Ernst Mach and Daniel Dennett: Two Evolutionary Models of Cognition Csaba Pléh Department of General psychology, Eötvös Loránd University, Budapest
The paper compares the interpretation of the relevance of evolutionary theory for epistemology and psychology given by Mach and Dennett. Both authors believe that evolution gives a hypothetical interpretation for our mentalistic concepts. They are used because they work. This pragmatic view is most clearly seen in their conception of self. They both claim that the self rather then being a stable starting point is a working hypothesis. For Mach the essential element behind the concept of self is our body image, while Dennett takes a narrative view: the self is a postulated narrative gravitational point. Their similarities are not entirely accidental. There are some mediators between their respective ideas especially Karl Popper who has taken up from his Viennese heritage the epistemological role attributed to evolutionary concepts.
Evolutionary traditions and present day cognitive trends
In the present stage of development of cognitive science the functionalism of the formerly received view that had no clearcut biological interpretation seems to fade away. Several types of biologically oriented interpretive models move to center stage. In this context it is becoming quite relevant and interesting to search for historical parallels and inspirations of biological interpretive models in the same way as it was done for computational models with reference to Kant, Hume, and even Plato (see about some of them Brook, 1994, and the volume edited by Smith, 1990), not to talk now about Cartesian models.
One of the leading contenders for the role if not for a New Synthesis at least for a new inspiration for research is the evolutionary conception of Daniel Dennett (1987, 1991, 1994). Some of his basic ideas to concern us in this respect might be summarized as follows:
i. Some of our cognitive achievements are related to attitudes. To stances towards the world like the intentional stance (Dennett, 1987) that are 'soft' in the sense that they can be given an instrumental interpretation.
ii. We are entitled to use them because they work pragmatically.
iii. This pragmatic feasibility is related to the fact that they were formed in our evolutionary history (Dennett, 1991a, 1994).
iv. There are no mysterious or essentialistic static points or preset certain goals neither in the structure and processing of the mind nor in its evolution.
v. Self and consciousness are not fixed starting points and identifiable inner places. Rather, they are shifting abstract entities like gravitational centers which are useful for our orientation.
I intend to show that a point of view similar to this both in its structure and content was formed a hundred years ago in the first enthusiasm over the philosophical relevance of evolutionary theory. It has become customary today to rediscover the importance of evolutionary theory for turn of century psychology and philosophy. We have a constant emphasis in the work of authors like Richard Rorty (1982) of the role of the non-finite nature of our human universe and its relationship to evolution and democracy in pragmatic authors like Dewey (1910). There is a well known continuous albeit socially many times challenged tradition of looking at individual differences from an evolutionary perspective. There is a third historical trend, however, that deserves some attention. This is the early evolutionary interpretation of questions of epistemology and mental organization. This tradition entails a belief in the evolutionary interpretation of our internal representations, preferences, and even concepts. Historically two types of approaches can be observed in this field. One was the straightforward motor adaptationist interpretation of mental life. The mental world in higher animals would be a direct derivative of motor adaptations. This showed up in the early motor theories of perception and consciousness, in authors like the French Théodule Ribot with his motor theory of perception, the Russian Sechenov with his notion of inner inhibition (all mental would be of a reflex nature with the efferent part of the reflex inhibited) and the Hungarian Eugene Posch with his motor theory of the mind inspired by Spencer. The interest and importance of Ernst Mach for evolutionary theories of cognition lies partly in the fact that he tried to give a Darwinian interpretation of mental life without binding it to a peripheral motor theory. For him the inner world, the world of experience is a starting point, and he intends to show that this inner life can be given a non essentialist functional interpretation. Leszek Kolakowski (1968, p. 155) in his treatment of positivist philosophy gave a summary of the views of Mach and other empiriocriticists in a way rather similar to the characterization of Dennett we started from:
we are especially struck by the following features [in Mach] : (1) the philosophical destruction of the subject; (2) the biological and practical conception of cognitive functions, reduction of intellectual behavior to purely organic needs, and renunciation of 'truth' in the transcendental sense; (3) desire to get back to the most primitive concrete datum, to a 'natural' view of the world not mediated by metaphysical fictions.
Ernst Mach was a key figure in first trying to interpret Darwin with reference to issues of epistemology and the then new born experimental psychology of consciousness or content of which he was an early champion. Mach the archipositivist believed in the unity of science. For him, however, this was based on the unity of experience, on the fact that the starting point for all sciences (physics and psychology included) is experience taken neutrally. (Blackmore, 1972 shows what influence this had on Russell's neutral monism.) There is no principal difference between psychology and physics: all start with experience, he claims in his famous "antimetaphysical remarks" (Mach, 1897), but in considering them in themselves we are doing physics, while in interpreting them as related to the body we are studying sensations. Physiological psychology in this process becomes a part of physics. There is no conceptual boundary between the two. This idea was not entirely new. Varieties of this duality of attitude approach to the relations between traditional natural science and psychology were provided by Wundt and his followers. Interestingly enough, while Mach basically never quotes Wundt, some of the most systematic students of Wundt, like Külpe and Titchener rely heavily on Mach in their systematic treatments. (See Blackmore, 1972.) "The traditional gulf between physical and psychological research ... exist only for the habitual stereotyped method of observation. A color is a physical object so long as we consider its dependence upon its luminous source, upon other colors, upon heat, upon space and so forth. regarding, however, its dependence upon the retina ... it becomes a psychological object, a sensation. Not the subject, but the direction of our investigation, is different in the two domains" (Mach, 1897, 14-15 pp.).
This implies an interesting attitude towards one of the basic debated issues in contemporary cognitive studies: the issue of qualia. On the one hand Mach would align himself together with those who deny that qualia pose any special problem (he would go along with Dennett, 1991a) but his claim for unity would be based on a neutral but still inner, experiential unity: qualia are not a special issue because physics also starts from inner experience. "Consciousness is not a special mental quality or class of qualities different from the physical ones; nor is it a special quality that would have to be added to physical ones in order to make the unconscious conscious... Consciousness consists not in a special quality but in a special connection between qualities" (Mach, 1976, p. 31)
This monistic attitude is combined by Mach with a thoroughgoing Elementarism and sensationalism. "all bodies are but thought-symbols for complexes of sensations.." (Mach, 1897, p. 23) he warns the physicist. "the elements form the real, immediate, and ultimate foundation... For us, colors, sounds, spaces, times,... are the ultimate elements..." (ibid, p. 23).
Recently, Porter (1994) pointed out again that the antiessentialist moment and the alienation form any kind of "substantialism" in Mach lead to further developments towards a social view of science in the work of Pearson (1892). Pearson, beside proposing a view of science that replaces causality with correlation, also emphasized that the scientific enterprise should lead to a decentration of the knowing subject, and to a treatment of knowledge only as a cross section of impersonal social factors.
Economy as an Explanatory Principle of Reduction and its Relation to Evolution
That part of Mach, i.e. his Elementarism and the kind of pre-phenomenological but still phenomenal monism is fair enough. It has some negative consequences for his view of the physical world. As Capek (1968, p. 189) put it, he is too certain in the phenomenal view of the world and too Spencerian in his attitude, that is why he is unhappy with the "non-phenomenalistic features of 20th century physics". This attitude would be reconcilable with a general (uninterpreted) positivist unified science view. Mach, however, enters evolutionary considerations to the scene in several ways. His "biological view of knowledge" basically holds that "the cognitive functions of the human mind are not static and immutable entities but, like all other physical and physiological features of man, are subject to gradual growth and development" (Capek, 1968, p. 172). The key to his evolutionary deductions is his Principle of Economy. That is the one William James has such a high regard for him. Interestingly enough this is the aspects where Mach was not a neutral pragmatist: for him, it was essential to connect pragmatic considerations to his biological views (Blackmore, 1972, 126-28, 176-77 pp.).
Blackmore (1972, pp. 173-179) differentiated 11 different uses of this principle by Mach (see also Kallfelz, 1929). Basically the uses relate either to economy in doing science, or to economy in our everyday cognition. Whatever concepts work in the mind they work because they pay off, they are more economical then other solutions would be. In order to connect this to evolutionary theory you must of course have an underlying presupposition. "Mother Nature" is not only a Blind Watchmaker but a stingy one as well, she never does anything superfluous. This effort to connect economy to evolution is conceptually a non-trivial move. As contemporary arguments about the non-optimal nature of the design of the living indicate the structure of living beings is not optimally economical from an engineering perspective (see for a summary Clark, 1989). The commitments of Mach to connect the two are conceptually weak, but they lead him to some interesting propositions regarding the evolutionary origin of some specific cognitive tools.
According to Mach, our concepts that are treated in a realistic way are somehow economic shorthand symbols. The adaptationist principle is part of not only biological evolution in the strict sense but the world of cognition or the mind as well. Our mental world works with hypotheses that are accepted because they work, they lead to acceptable solutions. Mach is among the first authors to make the idea of selection enter the mental realm with his peculiar use of the economy principle. "Physics is experience, arranged in economical order" (Mach, 1910, p. 197).
Mach goes further, however. Economy as a pragmatic evolutionary criterion is not only true for our everyday concepts, but it is the driving force behind scientific progress as well. The writer Robert Musil (1982) summarized this aspect of Mach rather clearly in his dissertation on Mach. He even pointed out some troubles that can be projected to the contemporary pragmatist interpretation of the economy principle. One interpretation would be that it is a description of scientific progress, the other is a principle of epistemological skepticism and relativism. "There would then be no solid, so to speak absolute truth but only truth which is relative in the sense that any opinion will count as true provided it fulfills its purpose of providing adequate orientation. In other words, there is no truth at all in the authentic sense but on a practical convention contributing to self-preservation" (Musil, 1982, p. 26). This uncertainty, this lack of a stable reference point was the most troubling feature of Mach for Lenin (1927). Whenever he mentions the principle of economy he downgrades it as a circular and subjective notion. It is very telling that this supposedly doctrinaire materialist book never mentions evolutionary theory, neither in connection with Mach nor in other contexts.
The Darwinian interpretation of the Principle of Economy in Mach shows up most clearly in two respects. In several of his technical writings - including the Contributions to the analysis of sensations, he presented an evolutionary image of several aspects of sensory representation, including colors and dimensions of space perception. The logical structure of his argumentation is rather interesting even for present day cognitive studies. In accordance with his general monistic commitments, he believes in a total psychophysiological parallelism: for each aspect of sensory experience there is a corresponding physiological structure. That structure has to be explained by evolutionary considerations, on its turn, as an adaptation to the environment. Thus in principle Mach claims a dual biological anchorage for the mental: not only a short range physiological, but a long range evolutionary account as well (Mayr, 1982). This would explain several factors in human intellectual history. Our first interest in geometry e.g. would come from the structure of our nervous apparatus dealing with space. And in that apparatus the primacy of straight line e.g. would be explained not by frequencies in individual experience but by the fact that the straight line gives minimum deviation from the mean values of depth. Seeing straight lines would require the least effort and thus would comply with the Principle of Economy.
As for the course of research, we might very well start from "teleological considerations" about the goals of the organism, and so on, but we have to keep in mind that this does not give us yet a causal explanation. The final causal explanation must always be a physical one that has to take over from teleological and historical considerations (Mach, 1897, Chapters IV and V.). This image of the relationships between levels of organization and levels of explanation resembles in many aspects the relationship between "the stances" as proposed by Dennett (1987), and some of the adaptationist interpretations in "evolutionary psychology" (see the volume edited by Barkow, Cosmides, and Tooby, 1992). In later editions of the Analysis, and in his work on the psychology of discovery (Mach, 1976) he is very considerate of the work of Lloyd Morgan (1894) the comparative psychologist who's famous Canon (if you can explain some behavior with a simpler mental organization, you are not entitled to attribute the more complicated one to the given species) has become an extraordinarily important version of the economy principle both in doing science and in creating behaviorist psychology.
Mach also takes an adaptationist, biological view of science. In his acceptance speech as Rector of Prague University he claims that everything is part of a universal process of evolution with positive connotations of progress. "We are prepared, thus, to regard ourselves and every one of our ideas as a product and a subject of universal evolution" (Mach, 1910, p. 235).
There is a unified science due to the common subject matter. But there is a unity over simple biological adaptations and science as well due to the attitudes represented. "Expressed in the most concise terms, the task of scientific inquiry consists in adapting thoughts to facts and thoughts to one another. Every beneficial biological process furthers self-preservation, and hence is a process of adaptation... For the physical, biological behavior of living beings is co-determined, and supplemented, by the inner processes and thinking." (Mach, quoted from Kolakowski, 1968, p.145). There is so much unity of approach that in an ironical footnote Mach himself (1897, Chapter 1, p. 15) reminds us that due to its adaptive nature our thought is sometimes at the mercy of our most worldly interests such as nationalism or class interest etc.
There is one aspect of the evolutionary ideas found in Mach that specifically deserves mention. That is the idea of an intentional stance applied to our fellow humans. The whole issue of using intentional, design related (teleological) and causal explanations in general is discussed in detail in the Analysis (Mach, 1897, pp. 68-69.). In the same book he argues in the first chapter for an analogical knowledge of other minds.
In his popular scientific talks he elaborates this line of thought further. "We predict in thought the acts and behavior of men by assuming sensations, feelings, and wills similar to our own connected with their bodies" (Mach, 1910, p. 207). The above attributions do appear early on: "every child unconsciously accomplished it" (ibid, p. 208). This would certainly place him along the so called simulation theorists today regarding the origin of our theories of mind in contrast to the 'theory theories' but it still shows how important the whole issue of what is the basis for attributing mentality was for Mach. In comparing him to Dennett the latter author along with his moving away from the centrality of the Ego would treat even self-knowledge in an inferential way rather then to be a starting point as it was for Mach. (I ow this observation to György Gergely who has written influential experimental and conceptual papers on the present status of these debates e.g. Gergely, Nádasdy, Csibra, and Bíró 1995).
The dissolution of the Ego concept Mach returns several times to the Humeian issue of the disappearance of the Ego as a stable starting point. He treats this both from an internalist perspective, as an impressionist image of the mind: the mind is but "a bundle or collection of different perceptions" (Hume) (see a philosophical presentation of this aspect of Mach in Kolakowski, 1968, Nyíri, 1992). "The primary fact is not the I, the Ego, but the elements (sensations). The elements constitute the I. ... when I die... only an ideal mental-economical unity, not a real unity, has ceased to exist (Mach, 1897, p. 19-20)". Notice the same half tragic half ironical preoccupation with the issue of how can one assure survival of one's thoughts if one does not believe in the immortal and timeless soul as it appears in some writings of Dennett (e.g. 1990) and of course in Hume who claimed that we cease to feel and think with the death of the body.
The dropping of the centrality of the Ego also reduces our epistemological dualism and our scientific vanity. It is indeed related to the ideological monism so dear for Mach."As soon as we have perceived that the supposed unities "body" and "Ego" are only makeshifts, designed for provisional survey and for certain practical purposes, we find ourselves obliged, in many profound scientific investigations, to abandon them as insufficient and inappropriate. The antithesis of Ego and world, sensation (phenomenon) and thing, then vanishes, and we have simply to deal with the connexion of the elements " (ibid, p.11.)
On the other hand, and that is where the dissolution of the notion of the Ego or self into the elements takes up a biological flavor, he connects this Humeian reasoning with the economy principle and with evolution. The Ego or self is a practical, economic concept: we live by it, but the real analysis shows it to be only a "hypothetical entity" ("a practical unity, put together for purposes of provisional survey", Mach, 1897, p. 21) . It is a soft abstraction like the ones so dear for Dennett, the notion of Gravitational Center, or the Equator (Dennett, 1987). And its use is based on function rather than essence. Its ontological status is similar to the relationship between the intentional stance and the microanalysis of consciousness in Dennett (1991a). It is not a mere illusion, but something derived and postulated. "The Ego: it consists of memories of our experiences along with the associations provoked by them" (Mach, 1910, p. 46).
This soft concept of Ego with which we have live without taking it to be an ontological starting point has two kinds of anchorages for Mach. The first comes from our general tendency to abbreviate repeated complexes of sensations with names, that appears in our notion of physical bodies as well. "That which is perceptually represented in a single image receives a single designation, a single name" (Mach, 1897, p. 3). At the same time we should not overemphasize the unity of consciousness. "The so-called unity of consciousness is not an argument in point. ... a rich and variously interconnected content of consciousness is in no respect more difficult to understand than a rich and diversified interconnexion of the world (Mach, 1897, p. 2). Our feeling of self is only a relative, experiential unity and not a real one. Mach holds an attitude rather similar to the one taken by Dennett and Kinsbourne (1992) in their argumentation about the illusory nature of the unified Cartesian Theater.
The other anchoring point is found by Mach in the concept of body. Here Mach reiterates and modernizes an idea already apparent in the work of Condillac, and later on taken up by several theories both in comparative and in clinical psychology (Henry Head, Frederick Bartlett) that take the body schema, the representation of our body as central to the self concept. "As relatively permanent, is exhibited, further, that complex of memories, moods, and feelings, joined to a particular body (the human body), which is denominated the "I" or "Ego" (Mach, 1897. p. 3).
It is worthy to note that this centrality of the notion of body image did not disappear. It is certainly textbook material in psychology and it is seen in neuropsychological theories. Antonio Damasio (1994) in his work on the representation of emotions and their role in the shaping of our goal system claims that the emotionally laden representation of our body is the central core to our self concept. Dennett (1991a) is his view on consciousness also gives a central role to the body image in the reduction of our notion of the self.
There is one emphasis where Dennett diverges from Mach. The narrative sources of coherence did not appear yet in Mach. This is indeed a great difference and a sign of the times: for all of their similarity, the present day dissolution and reintegration view goes along with the narrative metatheory while for Mach the same function was achieved merely by opting for the body image. Dennett (1991a, pp.426-427) puts it rather clearly: "A self, according to my theory, is not any old mathematical point, but an abstraction defined by the myriads of attributions and interpretations (including self-attributions and self-interpretations) that have composed the biography of the living body whose Center of Narrative Gravity it is".
For Mach it was important to put his entire treatment of the self or Ego into a cosmic perspective. This is clearly another feature that differentiates him from present day treatments. Here he shows characteristics of his own time. He cultivates a Spencerian belief in evolution as progress that Capek (1968) clearly shows and what would hardly appear in present day evolutionary epistemologies. This was related to Mach's desire to overcome the traditional duality in epistemology and also as Blackmore (1972, pp. 286-289) observes to his interest in the Buddhist type of unity of mind and the world. Mach puts his commitment into progressive, enthusiastic phrases:"We are prepared, thus, to regard ourselves and every one of our ideas as a product and a subject of universal evolution" (Mach, 1910, p. 235). But he phrases the same thing in a more withdrawn and reluctant way: "We feel that the real pearls of life lie in the ever changing contents of consciousness, and that the person is merely an indifferent symbolic thread on which they are strung" (Mach, 1910, pp. 234-235). But both attitudes give a consolation to life. They do not merely give a cold and dispassionate scientific solution regarding the problem of the place on man in the world. They provide us a feeling of connectedness. "If the Ego is not a monad isolated from the world but a part of it, in the midst of the cosmic stream from which it has merged and into which it is ready to dissolve back again, then we shall no longer be inclined to regard the world as an unknowable something" (Mach, 1910, p. 361).
The relative stability approach taken by Mach to the issue of the Ego makes his views rather similar to the views of Dennett. Similarly the idea of an evolutionary explanation, the fact that abstract notions like that of the self have a functional story and they are evolutionary hypotheses. All of our knowledge is always tentative and hypothetical. They both claim that in the final analysis there are only elements in our mind as well as in the world, but out of those elements evolutionary working hypotheses are being formed.
Neglect and Impact of Mach There is very little presence of Mach felt on the cognitive scene. This is true regarding the philosophical interpretations of evolutionary theory as well. Even very considerate authors like Ruse (1986) when they trace the philosophical implications and usage of Darwinian ideas, entirely forget about Mach (to be sure, they also forget about Piaget or about the early work of Dennett as well). There are three aspects that make him worthy of studying and not only for the antiquarian historian of ideas. He started a remarkable tradition of treating issues of epistemology and the psychology of cognition, issues of ordinary cognition and making of science together. Lana (1976) is one of the exceptional present-day historians of psychology who noticed the importance of this fact. This continuity between epistemology and psychology is also true for almost the whole present day cognitivism: there is no dividing line between science and ordinary cognition. The unity of the two is provided by Mach in an evolutionary framework. That is true more or less for the approach taken by Dennett, too. And the interesting mediator as Dennett (1994, 1996) acknowledges it in some of his newer writings is the evolutionary epistemology tradition of Popper (1972, 1994), and his followers like Campbell (1974). Similar ideas show up even in Quine (1969, p. 90) when he allows "epistemology the resources of natural science".
One of the specific ideas central to Mach and reappearing in Dennett is the complex thought that evolution can explain behavior without making you into a "muscle twitch behaviorist". This way of thinking was taken up by other Viennese scholars. In the work of Karl Bühler (1922, 1927), a teacher of Popper, two crucial aspects appear that create a continuity from Mach to Dennett. The first is the whole notion of carefully continuing the Darwinian path and studying behavior patterns and stimulus preferences as the results of evolution. Konrad Lorenz, himself a student of Bühler, through the elaboration of comparative ethology transmitted this idea up to the present day concern with evolutionary explanations for more inner aspects of cognition. The circle that started with the evolutionary considerations of the 'subjectivist' Mach is thus closing up. As part of the extension of selectional explanations to different domains Bühler (1922) also extended the idea of Mach (1905/1976) of seeing hypothesis and trial everywhere. According to Mach, hypotheses and trials characterize not only science but of all our everyday cognition. Bühler proposed a continuity between instinct, trial and error learning and intellect. Hi student another Vienna philosopher, Karl Popper (1963, 1972, 1976, 1994) in his evolutionary epistemology extended this idea by claiming that a hypothesis - test - selection sequence is observed everywhere. When Campbell (1974) summarized the 10 different levels of use of the trial and selection notion along the lines of a Popperian evolutionary epistemology, from the trials of the paramecium to science, Mach gained a central position on his historical tableau. Bühler (1922) proposed a threefold selection field: instincts, habits, and intellect for child development. Through the mediation of Popper these correspond roughly to what Dennett (1994, 1996) calls Darwinian, Skinnerian and Popperian creatures.
By emphasizing the beginning of some of the very ideas and a whole style of philosophizing in Mach I do not intend to deny originality from present day cognitivists, or from Dennett to that effect. I only wanted to show that there is another Vienna tradition not only the one Quine (1969) refers to and that would separate natural science and philosophy by restricting the latter to the study of language. This integral tradition also comes from the neighborhood of Vienna and it continuously finds an alliance between philosophy and natural science under the metatheory of evolution. There is rather important and remarkable difference, and that is where the two Vienna traditions meet today. Mach in his evolutionary approach to cognition was missing the logical structure of cognition. What we have today in the work of Dennett and others is a meeting of the Frege-Russell-Vienna traditions with the Darwinian traditions so clearly exposed by Mach.
Acknowledgements The author was supported by a Gardner Lindzey fellowship of the Mellon Foundation while working on this paper. He would like to thank the hospitality and the intellectual climate of the Center for Advanced Studies in the Behavioral Sciences, Stanford University. Henry Aaron, Gerald Clore, Clark Glymour, and Steven Shapin at the Center, Kristóf Nyíri, Bence Nánay and Zsuzsa Káldy from Budapest shared important comments with me at different stages of my work. Extensive discussions with Alan Code, György Gergely and Miklós Gy ri on the real differences between the two authors helped me to clarify my meaning.
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