Introduction

I begin, however, with some remarks about reduction and reductionism. In my reconstruction of the position of both neuroscientists, it will appear that they move forth and back between reduction and reductionism. It is this moving forth and back which reveals underlying assumptions, even at the level of worldview. So, let us begin by clarifying what is meant with terms like reduction, reductionism and abstraction.

Abstraction, reduction, and reductionism

The remainder of this paper, therefore, will be devoted to the analysis of two texts of leading scholars in neuroscience and its philosophy; to the detection of background ideas and the implications of these ideas at the level of worldviews; and to the development of a conceptual framework that may help to evaluate new theories in cognitive neuroscience.

1. Churchland on reduction

   Patricia Churchland belongs to those very few philosophers who combine a thorough knowledge of neuroscience with philosophical acumen. She, moreover, is one of the strongest defenders of philosophical naturalism in our time. We will concentrate on a recent paper devoted to the reductionist account of consciousness.⁶

   Can neurobiology teach us anything about consciousness? The answer is affirmative. Neurobiology is—and will prove to be—one of the major sources of knowledge about consciousness. It is the cornerstone of the physicalist approach to mental phenomena. Physicalism is not an a priori insight, nor a faith, says Churchland. She considers it as a hypothesis, albeit a highly probable one. This ontological physicalism is coupled with epistemic reductionism. Reductionism is defined as: "..trying to explain the macro levels (psychological properties) in terms of micro levels (neural network properties)." In her earlier book Neurophilosophy, she qualifies this approach as a form of intertheoretic reduction.⁷ This qualification should not mislead us. Intertheoretic reduction as such is a primarily epistemic program. It has led to many conceptual and practical difficulties.⁸ Churchland's claims, however, reach beyond the epistemic domain. These claims, and their argumentation, can be summarized in three steps.

   The first step requires a translation of the language in which phenomena at a particular level A are described, into the theoretical language by means of which these phenomena are explained at level A.

   The next step consists of the reduction of theories at level A in terms of theories at some underlying level B. This intertheoretic approach is, in Churchland's view, a variant of explanatory or causal reductionism. This is because intertheoretic reduction is directed at explanatory unification. Theories are meant to explain a particular state of affairs. Intertheoretical reduction means that explanatory theories at level A are reformulated in terms of explanatory theories at level B. Ideally, this reductionist strategy will lead to explanatory unification. One mechanism or causal process will then explain both higher-level phenomena and lower-level phenomena. Explanatory reductionism exceeds, therefore, the claims of intertheoretic reductionism in that it aims at explanatory unification.

   This brings us to the third step: ontological simplification.⁹ Unification of theories will lead to the acceptance of a scientific worldview and to the rejection of so-called folk-psychology (common-sense psychology), according to Churchland. Explanatory reduction is, therefore, not an epistemic safe haven for those who wish to avoid the ontological claims of other reductionist strategies. On the contrary, it is a necessary part in the program of unification of theories on the mind/brain. The success of this program of unification is a measure of its truth. Coherence, thus, becomes the central criterion for truth.¹⁰

   Favorite analogies, in this respect, are the reduction of classical optics to the theory of electromagnetic radiation and the reduction of heat to molecular motion. Phenomena that had been analyzed with the conceptual tools of classical optics, became more intelligible after the establishment of electro-magnetic radiation. After this event, scientists understood that light is electromagnetic radiation. The same holds for theories about mental phenomena. These theories will be reduced to theories about neuronal processes. Churchland predicts that it will be proven, ultimately, that phenomena like perception and memory are certain neuronal processes. Successful reduction is the kind of reduction that leads to identification of the higher level with the lower level processes. As will be clear, this reformulation implies a much stronger version of reductionism than explanatory reductionism only. Explanatory reductionism restricts itself to the reduction of theories at level A to more encompassing theories at level B. Churchland's materialism, however, is eliminative, in the sense that it involves a "non-trivial revision and even replacement of existing high level descriptions by neurobiologically harmonious high level categories." Psychological properties, in this way, are understood as properties of the neuronal system.

   Churchland does not mean that a reductionist research strategy per se implies the adoption of a purely bottom-up strategy; nor does she mean that there is something disreputable about high level descriptions as such. It is, she says, wisest to conduct research on many levels simultaneously. However, the ultimate goal remains a revision of ordinary psychological language into the language of neurobiology. This revision would imply a destruction of folk-psychology.

   Churchland does admit that the ideal of a ‘complete’ reduction is utopian. Explanations are always incomplete. We should, therefore, perhaps eschew the expression ‘reduction’ in favor of ‘reductive contact,’ she says. However, this should not go so far as to repudiating the reductionist ideal. Folk-psychological experiences are appearances; they have a reality behind them. Brain activity is the reality behind the appearance of experiences. Laying bare neuronal reality does not in and of itself change experience; nor does it "allow me to view my brain as an MR scanner or a neurosurgeon." ¹¹ Characteristic of the working of our brain is that it allows ‘appearance/reality discoveries,’ i.e., that it has the capacity of laying bare what is really going on in the brain when a person has a particular subjective experience. The brain does not have a privileged access to objective facts. This holds true both for the external world and for the brain's model of the internal world. When we look at the sun, we do not know the sun as it is known by a physicist. In the same vein, we do not know ourselves, our inner private world, in the way a neurophysiologist may know the neuronal reality behind conscious states, according to Churchland.

2. Churchland on the reducibility of consciousness

   It is along these lines that Churchland attempts to account for both the apparent experiential reality of conscious states and the validity of the reductionist program. The brain does not have immediate access to realities behind experiences; however, it is the same brain that enables us to undo this imperfection. Neuroscience is, so to say, the great endeavor of a multitude of brains to remove the veils that brains have wrapped around themselves. As will be clear from this discussion, subjective experience is not a reality in its own right. It is rather an epiphenomenon of some underlying mechanism or process.

   In her discussion of criticisms of this reductionist approach, Churchland concentrates first on reservations that are based on common sense, intuition and use of language. Failure to imagine or to conceive that pain, perception and/or emotion consist in some pattern of activity of neurons in the brain is merely a psychological fact. It is a reflection of the current state of one’s ignorance. The same holds for all intuitions scientists and philosophers may have about how the world really is. These intuitions do not say anything deep or metaphysical about reality, nor do they say something decisive about the empirical or logical possibility of the reductionist approach of the phenomena of consciousness. Dooming the reductionist research strategy because of the categorical confusion, which threatens potentially any inter-level reduction, does not seem to impress Churchland very much. In every age scientists have said ‘funny things’ about the world. To say that the earth is a planet and that it moves, sounded funny in Copernicus’ days; to say that physical space is non-Euclidean and that parallel lines may converge, sounded funny up until some sixty years ago. It is, in other words, "rather far-fetched to suppose that intuitions in the philosophy of language can be a reliable guide to what science can and cannot discover about the nature of the universe".¹²

   I think this rejoinder does not make the point properly. First, some would argue that the examples just given do not concern clear-cut inter-level, but intra-level types of reduction. That this may not be self-evident is a reflection of the fact that there exists some confusion in the literature about what the notion of ‘level’ could mean. Many scientists, Churchland included, view the hierarchy of levels as a constellation of structures which are ordered from macro- to micro-entities; they see it as a hierarchy of part-whole entities in which the parts at a certain level become wholes at the underlying level. According to this view there exists indeed a reductive relation between, roughly speaking, heat (as measured by a thermometer) and molecular motion; and between classical optics and the laws of thermodynamics. However, from another point of view, these are only intra-level reductions. For, the reductive explanations just mentioned remain explanations at the level of physics; and the predictions that are based on these explanations can be substantiated with the tools of physics. ‘Level’ is referring, here, to the qualitative distinctiveness of aspects or modalities of reality; the term level does not refer to entities here, but to modes of being or modes of functioning. It is this qualitative distinctiveness between modes of reality—and their underlying structures—that accounts for the fact that explanations of mental events, for instance the reasons for one's thoughts or feelings, qualitatively differ from the explanations of the neural machinery in which these thoughts and feelings are embodied. These explanations are typically biological and refer, for instance, to a particular neuroendocrine or neurophysiological process. From these few preliminary remarks, it may be gathered that the confusion between entitary and modal-functional points of view bears relevance to the distinction between reduction and reductionism; and between abstraction and reification. When the modal analysis of an aspect of reality is fundamental in the process of abstraction, then the entitary reformulation of this modal (or functional) point of view may become a first step into the direction of reification and undue substantializing. I will return to this point in the final section.

   There is another reason for questioning Churchland's rejection of the appeal to intuition, common sense and ordinary language. Churchland apparently thinks that intuitions derived from common sense and ordinary language may, and in fact do, preclude all kinds of reductive research strategies. This is, however, a misperception. Defenders of the categorical distinctiveness of psychological and neurobiological concepts do not, in general, resist reduction and/or abstraction. Most of them will acknowledge that their position is compatible with the investigation of phenomena at a certain level with the conceptual and experimental tools from lower levels. They feel not coerced to ontological reductionism when they study visual perception with the tools of radiology, neurobiology and molecular biology.¹³ This is, however, precisely what Churchland suggests. She, in other words, incorrectly identifies legitimate (epistemic) reduction with illegitimate (ontological) reductionism. One may wonder why this is. The only explanation I can imagine is scientism; i.e. an almost unshakable belief that ultimately science, which almost by definition is bound to reductive strategies, will provide the most solid answers on our questions about the universe. In spite of the inherent fallibility of scientific theories and hypotheses, the truth and trustworthiness of propositions based on scientific evidence rises far above common sense and linguistic convention.

   Of course, this puts a heavy burden upon eliminative physicalism as a scientific program. Granted that there is not, and perhaps never will be, a complete reduction, which degree of success or lack of success must there be to count as confirmation or refutation of this program, especially in the field of consciousness? Churchland's position with respect to these questions becomes clear in her discussion with Searle and Dennett.

3. Churchland’s discussion with Searle and Dennett

In her own account of consciousness, Churchland concentrates on visual awareness and visual perception. She combines the work of Crick, who sketched the outline of a theory on the temporal binding (or synchrony) of output responses of neurons relevant for visual perception; the hypothesis of Llinas and co-workers, who assume that there are two pairs of coupled oscillator families connecting the thalamus and the cortex, one providing the sensory and modality-specific content, the other providing the integrating context; and the ideas of Damasio, who says that body-representation provides the scaffolding for self-representation, which in its turn is the anchor point for awareness. Without such an anchor point there is no ‘point of view,’ a representation of oneself into the known world. This ‘no awareness without self-awareness’ (in the sense of self-representation) echoes Kant in his comments on Hume. As will be clear, this self is not transcendental, but neural. It is not considered as an idea that necessarily has to be assumed in order to make knowledge of the empirical self and of the world possible. On the contrary, there is something behind this self and the knowledge of itself: the brain. Both the self-representation and the representation of the world are ‘produced by’ the brain. The brain is the condition that ‘necessarily’ must be presumed in order to make the self and its knowledge possible. The empirical becomes quasi-transcendental. If anything is clear from this account, it is that the brain is viewed as a self-sustaining entity; not as a part-structure within the body, not even as an organ; but, it seems, as a substance which finds the possibilities of its existence within itself (and its causal history).

Eric Kandel: Toward a new intellectual framework for psychiatry

1. Kandel about the contribution of molecular biology

   As a second example of a text of a leading scholar in the field of neuroscience, I have chosen a recent article of Nobel prize winner Eric Kandel, titled A New Intellectual Framework for Psychiatry.²¹ Kandel and his group are well-known because of their imaginative experiments with the marine snail Aplysia, in which they managed to unravel molecular biological correlates of behavioral states resembling anticipatory anxiety (in response to a classical aversive conditioning paradigm) and chronic anxiety (in response to a long-term sensitization paradigm). This background of experimental work in the seventies and eighties is important to understand Kandel's position in the nineties.

   Kandel first sketches the diverging ways of general medicine and psychiatry. After World War II general medicine gradually evolved from a practicing art toward a scientific discipline based on molecular biology. Psychiatry, on the other hand, abandoned its roots in biology and capitulated to the anti-scientific and dogmatic climate of post-war psychoanalytic thought. However, from the late seventies and early eighties the brain sciences have become more and more important and today's psychiatry cannot even be thought of without acknowledging the enormous contribution of molecular biology and basic pharmacological research to the understanding and treatment of patients with psychiatric disorders. The divergence has, thus, altered into convergence.

   Does this imply a reduction of psychopathology to biological dysfunction? No, says Kandel, the picture is more complicated. For, "(w)hen it comes to studying mental function, biologists are badly in need of guidance. Psychiatry, cognitive psychology, and psychoanalysis can define for biology the mental functions that need to be studied for a meaningful and sophisticated understanding of the biology of the human mind".²² Psychiatry derives its scientific basis from molecular biology; however, molecular biology is in need of a careful and valid delineation of all kinds of behavioral dysfunction. Therefore, both disciplines are complementary.

   However, how does the study of mental function relate to the investigation of brain disturbances? To answer this question, Kandel formulates five principles, which could serve as, what he calls, a ‘new intellectual framework for psychiatry.’ These principles reflect current understanding of biologists of the relation of mind to brain. I mention the first, and most important, of these principles and give some comments²³:

   "All mental processes," Kandel writes, "even the most complex psychological processes, derive from operations of the brain. The central tenet of this view is that what we commonly call mind is a range of functions carried out by the brain. (…) As a corollary, behavioral disorders that characterize psychiatric illness are disturbances of brain function, even in those cases where the causes of the disturbances are clearly environmental in origin." Kandel calls this principle the ‘basic assumption’ underlying neural science. "Specific lesions produce specific alterations in behavior, and specific alterations in behavior are reflected in characteristic functional changes in the brain" (all italics added).

2. Kandel’s ambiguity: between psychophysical identity theory and epiphenomenalism

How is it with the empirical side? How does Kandel's conceptual/ontological ambiguity relate to science’s task of explaining a particular process? Kandel’s use of terms like ‘production’ and ‘determination’ could be understood as denoting certain processes, of which the order of successive events is interpreted as a causal history, i.e., as a process in which the events have causal power and in the course of their development produce higher level phenomena. I think this is not what Kandel means. I mention this solution, because it is a rather popular one in evolutionary accounts of interlevel relationships. Another interpretation could be that terms like production and determination refer to ‘lawful regularities’ or ‘principles’ that hold for the process under investigation. However, insofar as these processes do entail interlevel relationships, this interpretation will not bring us any further; instead, it brings us back to old debates on so-called bridge-laws; a debate that was lost by the advocates of bridge laws, as will be known.

1. Summary

   We started our investigation by reviewing the tensions between reduction (or abstraction) as a primarily epistemic endeavor and reductionism as a program with, ultimately, ontological pretensions and claims. We noticed the importance of metaphors and images in opening-up a field of science. Think, for instance, of the developments in biology after the discovery of DNA as a ‘carrier of information.’ Extending the meaning of concepts beyond their original domain almost automatically leads to a metaphorical use of these concepts (DNA molecules do not really communicate). It is in the metaphorical use of scientific language that one may find the worldview, hidden or not. In addition to this extension of conceptual meaning worldviews also enter into scientific language by the unjustified substantialization and reification of abstract concepts.

   We saw how entities are often confused with modes (or levels) of existence and how this may result in unclarity and reification. Psychophysical dualism and dualist interactionism may be seen as a result of the unjustified belief in the independent existence of mind and of body as (quasi-) substances. The modal aspect—mental functioning as a mode of functioning that qualitatively differs from biological functioning—is substantialized and changed into a mental substance or a mental entity called ‘The Mind.’ Psychophysical identity theories, on the other hand, run the risk of being transformed into one or another form of monism. This occurs when the nature of the ‘common ground’ of different forms of functioning is defined in terms of one particular scientific discipline, such as biology.

   In the remainder of this paper, I will attempt to give a more systematic account of the notions and the ideas we have come across. What will be said, relies on the seminal work of the Dutch philosopher Herman Dooyeweerd (1894-1977), especially on his theory of entities (or individuality structures).²⁸ Dooyeweerd, however, has never published extensively on philosophical anthropology and/or on neuroscience; so we have to rely on the other works and extrapolate from these studies to the field of neuroscience and philosophical anthropology. In what follows, I will present my own elaboration of ideas of which the basis can be found in the work of Dooyeweerd. The aim of this sketch is to provide a systematic framework, which can be used as a frame of reference in the evaluation of empirical models and theories. It should not be considered as a blueprint or a dogmatic doctrine, but as a fallible attempt to provide some conceptual clarity in the interpretation of neuroscientific findings.

2. The fundamental distinction between entities and modes

   Let us begin with the distinction between entities and modes. Entities are, roughly speaking, things, events, and states of affairs. Things, events and states of affairs can be recognized as individual entities; they can also be identified as entities belonging to a certain class or family. They have, in other words, both an individual and a structural side. The tree at the corner of the street can be identified both as this particular tree of which I have some dear, personal recollections, and as the tree I recognize as belonging to the class of oaks.

   The distinction between modes and entities is important, as we saw, to correct the popular view that the universe is built up as a hierarchical ordering of part/whole-structures with an increasing degree of complexity. Complexity is simply not enough to do justice to the qualitative diversity of the structures within the universe. Part-whole ‘holism’ easily leads to reductionism, because either whole and parts are both conceived as the product or result of underlying and more basic processes (microphysical processes, for instance); or whole and parts are seen as determined by the laws and regularities of the largest whole, i.e. the universe and/or the principles of cosmology.

   Modes, or modalities, or aspects, are conceived by Dooyeweerd as fundamental and universal modes of being, or modes of functioning. This concept of mode (modality, aspect) is very abstract. It refers to the "most basic kinds of properties and laws exhibited by the things, events, relations, states of affairs…".²⁹ These kinds of properties must be distinguished from the notion of type (of events, things, or states of affairs). Types are types of things (events; states of affairs) and, therefore, associated with the domain of entities.

   Modalities are universal modes of being of entities. Therefore, statements about the functioning of a particular entity are typically statements with a universal intent: these statements refer to a particular lawful pattern of properties in the modal functioning of that entity.

   Examples of these modalities are (in order of succession): the numerical, the spatial, the kinematic, the physical, the biotic, the psychic, the logical, the historical, the lingual, the social, the economic, the aesthetic, the jural, the ethical and the pistic modality. The discovery of this succession is based on the painstaking examination of the way in which the modal functioning of different types of entities is organized. Every entity functions, basically, in all modalities. That is to say, every thing, event, and state of affair—and, we may add, person—has properties in all known aspects of reality. This means that the aforementioned tree functions in a more-than-biotic sense--for instance, also in a psychical, or in a juridical, or in an aesthetic sense.

   This may sound odd. However, it is much less peculiar when another distinction is taken into account, i.e., the distinction between functioning in a passive and in an active sense.³⁰ One could say, then, that the tree actively functions in the numerical, the spatial, the kinematic, the physical and the biotic modality; which means that its functioning in those aspects is necessary for being a tree and that this functioning is not dependent on the activity of another entity or agent, but depends on the tree itself; and that it functions passively in the other ‘higher’ aspects; which means that its functioning in those aspects belongs to its possibilities, but that, on the other hand, the actualization of these possibilities is not a prerequisite for being a tree. Therefore, we may say of the tree that its odor can be smelled (psychical), that its existence can become the subject of a legal procedure (jural); and that its beauty may inspire the artist's imagination (aesthetic). All these properties are, however, potential qualities; qualities, in other words, that can be opened up; their opening up is not a necessary condition for the tree being recognized as a tree (although the odor of a tree may help to identify which kind of tree it is we smell).

   There are two reasons why this distinction between functioning in an active and in a passive sense is so important. The first reason is that it counteracts the common idea that the ‘passive’ modes (or object-functions) in which trees function and the properties belonging to these passive modes, are only subjectively ascribed to, or projected into, the tree by the observer—as were these modes or functions not properties of the tree itself, the ‘real’ tree, but ‘merely’ properties in the imagination of the observer or epiphenomena of the tree as a physical/chemical reality. Dooyeweerd, in other words, adheres to a realist interpretation of what the empiricists called secondary qualities. The fact that one can smell a tree, is a property of the tree itself—of its ‘smell-ability,’ so to say.

   The second reason for distinguishing between the two types of functioning is that the difference between functioning in a passive and in an active sense—when applied to a large number of entities—is indispensable to make ontological distinctions within the various realms of entities. To mention only one obvious example: the distinction between lifeless entities, plants, and animals can be defended, now, by saying that lifeless things (such as chairs) function actively in aspects up to the physical (and passively in all the higher aspects); plants (such as trees) in all aspects up to the biotic; and animals (dogs) in all aspects up to the psychical (dogs have instincts and emotions).³¹

3. Part-whole relations and the notion of enkaptic interlacements

   So far, we have distinguished between modes and entities; and between active and passive functioning in the various modal aspects. Modes point to universal modes of being or functioning; modal formulations are often law-like propositions. Entities have both an individual side (they are exemplars) and a universal side (as types, or classes). Entities function in all modes, partly in an active, partly in a passive sense, depending on the nature of the entity. One of the refinements of this theory entails the notion of qualifying and foundational functions (aspects, modalities). A thing may be qualified by a function, higher than the highest active function (mode); chairs around the table, for instance, may be qualified by their social object-function. Their being used (passive) in social interaction qualifies them as chairs. However, the chairs are not themselves functioning as social agents. Object-functions, in general, require another thing or agent to interact with; it is in this interaction that the object-function (or passive function) is disclosed.

   Now, we must enter the subject of (a) part-whole relations, (b) the enkaptic interlacements between structural wholes, and (c) the enkaptic structural whole as a structure binding together a number of part-structures. Enkapsis literally means incapsulation.³² The term points, roughly, to the ‘interwovenness of part-structures into a larger whole without loss of relative independence of part-structures.’ The crucial issue is that ‘independence’ should not primarily be understood, here, as independent existence as an entity, but as independence in a modal or functional sense, i.e. as the independence of the internal destination, or the internal qualifying function, of the part-structures. The marble in the famous statue called the ‘Hermes of Praxiteles’ remains, as a part-structure, physically qualified. The marble is enkaptically bound within the structure of the whole—the ‘Hermes of Praxiteles’ as a sculpture, i.e. as an aesthetically qualified entitary structure. The same holds for the molecules in a cell, and for living organisms and their Umwelt.

   We can now understand the difference between part-whole relations and enkaptic interlacements. In the part-whole relation, parts do not retain their internal qualifying function; the qualifying function (or qualifying mode) of the part is identical to the qualifying function of the whole, from which it is derived. An example of a part-whole relation is the relation between organs and the organism as a whole. Organs differ with respect to their function within the body, but from a more general (modal) point of view, all these functions are meant to support the fundamental biological properties and goals of the organism: homeostasis and reproduction, for instance.³³

   One further step is the distinction between enkapsis as such (enkaptic interlacements as such, without a superordinate or encompassing entitary structure) and enkaptic structural wholes. The latter differ from ordinary forms of enkapsis, because the parts are bound together in a larger whole which has itself also an internal destination and conforms to certain structural principles, whereas the part-structures obey their own internal structural principles. The Hermes of Praxiteles is an example of such a structural whole, in the sense that the physical material (marble), as a part structure, keeps functioning according to the (physical) laws for pieces of marble in general, and at the same time is bound and determined by its functioning within the larger whole, i.e. the statue as a product of the artistic imagination, a product that is qualified by its aesthetic (object-, passive) function.

   I think, we should be aware of the radicalism of this position. Dooyeweerd’s approach entails, among others, the idea that the difference between the physical part-structure and the sculpture as an enkaptic structural whole cannot be found in the physical material itself; for instance in its microstructure.³⁴ There is no single aspect of the structural whole of the statue as an aesthetic object that is not at the same time also physical. On the other hand, there is no single aspect of the marble which does not also possess an aesthetic meaning. This position, nevertheless, does not amount to either a psychophysical identity theory (because of the qualitative diversity of modal aspects and the relative independence of the internal structural principles of the part-structures) or to a kind of epiphenomenalism in which the mental qualities appear as the result of a particular ordering of the physical material; nor to a dualism of substances or properties, or to a view in which the relation between two co-varying levels is conceptualized as a relation of supervenience.

4. Brain functioning

   What is the relevance of these distinctions, and of this position, for the study of the brain? One of the thrusts of this paper is to warn of an almost ineradicable thought-habit, i.e., to identify the brain as a concrete, morphologically discernable entity with the results of scientific research into the biotic (and other) functions of the brain. This identification, in fact, implies reification. For, from the modal (or functional) point of view the brain is studied as an ‘organ’ of which the functions obey certain biotic regularities and laws. However, the identification of this modal point of view with the brain as tangible and visible entity means that two conceptual gaps are neglected: the gap between the modal and the entitary point of view; and the gap between entity in a structural and entity in an individual sense.

   Modern neuro-imaging techniques are especially interesting in this respect, because they are highly suggestive for the tangibility of what in fact belongs to the structural features of brain functioning. Looking at the different colorings of the MRI-pictures of schizophrenic patients and normal controls, one is tempted to say: "We now see what schizophrenia is." However, there are many levels, structures and distinctions that are passed over in this sentence. Clinicians, for instance, easily forget the determining role of mathematics in the geometric representation of the brain. We also should not forget that the term ‘brain’ is an unqualified and undifferentiated word that belongs to ordinary language. When transposed to scientific discourse, this term may become a carrier of many different meanings, some of which with clearly substantialist connotations.

   In response to these all-too-easy identifications, I would like to plead for a view in which the brain as a concrete, visible part of the human body is seen as responding to, and operating within, a number of part-structures; and in which these part-structures are seen as functioning within the structural whole of the human body.³⁵ To give an idea of the kind of part-structures one might think of, one could begin by discerning a physical-chemical part-structure, a biotic part-structure, a psychical part-structure and an actstructure; part-structures of which each ‘lower’ part-structure is encompassed by the next, ‘higher’ part-structure; the actstructure encompassing them all. Each encompassed or underlying part-structure functions in a foundational sense within the higher part-structure, the physical-chemical within the biotic, the biotic within the psychic, etc. The part-structures are qualified by the function or mode, which is used to denote them. The actstructure is an open structure in the sense that it has no fixed qualifying function or mode, but may conform to a wide variety of functions and/or modes. It defines the mode to which a particular act of a person conforms. Which mode prevails depends on the acti-vity of the person and the context in which this takes place.

   Briefly stated, there are three ways to resist the all-too-easy identification of the brain as concrete ‘organ’ with what neuroscientific investigations say about the brain.

   (1) The modal point of view should be sharply distinguished from the entitary point of view. In other words, the functioning of the brain according to the laws and regularities of a particular modal aspect should be distinguished from the functioning of the brain as an entity. The modal term denotes a particular aspect of the functioning of the brain; whereas the entitary term refers to the thing-like structure(s) of the brain. Of course, both the expression ‘modal function’ and the expression ‘entity’ are used in an abstract sense here. What one actually investigates are always—except in certain post-mortem cases—brain processes, i.e., molecular, neurochemical, and neuroendocrine processes. In the laboratory one never encounters brains as such, but brains involved in all kinds of processes. This brings us to the second distinction.

   (2) What just has been said seems trivial. However, the term process may obscure the important difference between what is lawlike about a particular brain process and the process itself, as a sequence of concrete events. Propositions about the lawfulness of the brain process are of a different order, compared to propositions describing this sequence. I emphasize this, because there is a rather strong tendency in philosophy of science to blur this distinction. The explanation of a particular state of affairs is, then, limited to the description of the causal history of that state of affairs or to descriptive generalizations applicable to the sequence of events leading to that particular state of affairs. Confusingly enough, these descriptive generalizations are sometimes called ‘causal laws.’ In other accounts, laws are viewed as laws of the models providing the conceptual framework for these descriptions, and not as laws governing real processes. According to this approach, laws are merely instrumental.³⁶ In all these approaches laws are denied to have existence in reality; they are either something in the mind of the scientist or do not exist at all (at least not as something which ‘holds for’ a particular piece of reality). Because the lawfulness of reality, ultimately, cannot be denied, elements of lawfulness return, but now as qualities inherent to reality itself (as hidden powers, encompassing principles, basic building blocks with evolutionary potential, etc.). Determinism is not as far from us as some of us would be inclined to expect.

   (3) Finally, reification is also precluded if the notion of enkaptically interlaced part-structures is taken into account. These part-structures obey their own internal structural principles, each of them having their own qualifying function; whereas all are encompassed within the structural whole of the human body. ‘Body’ should be taken here to denote the human person in a full sense, including the functioning of the person in social, economic, legal, aesthetic, moral and religious relations. These ways of functioning are all corporeal, according to Dooyeweerd, in the sense that they are nothing apart from human corporeality.

   When these views are taken seriously, they imply that each part of the human body, the brain included, at the same time functions in all four part-structures. This means that the brain not only functions within the physical and biotic part-structure, but also in the psychical part-structure and in the act-structure.

5. Is the brain an agent?

From this account it might be predicted that the ‘higher’ the part-structures that are involved in a particular human activity, the wider the context neuroscientists should take into account in order to study the brain correlates of that particular activity. Even at a biological level the context widens when more complex and typically human activities are studied.