It is rare to find a great deal of agreement among philosophers and psychologists. However, concerning sense perception some basic as- sumptions have, for a ...
9
Man and World 17:3-18 (1984) Nifhoff Publishers. Printed in the Netherlands
THE DUALISTIC APPROACH TO PERCEPTION
AARON BEN-ZEEV and MICHAEL STRAUSS
University o f Haifa
It is rare to find a great deal of agreement among philosophers and psychologists. However, concerning sense perception some basic assumptions have, for a long time, been common to various opposing views. Because they were common they were hidden as well; they were not explicitly formulated or assembled under a common name. It is our aim to do just this. We term this approach "The Dualistic Approach to Perception" because it presumes a dichotomy between sensation and meaning, in which sensation in itself is meaningless. Meaning is bestowed upon sensation by the subject; sensation is prior to that bestowal. This type of dualism exists, not merely in sense reception, but also in language and art. Our discussion, however, will deal only with sense reception. Our main concern is the critical exposition of the dualistic approach and not the depiction of its historical development. The first section presents four basic assumptions of the traditional approach. The second section classifies different versions of the dualistic approach. The classification is made in light of a few basic aspects that each dualistic position has to account for. The third section indicates our criticism of this approach.
The dualistic approach to perception began to prevail in the seventeenth century, its formation into a more coherent system occurred in the eighteenth and nineteenth centuries, and signs regarding its inevitable collapse can be seen in the twentieth century. The dualistic approach has four basic assumptions:
4 (A) Sensation is meaningless; it lacks any cognitive, emotional, and evaluative content. (B) There is a constant one-to-one correlation between the (proximal) stimulus and sensation. Therefore, the agent's knowledge, memory (past experience), expectations, will, and other mental states do not influence his sensation. (C) There is a difference between sense reception and sense perception; the former (which is termed 'sensation') is meaningless and the latter (which is termed 'perception') is meaningful. (D) Meaning is added to sensation by the mind through inference, interpretation, elaboration and response. Meaning added in these manners is, afterward, assimilated into sensation in such a way that only reflective analysis can separate it again? These assumptions may be divided into two groups. The first two assumptions depict the meaningless sensory stage: the first assumption postulated its existence and the second describes its origin. The other two assumptions indicate the place of that stage in the whole perceptual system: the third assumption points out the existence of another perceptual stage and the fourth characterizes the transition between the sensory and perceptual stages. According to the first assumption, sensation is meaningless in all possible dimensions: cognitive, emotional and evaluative. What we actually see are not the meaningful everyday objects but something else: "Every one agrees that chairs and tables are perfectly good things - they are there and can be touched - but all competent to form an opinion are equally agreed that whatever we see is certainly not them.": The emphasis is on the absence of any cognitive content. Because of this absence, sensation is not regarded as knowledge, but merely as response to external stimulus. Hence, it is neither true nor false. It is a starting point which is given to the cognitive system, and is in no way a product of that system. Therefore Russell argues that "The sensations caused by external objects are events like any others, and have not the characteristics that we associate with the word 'cognition'. ''3 Since sensation lacks any cognitive content, it cannot be false; there is nothing in it that can be mistaken: "There are in fact no illusions of the senses but only mistakes in interpreting sensational data as signs of things other than themselves. ''4 This contention bestows a privileged epistemic status upon sensations: it is the infallible datum of knowledge. The absence of cognitive content also prevents sensation from being true. It is merely a response which serves as a sign. Sensation does not have any emotional and evaluative content either, being neutral in
5 light of these aspects. Thus, the happiness or fear we see on someone's face is considered to be a later subjective addition. A consistent dualist has to adopt the same attitude toward pleasure and pain. The second assumption deals with the cause o f the meaningless sensation. The general thesis is clear: the cause is physical and not mental. Every mental feature which characterizes an individual agent is excluded from these causes. In order "to arrive at what really is sensation ... we have to pare away all that is due to habit or expectation or interpretation. ''s The cause of sensation is the physical stimulus. Every external, physical stimulus has a specific sensory response (one sensation). In this view, one senses what the external stimulus dictates. The external stimulus, however, is not the ultimate cause of sensation; the latter is a certain neurological event. In order to keep the one-to-one correlation between the external stimulus and a specific sensation, one has to presume some sort of a passive physiological conduit which faithfully transmits the proporties o f the external stimulus to the mind. This presumption enables one to hold, what KShler terms, "the constancy hypothesis," i.e., "the point-to-point determination of local sensory facts by local stimuli. ''6 Hence, a sense-datum - or sensation is "the core, in a perceptionl which is solely due to the stimulus and sense-organ, not to past experience. ''7 The first two assumptions, then, describe sensation and its origin. However, this description is contrary to the c o m m o n sense which accepts the meaningful content of perception as given. Thus, we perceive that the objects in front o f us are tables and chairs, that one man pushes another (these perceptions have cognitive content which m a y be mistaken), that someone's face is happy, that a mother's attitude is that of care and concern (these have emotional content), that torture is painful and ice cream is pleasant (these have evaluative content). In order to account for this meaningful stage, the third assumption postulates the sensation-perception distinction. Sensation is the meaningless stage while perception is the meaningful one: "Sensations are 'pure' experiences in that they do not have organization, meaning, or association. Perception is conscious experience that has some degree o f organization and meaning. ''8 And Russell has the same attitude: But although sensation is a s o u r c e of knowledge, it is not itself, in any usual sense, knowledge . . . . 'Perception', as the word is used by most psychologists, is o f the nature o f knowledge, but it is so because o f the adjuncts which are added to pure sensation by experience, or possibly, by congenital dispositions. 9
Despite the fact that the distinction between the meaningless sensory stage and the meaningful perceptual stage is a basic tenet in the traditional approach, "an explicit distinction between sensation and perception has only rarely been made. ''~~ This is probably due to the difficulties of presenting a clear and consistent account of that approach. Consequently, the terms used to describe this approach are not always the same. Since our main concern here is the expositi6n of the dualistic approach and not its historical examples, we shall not dwell on that matter. The dualistic distinction between a passive stage, in which the subject receives everything from the outside and an active stage, which includes features that are due to the subject's activity, is clearly expressed in Kant's distinction between the receptivity and spontaneity of the subject; sensation stems from the former, and understanding from the latter. These capacities are very far from each other; only their union can make knowledge possible. The raw material is claimed to be passively received from the outside, while meanings are said to stem from the inside. Once the existence of two perceptual stages is postulated, a description of the transition between them is required. The transition is usually described as that in which the mind interprets meaningless raw material thereby endowing it with meaning: perception is that power which interprets the raw materials given by sensations. Perception, always aided by the other faculties, gives us our first exact knowledge .... To our mental ear sensations are all the while speaking, but their language is unintelligible until perception interprets it. 1 In the next section, we shall indicate some disagreements among the dualists regarding other features of that transition, e.g., whether it is a conscious or an unconscious inference. The dualistic approach to perception may be described in terms of the five traditional factors, assumed to be involved in the following order in the causal process of perception: (a) the stimulus' source (what is usually called the 'distal stimulus'), e.g., the table; 12 (b) the stimulus (or in its traditional term 'the proximal stimulus'), e.g., the light rays coming from the table; (c) physiological processes; (d) sensation; and (e) perception. The dualistic approach may then be formulated as follows:
(i)
The relationship between the stimulus' source and the stimulus is equivocal; to wit, the latter does not unequivocally specify the former. (ii) Sensation does not display any degree of independence from the stimulus or its inevitable physiological effect; therefore, sensation does not involve active mental contributions. (iii) Since only active mental contributions can overcome the stimulus' equivocation, sensation cannot reflect the stimulus' source. (iv) Perception is not in correspondence with the stimulus, but it is supposed to reflect the stimulus' source. (v) Hence, perception must involve active mental contributions which overcome the stimulus' equivocation. To sum up, a major feature of the dualistic approach to perception is the distinction between the meaningless sensory stage and the meaningful perceptual one. The first stage (sensation) is the effect of a physical cause; there are no active mental contributions in its creation. The second stage (perception) is the meaningful, everyday perception; mental (mainly cognitive) features are very active in its creation.
II Having presented the basic assumptions of the dualistic approach, we now turn to the classification of the different versions of that approach. The classification is made according to the two groups of assumptions of that approach: (I) assumptions concerning the meaningless sensation (assumptions A, B), and (II) assumptions in regard to the supplement which is added to sensation in order to get perception (assumptions C, D). Indeed, the postulation of the meaningless sensory stage, and hence the process of enriching it, are the unique theses of the dualistic approach. The different versions of the dualistic theories of perception may then be classified according to the following aspects: (I) The characterization of sensation. (A)The nature of the disorder (meaninglessness) that exists in sensation. (B) The degree of the disorder (meaninglessness) that exists in sensation. (C) The status of sensation. (II) The characterization of the supplement added to sensation. (A) The nature of the supplement. (B) The way the supplement is added.
(C) The origin of the supplement. Each dualistic theory should account for all of these six aspects. Let us describe these accounts in more detail.
(1.4) The nature o f the disorder (meaninglessness) that exists in sensation Meaningfulness is connected with order and relation. Something completely isolated, i.e., that has no relation whatsoever to anything else, cannot be known. Conceptual meaning, as Lewis rightly claims, is closely analogous to a point in space: "A point is nothing whatever apart from its relation to other points; its very essence is relational." Consequently, all that is intelligible (meaningful) about something "is the set of relations in which it stands . . . . What does not affect discrimination and relation has no handle by which the mind can take hold of it. ''13 All versions of the dualistic approach assume that sensation is, to a certain extent, meaningless, that is, orderless. They differ in regard to the nature (and the extent) of the disorder. Order is absent in two extreme cases in which meaningful relations cannot exist: (a) in isolated atoms which are indifferent to each other, and (b) in a chaotic, smooth, undifferentiated flux. These are the two dualistic alternatives concerning the nature of the disorder that exists in sensation. The atomistic view is the more prevalent one. Hume is a representative of that view: ... every distinct perception, which enters into the composition of the mind, is a distinct existence, and is different, and distinguishable, and separable from every other perception, either contemporary or successive . . . . the mind never perceives any real connexion among distinct existences. 14 In extreme atomistic theories, the mind is only capable of experiencing a single uniform sensation at a given time. The philosophers and psychologists (e.g., James) who speak about a stream of consciousness prefer the second alternative for describing the disorder that exists in sensation. In the first alternative, meanings are added by a process of synthesis, while in the second alternative, by analysis.
9 (IB) The degree of disorder (meaninglessness) that exists in sensation This is a more basic aspect according to which the various versions of the dualistic approach can be distinguished. Here we distinguish between extreme and moderate dualism. The extreme dualist claims that sensation is completely meaningless; it is devoid of all types of relation. A more moderate position admits the existence of some primitive meanings (or relations) in sensation. Locke's account of sensation, which is an early (and very moderate) formulation of the dualistic approach, is still quite broad (but when compared to everyday perception it is still restrictive). In addition to secondary qualities, one may find, in Locke's sensation, size, shape, and even concepts like existence, unity, power, and succession. These properties include relations; for example, shape and succession contain spatial and temporal relations. Philosophers after Locke doubted his broad depiction and diminished the content of sensation. Perceiving relations, like establishing new ones, was regarded as an activity involving forbidden active mental contributions. The diminishing process had already begun with Berkeley, but is best illustrated in Hume's work. Hume claims that the only relations "immediately present to the sense" are identity and certain "relations of time and place. "is Kant's claim that Space and Time are a priori forms of intuition whose origin is the subject's spontaneity is contrary even to the assumption that primitive temporal and spatial relations are given. Indeed, Helmholtz excludes spatial relations from pure sensation, and leaves only the temporal relations of succession and duration. The most extreme view which excludes all types of relation - and hence meaning - from sensation is rare, since it creates difficulties (to be discussed below) in describing the relation between sensation and perception. However, some examples of it can be found especially in the second half of the nineteenth century and the first half of the twentieth century. Thus Ernst Dfirr claims that every perceptual meaning stems from the subject. Sensations, Dt~rr argues, do not contain any spatial or temporal dimension; one does not see patches of colors, but the qualities of color. The sensations differ from each other only in their qualities and intensities. 16 Wundt, too, asserts that in order to arrive at the objective content of immediate experience, i.e., pure sensations, we must neglect "all the connections of these sensations with others, and also all their spatial and temporal relations. ''aT In extreme (and late) formulations of the dualistic approach, the lack of all kinds of relation results in completely meaningless sensation: "Sensations are 'pure' experiences in that they do not have organiza-
10 tion, meaning, or association. ''18 The "actual 'raw' sensation" is described as "meaningless, unidentified, uninterpreted, 'raw' experience. ''19 Hence one may contend that The first conscious effect that can be traced to a stimulus of the sense-organs is a feeling which does not possess spatial or temporal quality, that is to say, is not felt to be located or extended in space or time, or to have the definite qualities and relations usually associated with sensations? ~ The extreme dualistic stand is consistent with the basic dualistic assumptions, but the way it describes sensation is (a) quite different from what we actually encounter in everyday life, and (b) acutely susceptible to the difficulties of the dualistic approach. The exclusion of any relation - and hence meaning - from sensation is the logical outcome of the basic dualistic tenet concerning the meaninglessness of sensation. But in everyday life we never encounter such sensation, and the difficulties of such a pure mental state and o f explaining how the mind constructs a meaningful world out of it, are very severe. Therefore, the extreme (and consistent) formulations o f the dualistic approach are not common. In any case, the great advocates of that approach do not present a consistent and coherent formulation. (In our presentation we try to suggest such a formulation; it facilitates the understanding of that approach and the reasons one should reject it). Moderate dualistic formulations have the opposite problem: by sneaking into the stage of sensation some relations and primitive meanings in these formulations are not consistent with basic tenets o f the dualistic approach, but are closer to what we actually encounter in everyday life, and are less susceptible to the difficulties of the dualistic approach.
(IC) The status of sensation The two major alternatives of the dualistic approach in this regard are (a) an actual mental stage, and (b) an abstract (theoretical) concept. Despite the absence o f active mental contributions o f the mind in sensations, sensations are usually considered to be constructed out of the same "metaphysical m a t t e r " (to use an expression of Leibniz') that constitutes the mind. Sensation is a mental state, but it lacks the cognitive, emotional and evaluative features which are so typical of mental phenomena. The causes which determine the features o f sensa-
11 tion are physical, but its matter is mental. Sensation is an initial, primi L tire mental stage. As previously mentioned, moderate (and early) formulations of the dualistic approach depict sensation in quite a broad way which is not too remote f r o m the actual initial perceptual stage. Therefore the dualists could claim (though not without difficulty) that sensation is an actual (empirical) perceptual stage. Once all kinds of relations - including spatial and temporal - are excluded from sensation, it is hard to characterize sensation as an actual perceptual stage since all of our perceptual stages are full of such relations. This is the background for the rise of the second alternative concerning the status of sensation, i.e., the view which conceives sensation as an abstract (or theoretical) concept. This view, which is related to the extreme formulations of the dualistic approach, is very popular in the early twentieth century's philosophical and psychological discussions regarding the notions of "sense-data" and "the given." The advocates of this view are convinced that we cannot find an actual, empirical stage which fulfills the purity requirement of sensation, and in order to keep that requirement, they posit pure sensation as an abstract concept. Thus Lewis claims that We do not see patches of color, but trees and houses; we hear, not indescribable sound, but voices and violins .... T h e given, as here conceived, is certainly an abstraction. Unless there be such a thing as pure esthesis (and I should join with the critic in doubting this), the given never exists in isolation in any experience or state of consciousness? 1 Russell also occasionally represents sensation as "a theoretical core in the total occurrence) ~
(IIA) The nature of the supplement In this issue the dispute is whether the richness which differentiates perception from sensation consists of intellectual or sensory qualities. The mainstream is committed to the former alternative. According to that view, when I meet Tom who has lately gained a lot of weight, I do not see that he has gained weight, rather I see that his size has increased. I cannot see weight but I can think about weight. When I perceive that Tom has gained weight, I refer to a sensory content in addition to intellectual quality: "Sensations are simple, elementary; percep-
12 tions are complex and comprise a number of related sensory, imaginal, and thought factors. ''2a The other alternative can be described as a sensualistic reductionism. Since this alternative asserts that all kinds of meaning are sensory ones, it must claim that the supplement added to Sensation consists of sensory content as well. The meaning of a certain sensation is nothing more than another sensation which is combined with it by association. Hume, for instance, holds this view. (An opposite kind of reduction, which does not belong to the dualistic approach, conceives the sensory content itself as a confused intellectual concept. Here sensation is reduced to meaning. This is Leibniz' view.) The two alternatives are not without their problems. A crucial dil e m m a in each is whether the assumed supplement modifies (and is not merely added to) the sensory core. For instance, the dilemma is whether the sensory core of a green patch can be changed - due to active mental contributions - into, not merely the perception of a book (which one may claim is an intellectual quality), but also into the perception of a red patch (which is clearly a sensory quality). The empirical evidence clearly supports the claim that the assumed supplement indeed modifies the sensory core, :4 and hence may consist of sensory qualities, as the second alternative suggests. But if, indeed, the supplement added to the sensory content consists o f sensory qt~alities w h y should one assume in the first place the dualistic dichotomy between the two?
(IIB) The way the supplement is added The dualistic approach assumes that the mind adds meaning to meaningless sensation. There is a dispute concerning the way it is done: whether it is a conscious or unconscious cognitive process. The early dualists (viz. Descartes and the early empiricists), who identified the mental with the conscious, conceived o f it as a conscious process. The difficulty of this view is that we are not aware of that transition. This unawareness is explained by claiming that "in these matters custom makes us reason and judge so quickly, or rather we recall the judgements previously made about similar things. ''2s The second alternative, whose main proponent is Helmholtz, gives up this problematic explanation (which actually admits that this process is unconscious) and assumes that the transition is an unconscious inference. The above two alternatives refer to the formulation in which sensa-
13 tion is an actual mental stage; if sensation is regarded as an abstract concept, these alternatives are not relevant. In the latter case, sensation and perception exist simultaneously and there is not an actual, temporal process of transition between them. We can distinguish between the two stages only through an abstract analysis. The same position is found in those views (e.g., Kant's and Dt~rr's) in which the transition between the two stages is that of a transcendental employment of subjective faculties.
(IIC) The origin of the supplement added to sensation According to the dualistic approach, sensation is meaningless and all meaning is added to it; hence, the question of the origin of that supplement arises. The two main alternatives here are empiricism and nativism. Empiricism claims that the added meanings are acquired through experience, while nativism conceives of that origin as an innate system into which the meaningless sensations are inserted. We may note that the nativism-empiricism dispute is quite relevant to a dualistic approach which assumes a two-stage theory of perception: (a) a meaningless (pure, neutral) starting-point, and (b) an addition of meanings to the first stage. In that approach the nativism-empiricism dispute regarding the origin of the added meaning is very significant. However, in an approach which denies a meaningless starting-point the issue cannot be answered in simplistic "yes" or " n o " answers (both of which lead to implausible positions), but one must analyse the different perceptual factors in order to adequately indicate the several variables. This section has described the different versions of the dualistic approach to perception. They were classified in light of six basic features, Three features refer to the characterization of the meaningless sensation and the other three refer to the characterization of the meaningful supplement added to sensation. The typical view regarding the first issue is that which takes an atomistic stand concerning the nature of disorder that exists in sensation, a moderate attitude toward the degree of disorder found in sensation, and a position in which sensation is an actual mental stage. The typical view concerning the second issue is the position in which the supplement is an intellectual quality, a stance which describes the way the supplement is added as an unconscious cognitive process, and the empiricist viewpoint
14 in regard to the origin of the supplement. Helmholtz seems to hold all of these positions; as such, he is a very typical representative of the dualistic approach to perception. That approach is clearly expressed, for example, in his claim that "The main thesis of the empirical standpoint is that sense impressions are signs for our consciousness, the interpretation of which is left to our intellect. ''26
III This section presents some of the arguments against the dualistic approach to perception. The many versions of this approach make it impossible for us to criticise all of them here separately; instead, we shall concentrate on the more typical dualistic position. In contrast to that position we argue that (a) there is not a pure (meaningless) sensory stage, and (b) the transition from a meaningless sensory stage to a meaningful perceptual stage is impossible. The dualistic approach assumes some sort of a neutral reception room in the mind that is not influenced by other mental components. The events in that room consist of mental stuff, but their creation merely involves mental response which is constant in relation to a given stimulus. The changes which the mental system undergoes do not influence the nature of that mental response. All developing and changing mental factors (such as one's knowledge, memory, will, emotion, expectations) which in fact constitute one's mind, are prevented from influencing the stuff in that reception room. Since meanings, according to that approach, stem exactly from those mental factors, their absence in the reception room implies that the stuff in that room is meaningless. Let us now present our arguments against that contention. A major argument against the postulation of a pure mental state is that there cannot be a state in a system that is not influenced by the nature of that system; there cannot be a mental state which is not influenced somehow by the typical features of one's mind. Sensation, in the dualistic approach, is characterized as a mental response, but the nature of the responding system (which consists of one's knowledge, memory, will, emotion, expectations, etc.) is assumed not to be a factor in determining that response. This assumption, when compared with other scientific assumptions, is striking in its oddity. With regard to all other things, we claim that their present condition is influenced by their past condition; only with regard to sensation is this claim, according to the dualistic approach, not valid. This mental stage is
15 claimed to be independent of past experience. Contrary to that contention we argue that the mental state, by definition, cannot be purified of contributions of the mental system. This is a theoretical argument against the possibility of any "pure" state. Ou r objection to the existence of pure sensation is not merely theoretical but empirical as well. There is no empirical evidence for the existence of a pure (meaningless) sensory stage. Every sensory quality which has been put forward as included in that stage has been found to be "contaminated" with meaning. One cannot find a reception room in the mental system in which qualities are passively registered and await their treatment the moment a quality becomes mental, it is already loaded with contributions of the mental system. As Sherrington remarks, "mind rarely, probably never, perceives any object with absolute indifference." Pure sensation should be, according to the dualistic approach, devoid of any kind of relation (and hence meaning). It should be something like an isolated sensory atom or a chaotic flux. However, even in these two cases it is hard to see how sensation can be without any kind of relation. A chaotic flux, no doubt, contains certain spatial and temporal relations since it has both temporal and spatial extension. Also, a visual atom must have spatial extension; otherwise, how could we see it? But such extension implies the existence of a certain shape and hence spatial relation. Furthermore, a shape that has parts is contrary to the very notion of a sensory atom. Similarly, an auditory atom must include temporal relations; otherwise we could not hear melodies and other phenomena involving change over time. The two suggestions for relationless (orderless) situations are then not adequate, and we do not see other adequate suggestions. Let us turn now to the second major aspect of our criticism: the transition from a meaningless sensory stage to a meaningful perceptual one. We claim that such transition is impossible. The fundamental difficulty is how can the mind create a meaningful world out of completely meaningless materials? In the same way that one cannot construct buildings out of mere ideas, one cannot construct a meaningful world out of meaningless materials. In both cases, the construction process must use relevant raw materials. Take, for example, the ab~ sence of spatial and temporal relations. How can the mind construct such relations from stuff which is completely devoid of them? Even if a moderate dualist assumes that only temporal relations are given in sensation, we still have the problem of constructing the spatial relations. A similar difficulty exists when only spatial relations are given. 2T
16 The above transition is even more problematic if we realize that by this transition the mind does not merely have to construct a meaningful perceptual world, but this world has to reflect the stimuli's sources. The sensory content, y o u may recall, is merely a sign of the stimulus' source. Now, if this sign is presented without any code for finding out what the sign stands for, the process o f reconstruction is impossible; but if the sign is presented with its code, it is already meaningful. A dualistic counter-argument to our criticism may run as follows: " Y o u argue that the dualists assume a meaningless sensation while y o u claim it has certain meanings. However, y o u admit that actually the dualist presumes the existence of some primitive meanings in sensation (and by this they are not so consistent). So actually there is not much of a difference between the two positions." In reply to such an argument we must note that the dispute concerning the extent to which sensation is meaningful is merely the upshot of a more basic dispute: Is the sensation-meaning relation internal or external? We hold the former view while the dualists hold the latter. They assume an opposite relation between sensation and meaning: the more sensory a sensation is, the less meaningful it is. It is exactly this relation to which we are opposed. In this paper we have tried to combine, into what we term "The Dualistic Approach to Perception," various theories and contentions. By doing so, we present an approach which is more consistent than it has actually been. However, we do believe that the basic assumptions of this approach can be found in most perceptual theories since the seventeenth century. It is high time t h a t an alternative approach be developed .28
NOTES 1. A. Gurwitsch gives the same name and a similar general picture of the above approach: "This general dualistic conception appears in the very distinction between 'sensation' and 'perception'.... The important point is that, according to all traditional theories, percepts are asserted to grow out of mere sense-data owing to supervenient factors (of whatever kind and description) by means of which sensations are interpreted and meaning is bestowed upon them" (The Field of Consciousness [Pittburgh: Duquesne University Press, 1964], p. 88). 2. C.K. Ogden and I.A. Richards, The Meaning of Meaning (London: Routledge & Kegan Paul, 1949), p. 77. One may wonder who those are "all competent to form an opinion"; apparently the authors include themselves among them. 3. B. Russell, An lnquiry into Meaning and Truth, 1940 (London: Unwin, 1980), p. 119. Since the dualistic approach is clearly expressed in Russell's writings, we shall refer to them quite often.
17 4. B. Russell, Human Knowledge, (New York: Simon & Schuster, 1948), p. 167. 5. B. Russell, The Analysis of Mind (London: George Alien & Unwin, 1921), p. 140. The same stand is found in F.I. Dretske, Seen and Knowing (Chicago: University of Chicago Press, 1969), p. 75. 6. W. K5hler, Gestalt Psychology, 1929 (New York: Mentor, 1975), pp. 66-70. 7. B. Russell, Philosophy (New York: Norton, 1927), p. 204. 8. L.F. Shaffer, B. yon H. Gillmer, and M. Schoen, Psychology (New York: Harper, 1940), p. 202. 9. B. Russell, Human Knowledge, p. 442. 10. D.W. Hamlyn, Sensation and Perception (London: Routledge & Kegan Paul, 1961), p. 186. 11. R.P. Halleck, Psychology and Psychic Culture (New York: American Book, 1895), pp. 66-67. 12. As J.J. Gibson rightly remarks, objects such as tables and houses are "sources of a stimulus array but they are not stimuli at all. They are not even 'distant' stimuli, to be precise" ("The Legacies of Koffka's Principles," Journal of the History of the Behavioral Sciences, 7[19711, p. 5). 13. C.I. Lewis, Mindand the World Order, 1929 (New York: Dover, 1956), pp. 82, 128. 14. D. I-Iume, A Treatise of Human Nature, 1739-40 (Oxford: Clarendon, 1978) pp. 259,636. 15. G. Berkeley, A Treatise Concerning the Principle of Human Knowledge (1910), sec. 142; Hume, A Treatise of Human Nature, p. 73. 16. E. Diirr, Erkenntnistheorie (Leipzig: Quelle & Meyer, 1910). 17. W. Wundt, Outlines of Psychology (Leipzig: Engelmann, 1907), p. 32. 18. L.F. Schaffer, B. yon H. GiUmer, and M. Schoen, Psychology (New York: Harper, 1940), p. 202. 19. R.H. Wheeler and T.D. Cutsforth, "Synaesthesia, a Form of Perception," PsychologicalReview, 29 (1922), 212-220, p. 216. 20. F.R. Bichowsky, "The Mechanism of Consciousness: Pre-Sensation," American Journal of Psychology, 36 (1925) 588-596, p. 539. 21. Lewis, Mind and the World Order, p. 54; see also Wundt, Outlines of Psychology, p. 40. 22. B. Russell, My Philosophical Development (London: Unwin, 1959), p. 106. See also R. Firth, "Sense.-Data and the Percept Theory," Mind, 38 (1949), 434-65 ;pp. 4 4 4 - 6 . 23. D. Mojor~ The Elements of Psychology (Columbus: Adams, 1914), p. 118. 24. See, e.g., C.K. Adams, "An Experimental Study of Memory Color and Related Phenomena," The American Journal of Psychology, 34 (1923), 359-407. Not surprisingly, Adams' excellent research did not receive proper attention. 25. R. Descartes, Obfections and Replies, in The Philosophical Works of Descartes, H E.D. I-Ialdane and G.R.T. Ross (eds.), (Cambridge: Cambridge University Press, 1955), p. 252. 26. H. yon I-Ielmholtz, Treatise on Physiological Optics, III, 1866 (New York: The Optical Society of America, 1925), sec. 33. 27. As I-Iamlyn rightly remarks: "If sensations differ qualitatively only, no amount of association can provide a knowledge of either the extension or the localization of the objects which produce them. This result might be achieved if the sensations of the associated movements themselves provided the knowledge;
18 but if these sensations in turn constitute merely a series of sensations in time, there is no hope" (Sensation and Perception, p. 155). 28. Further discussions concerning issues related to the essay's topic and the alternatives to the dualistic approach can be found in M. Strauss, Empfindung, Intention und Zeichen: Typologie des Sinntragens (Freiburg: Alber, in press); A. Ben-Zeev, "Toward a Different Approach to Perception," International Philosophical Quarterly, 23 (1983): 4 5 - 6 4 ; A. Ben-Zeev, "The Kantian Revolution in Perception," Journal for the Theory of Social Behaviour (in press); A. Ben-Zeev, "Psychological Categorization," Methodology and Science 16 (1983), 243-256; A. Ben'Zeev, "The Percivity Assumption of the Sensation-Perception Distinction," The British Journal for the Philosophy of Science (in press).
