sequence functioning of human body aims to disguise the absence of reliable idea how mind and body interact. Being bound with soul but still remaining “purely a machine” human body sets the general problem: how can we inscribe activity of mind into universal physical laws? Human body should be similar to any other body in the world and it can not just provide dreams, affects or passions, thus the presentation of human being is constituted so that it will not contradict the rational sway, the distinctive feature of human being.

Although the formal distinction between two notions is rather clear, it would not be correct to talk about strict and systematic usage of these terms in writings of the 18th century due to their equivalence to “machine” notion. Moreover, the term “Körper” prevails[20] not accidentally: whatever differences can be found in theories explaining mind-body interaction, all of them are still orientated towards Cartesian interpretation of any body as a mechanism, more or less complicated configuration of passive matter.

5.      Kant’s pre-Critical Writings

For Kant the problem of grounding the scientific character of metaphysics was rather vivid throughout all periods of his work (however its interpretation was not necessarily the same as we have nowadays). Previous thinkers who tried to solve the above mentioned task inevitably faced the mind-body problem, which in Kant’s writings is never the main theme. The connection between these two problems does not exist any longer and the mind-body problem turns out to be eliminated. Nevertheless, it could not be totally ignored and arose in different writings in pre-Critical, Critical and even quite late writings (for example, “Anthropology” or “Pedagogics”). In his Critical writings Kant deals with the question “How is metaphysics possible as science?” in a rather different way and claims that objects must conform to our cognition and not vice versa as it was before. As for his pre-Critical writings, they were merely influenced by previous discussions so some of them contain passages presenting Kant’s attitude to the mind-body problem.

5.1 Rationalism and Common Sense

Kant expresses his opinion on the mind-body problem rather carefully. The writing “Dreams of a Spirit-Seer Elucidated by Dreams of Metaphysics” (1766) is of special interest as it contains likely the largest amount of reasonings concerning human body, soul, other spirits and relations between them. This writing is aimed at critique of E. Swedenborg, Kant’s well-known contemporary. The second part contains critique and even mockery of his position, though the content of the first one is not so unambiguous. It can be interpreted as a specially constructed model which demonstrates theoretical groundings of Swedenborg’s position which is opposed in the second part, but another interpretation is possible as well. According to it, reasoning in the first part presents those few things which can be said definitely about nature of soul and body. So they can be seen as proper Kant’s position and this interpretation in particular will be the base for further analysis of that writing.

The question “where is the place of this human soul in the world of bodies?” [16, p. 312] arises as merely hypothetical and can become valid only when we prove that soul is a spirit. Kant strongly criticizes Cartesian point of view as it may only be based on “imaginary interferences”. At the same time he mentions a quotation from J.G. Daries: “My soul is wholly in my whole body, and wholly in each of its parts” [16, p. 313]. So, according to Kant, when it comes to vague questions which nevertheless have to be somehow solved it is necessary to rely on ordinary experience and common sense rather than on sophisticated reasoning. That is likely connected to the idea that soul and spirits can not be cognized in experience[21]. Even if we venture to decide where soul is situated, the most plausible answer will be the following: “where I feel, it is there that I am” [16, P. 312] as soul permeates the whole body that is allocated to it. The allocation of a particular body means that it must alter along with me and have the same place as I have – the similar idea was presented earlier by Wolff. It is worth mentioning that Kant, like Wolff, does not clear how in particular a body becomes my body. There is no description of any specific features of a body that can be connected with soul and therefore can be called ‘Leib’.

5.2 Changes in Substance Notion

Besides Kant’s attitude to the mind-body problem was formed with consideration of Hume’s sceptical philosophy, so different substance questions (definition, classification etc.) appear to be in the background. It does not mean that Kant avoids this term: it appears rather often in his pre-Critical writings when he presents his own version of Physical Influx; in “Critique of Pure Reason” it also plays an important role in parts concerning the table of categories and analogies of experience. However, it can not be said that the usage of this notion was fully adopted from the preceding tradition. Kant’s position on the substance notion underwent some essential changes already in the pre-Critical period but the general tendency led towards the loss of significance of the term[22]. In Critical writings the substance notion finally loses its fundamental ontological status as it concerns phenomena and not noumena[23].

Thus the crucial boundary between soul and body is not an obvious thesis for Kant. Although nearly all human actions can be referred to either cognition or material processes, our everyday experience can hardly be presented as a sequence of mental and material phenomena. Besides, Kant refuses to consider the substance question as a prior one. These changes weaken traditional dualistic hierarchy that was presupposed in all theories explaining the mind-body problem.

5.3 Soul and Body: Demolition of Hierarchy

The transformations enabled by Kant lead to overcoming the statement that the relation between soul and body is asymmetrical, which causes a change in presenting the outer and the inner of human being. A traditional model of a man considers soul activity to be inner and matter activity to be outer, whereas joint activity of soul and body emphasized by Kant displaces that bound as well.

“Thoughts on the True Estimation of Living Forces” contain the following argumentation: “… the soul must be able to act externally by reason of the fact that it is in a location”. At the same time, “… matter that has been set in motion acts on everything that is spatially connected with it, and hence also on the soul”, “… it changes the internal state of the soul insofar as this state is related to what is external to it”[24]. Moreover, the inner state of soul can be also counted to the outer as “… the entire internal state of the soul is nothing other than the summation of all its representations and concepts” [20, p. 25]. Thus, as the whole content of soul activity refers to the outer, soul can not be seen as a “bastion” of inner. Kant rejects that soul can be found in one particular part of human body, on the contrary, the whole body can be presented as the location of soul because it is situated in each part of it equally. Furthermore, body activity influences and rather determinates the condition of soul. Another proof of that thesis can be found in the third part of “Universal Natural History and Theory of the Heavens” (1755): “… it is nonetheless certain that the human being, who derives all his concepts and ideas from the impressions the universe stimulates in his soul through his body, depends totally on the constitution of this matter to which the creator has bound him for both their clarity as well as the skill to connect and compare them, which we call the faculty to think” [20, p. 298]. In a range of pre-Critical writings (including lectures on anthropology) Kant mentions that people’s capacity to think differs a lot, so it can be concluded the capacity simpliciter depends on physical qualities and constitution.

5.4 Transformation Premises

Another school of the preceding philosophical tradition is essential to be mentioned with reference to Kant’s early writings, namely anti-Wolffianism. The way of grounding Physical Influx presented by Kant in his early writings has experienced a strong influence of statements found in writings by Chr.A. Crusius, one of the most significant representatives of the anti-Wolffian school[25]. In many respects that was his writings which enabled the expansion and acknowledgement of Physical Influx[26]. The demolition of hierarchy of thinking and material substance is coherent with redefinition of such notions as ‘body’, ‘matter’ and ‘soul’ made by Crusius.

Another important figure is M. Knutzen (contacts with whom influenced young Kant a lot), although he is often considered among Wolffian thinkers. His treatise devoted to the research of soul nature and the struggle against materialists contains a number of abstracts that can be considered as a premise of changings made by Kant. The two-part structure of “Dreams” is similar to the structure of “Philosophical Treatise on the Immaterial Nature of the Soul” (1744). Although Knutzen stands up for the essential difference between soul and body, his reasoning nevertheless demonstrates the necessity of body which is a “dwelling” and an “instrument” of soul. Body has a particular influence on soul as it guides it in the material world. This influence has a limiting character though, as due to imperfection of the instrument soul can not act as deftly as it is prescribed. Souls differ a lot but act similarly as they are bound to bodies (which have a higher degree of similarity) and adjust themselves to them. The reciprocal impact is considered to be not immediate but is explained by existence of force as a common element (the similar strategy was elaborated by Crusius).

It can be seen that Kant’s early writings were influenced by three different views. The first one is Wollfianism that made the mind-body problem of current importance again and demonstrated a variety of solution strategies. Wolffianism inherited problems that had been aroused by Cartesian dualism and along with that referred to natural science as Wolff himself evidently supported Pre-established Harmony as the most proper solution. Therefore polemics within natural science (in the first place the polemic between Newton and Leibniz) influenced Kant as well, especially as concerns terminology and the range of considered physical problems. The third impulse was anti-Wolffian objections presented first of all in the writings by Crusius. The essentially different interpretation of such notions as matter, body, spirit, soul, substance or force provided a resource to recede from rigorous opposition of mind and body and enabled the spread and acknowledgement of Physical Influx. Thus, first two views determined in many respects themes and terminology of Kant’s pre-Critical writings and the third one supplied the conceptual resource for new attitude towards inherited problems.

6.      Transcendental Autonomy of Metaphysics

As a result, in Kant’s writings the identification of human body and other physical bodies is not necessary any more. Moreover, heterogeneity within human bodies becomes possible as well. Different impressions provided by body form the necessary condition of thought. Kant asserts that the influence of body on soul is inevitable. Soul is deeply embodied and rooted into matter and can not impact on the body as easily as the body impacts on it. While Leibniz just erases the boundary between body and soul claiming that existence of incorporeal spirits and inanimate bodies is impossible, Kant with such thesis makes the next step in dismantling the hierarchy of thought and physical processes[27].

Kant’s Critical philosophy presents the entirely different way of grounding the scientific character of metaphysics and does not concern psychophysical dualism. His transcendental philosophy presents other solution which enables conceptual and disciplinary sufficiency “to gain exhaustive acquaintance” [18, p. 102, A XIV] with the help of pure thinking, free of any experience. That means that although experience data are inevitable, we escape the dictates of objects that appear to our sensibility as they do not have the fundamental ontological status any longer. Therefore the whole complex of problems concerning the body is eliminated because all various physical bodies are seen as phenomena and such attitude provides their homogeneity. Although Critical writings present human being without a mind-body split, a certain duality still remains: human being can be grasped either as a phenomena and in this case it is possible to cognize him or as a noumena that is absolutely incognizable.

7.      Conclusion

All things existing in the world are divided in science of the new modern period into two unequal parts. On the one hand, there is human being who is endowed with reason and is able to cognize. On the other hand, there are all other things external to him as subjects of his cognition. Human being is grasped as thinking I that is detached, self-dependent and to a certain extent self-sufficient[28] as soul’s ability to be self-conscious is assumed to be its main feature. However, cognition of human nature remains to be an unsolved problem. Soul can be seen in two different perspectives. Firstly, it is liable to affects and passions and in this case its connection to body is emphasized inevitably. Secondly, soul is thinking substance and therefore human being is capable to cognize rationally. The second tendency appears to be a prior one and determinism is ascribed to the whole variety of physical processes (that means all these processes can be repeated and cognized). Determinism can not be ascribed to thinking I because of presupposition that nature of mind differs essentially from nature of subjects that are being cognized and does not comply with laws of nature discovered by it[29]. Rationalism postulates that all existing things can be cognized. Moreover, soul “… indeed is easier to know than the body” as exactly soul is something “… by which I am what I am” [6, p. 36]. Such conception leads to a contradiction as cognizing thinking I is not able to cognize nature of human being adequately. It appears not to be possible to disregard the connection of mind and body. Therefore researches of soul nature range between two poles, materialism and mysticism.