A Historical Introduction to the Philosophy of Mind

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1 A Histoical ntoduction to the Philosophy of Mind Readings With Commentay NOTCE This mateial may be potected by opyight Jaw (llue 17 U.S. Code.) Pete A. Moton boadview pess

2 164 A Histoical ntoduction to the Philosophy uf Mind Cal G. Hempel 1 'he Logical Analysis of Psychology" Autho's pefatoy note, The oiginal Fench vesion of this aticle was published in By the time it appeaed in English, had abandoned the naow tanslationist fom of physicalism hee set foth fo a moe libeal eductionist one, efeed to in note 1, which pesents psychological popeties and states as patially chaacteized, but not defined, by bundles of behavioal dispositions. Since then, have come to think that this conception equies still futhe boadening, and that the intoduction and application of psychological tems and hypotheses is logically and methodologically analogous to the intoduction and application of the tems and hypotheses of a physical theoy.* The consideations that pompted those changes also led me long ago to abandon as untenable the veificationist constual of the "empiical meaning" of a sentence-a constual which plays such a cental tole in the aguments set foth in this aticle. Since the aticle is so fa fom epesenting my pesent views, was disinclined to consent to yet anothe epublication, but yielded to An ealie vesion of this pape appeaed in Ausonio Maas, ed., ntentionality, Mind. and language (Ubana: Univesity of llinois Pess, 1972), pp , and in Hebet Feigl and Wilfid Sellas, eds., Readings in Philosophical Analysis (New Yok: Appleton-Centuy-Cofts, 1949), pp , tanslated fom the Fench by W. Sellas. Repinted, with evisions by the autho, with pemission of the autho, Hebet Feigl, Wilfid Sellas, and the editos of &vut de Synthtst. *My easons ae suggested in some of my moe ecent aticles, among them "Logical Positivism and the Social Sciences," in P. Achinstein D. Block's plea that it offes a concise account of an ealy vesion of logical behavioism and would thus be a useful contibution to this anthology. n an effot to enhance the closeness of tanslation and the simplicity of fomulation, have made a numbe of small changes in the text of the oiginal English vesion; none of these affects the substance of the aticle. One of the most impotant and most discussed poblems of contempoay philosophy is that of detemining how psychology should be chaacteized in the theoy of science. This poblem, which eaches beyond the limits of epistemological analysis and has engendeed heated contovesy in metaphysics itself, is bought to a focus by the familia altenative, "s psychology a natual science, o is it one of the sciences of mind and cultue ( Geisteswissmschaftm)?" The pesent aticle attempts to sketch the geneal lines of a new analysis of psychology, one and S.F. Bake, eds., The Legacy of Legal Positivism (Baltimoe: Johns Hopkins Univesity Pess, 1969); "Reduction: Ontological and Lingustic Facets," in S. Mogenbesse, P. Suppes, and M. White, eds., Philosophy. Scien«, and Mtthod: Essays in Hono of Enest Nagel (New Yok: St. Matin's Pess, 1969); "Dispositional Explanation and the Coveing Law Model: Response to Laid Addis," in A. C. Michalos and R.S. Cohen, eds., PSA 1974: Poceedingofthe 1974 Bimnia/MeetingofthePhilosophy ofscimu Association (Dodecht: Reidel, 1976), pp ' which makes use of igoous logical tools, and which has made possible decisive advances towad the solution of the above poblem. 1 This analysis was caied ou by the "Vienna Cicle" (Wiene Keis), the membes of which (M. Schlick, R. Canap, P. Fank, 0. Neuath, F. Waismann, H. Feigl, etc.) have, duing the past ten yeas, developed an extemely fuitful method fu the epistemological examination and citique of the vaious sciences, based in pat on the wok of L. Wittgenstein. 2 We shall limit ouselves essentially to the examination of psychology as caied out by Canap and Neuath. The method chaacteistic of the studies of the Vienna Cicle can be biefly defined as a logical ttnaf)>sis of the language of siimct. This method became possible only with the development of a subtle logical appaatus which makes usc, in paticula, of all the fomal pocedues of moden symbolic logic.3 Howeve, in the following account, which does not petend o give mqe than a boad oientation, we shall limit ouselves to setting out the geneal pinciples of this new method, without making use of stictly fomal pocedues. Pehaps the best way to chaacteize the position of the Vienna Cicle as it elates to psychology, is to say that it is the exact antithesis of the eutent epistemological thesis that thee is a fundamental diffeence between expeimental psychology, a natual science, and intospective psychology; and in geneal, beween the natual sciences on the one hand, and the sciences of mind and cultue on the othe.4 The common content of the widely diffeent fomulations used to expess this contention, which we eject, can be set down as follows. Apat fom cetain aspects clealy elated to physiology, psychology is adically diffeent, both in subject matte and in method, fom physics in the boad sense of the tem. n paticula, it is impossible to deal adequately with the subject Cat G. Hempel 165 mate of psychology by means of physical methods. The subject matte of physics includes such concepts as mass, wave length, tempeatue, field intensity, etc. n dealing with these, physics employs its distinctive method which makes a co.mbined use of desciption and causal explanation. Psychology, on the othe hand, has fu its subject matte notions which ae, in a boad sense, mental. They ae toto gmee diffeent fom the concepts of physics, and the appopiate method fu dealing with them scientifically is that of empathetic insight, called "intospection," a method which is peculia to psychology. One of the pincipal diffeences between the two kinds of subject matte is geneally believed to consist in the fact that the objects investigated by psychology-in contadistinction to those of physics-ae specifically endowed with meaning. ndeed, seveal poponents of this idea state that the distinctive method of psychology consists in "undestanding the sense of meaningful stuctues" (sinnvolk Gebilde vestehmd zu eifassm). Take, fo example, the case of a man who speaks. Within the famewok of physics, this pocess is consideed to be completely explained once the movements which make up the utteance have been taced to thei causes, that is to say, to cetain physiological pocesses in the oganism, and, in paticula, in the cental nevous system. But, it is said, this does not even boach the psychological poblem. The latte begins with undestanding the sense of what was said, and poceeds to integate it into a wide context of meaning. t is usually this latte idea which seves as a pinciple fo the fundamental dichotomy that is intoduced into the classification of the sciences. Thee is taken to be an absolutely impassable gulf between the natual sciences which have a subject matte devoid of meaning and the sciences of mind and cultue, which have an intinsically meaningful subject matte, the appopiate methodological instument fo the scientific study of which is "compehension of meaning."

3 < both l66 A Histoical ntoduction to the Philosophy of Mind CHAf'TfR 7 Cal G. Hempel 167 The position in the theoy of science which we have just sketched has been attacked fom seveal diffeent points ofview. 5 As fa as psychology is concened, one of the pincipal countetheses is that fomulated by behavioism, a theoy bon in Ameica shotly befoe the wa. (n Russia, Pavlov has developed simila ideas.) ts pincipal methodological postulate is that a scientific psychology should limit itself to the study of the bodily behavio with which man and the animals espond to changes in thei physical envionment, and should poscibe as nonscientific any desciptive o explanatoy step which makes use of tems fom inttospecive o "undestanding~ psychology, such as 'feeling', 'lived expeience', 'idea', Will', 'intention', 'goal', 'disposition', 'epession'. 6 We find in behavioism, consequendy, an attempt to constuct a scientific psychology which would show by its success that even in psychology we have to do with puely physical pocesses, and that theefoe thee can be no impassable baie between psychology and physics. Howeve, this manne of undetaking the citique of a scientific thesis is not completely satisfiu:toy. t seems, indeed, that the soundness of the behavioistic thesis expounded above depends on the possibility of ful1illing the pogam of behavioistic psychology. But one cannot expect the question as to the scientific status of psychology to be setded by empiical eseach in psychology itsel To achieve this is athe an undetaking in epistemology. We tum, theefoe, to the consideations advanced by membes of the Vienna Cicle concening this poblem. V Befoe addessing the question whethe the subject mattes of physics and psychology ae essentially the same o diffeent in natue, it is necessay fist to claify the vey concept of the subject matte of a science. The theoetical content of a science is to be found in statements. t is necessay, theefoe, to detemine whethe thee is a fundamental diffeence between the statements of psychology and those of physics. Let us theefoe ask what it is that detemines the content--<>ne can equally well say the "meaning"--<>f a statement. When, fo example, do we know the meaning of the following statement: "Today at one o'clock, the tempeatue of such and such a place in the physics laboatoy was 23.4 centigade"? Oealy when, and only when, we know unde what conditions we would call the statement tue, and unde what cicumstances we would call it false. Needless to say, it is not necessay to know whethe o not the statement is tue.) Thus, we undestand the meaning of the above statement since we know that it is tue when a tube of a cettain kind filled with mecuy (in shott, a themomete with a centigade scale), placed at the indicated time at the location in question, exhibits a coincidence between the level of the mecuy and the mak of the scale numbeed t is also tue if in the same cicumstances one can obseve cetain coincidences on anothe instument called an "alcohol themomete~; and, again, if a galvanomete connected with a themopile shows a cettain deviation when the themopile is placed thee at the indicated time. Futhe, thee is a long seies of othe possibilities which make the statement ue, each of which is descibed by a "physical test sentence," as we will call it. The statement itself clealy afftms nothing othe than this: all these physical test sentences obtain. (Howeve, one veifies only some of these physical est sentences, and then "concludes by induction" that the othes obtain as well.) The staement, theefoe, is nothing but an abbeviated fomulation of all those test sentences. Befoe continuing the discussion, let us sum up this esult as follows: 1. A statement that specifies the tempeatue at a selected point in space-time can be "etanslated" without change of meaning into anothe statement-doubtless longe-in which the wod "tempeatue" no longe appeas. That tem functions solely as an abbeviation, making pnssible the concise and complete desciption of a state of affais the expession of which would othewise be vey complicated. 2. The example equally shows that two statements which diffi in fomulation can nevetheless have the same meaning. A tivial example of a statement having the same meaning as the above would be: "Today at one o'clock, at such and such a location in the laboatoy, the tempeatue was R.eaumu." As a matte of fact, the peceding consideations show--and let us set it down as anothe esult-that the meaning of a fllfement is established by the ctmdititms of its veification. n paticula, two diffeently fomulated statements have the same meaning o the same effective content when, and only when, they ae tue o both false in the same conditions. Futhemoe, a statement fo which one can indicate absolutely no conditions which would veify it, which is in pinciple incapable of confontation with test conditions, is wholly devoid of content and without meaning. n such a case we have to do, not with a statement popely speaking, but with a "pseudo-statement," that is to say, a sequence of wods coecly constucted fom the point of view of gamma, but without content? n view of these consideations, ou poblem educes to one concening the diffeence beween the cicumstances which veify psychological statements and those which veify the statements of physics. Let us theefoe examine a statement which involves a psychological concept, fo example: "Paul has a toothache." What is the specific content of this statement, that is to say, what ae the cicumstances in which it would be veified? t will be sufficient to indicate some test sentences which descibe these cicumstances. a. Paul weeps and makes gestues of such and such kinds. b. At the question "What is the matte?," Paul uttes the wods " have a toothache." c. Oose examination eveals a decayed tooth with exposed pulp. d. Paul's blood pessue, digestive pocesses, the speed of his eactions, show such and such changes. e. Such and such pocesses occu in Paul's cental nevous system. This list could be expanded consideably, but it is aleady sufficient to bing out the fundamental and essential point, namely, that all the cicumstances which veify this psychological statement ae expessed by physical test sentences. [This is ttue even of test condition b, which meely expesses the fact that in specified physical cicumstances (the popagation of vibations poduced in the ai by the enunciation of the wods, "What is the matte?") thee occus in the body of the subject a cetain physical pocess (speech behavio of such and such a kind).] The statement in question, which is about someone's "pain," is theefoe, just like that concening the tempeatue, simply an abbeviated expession of the fact that all its test sentences ae veified. 8 (Hee, too, one veifies only some of the test sentences and then infes by way of induction that the othes obtain as well.) t can be etanslated without loss of content into a statement which no longe contains the tem "pain,» but only physical concepts. Ou analysis has consequently established that a cettain statement belonging to psychology has the same content as a staement belonging to physics; a esult which is in diect conttadiccion to the thesis that thee is an impassable gulf between the statements of psychology and those of physics. The above easoning can be applied to any psychological statement, even to those which concen, as is said, "deepe psychological stata" than that of ou example. Thus, the assetion that M. Jones suffes fom intense infeioity

4 168 A Histoical ntoduction to the Philosophy of Mind feelings of such and such kinds can be confimed o falsified only by obseving M. Jones' behavio in vaious cicumstances. To this behavio belong all the bodily pocesses of M. Jones, and, in paticula, his gestues, the flushing and paling of his skin, his utteances, his blood pessue, the events that occu in his cental nevous system, etc. n pactice, when one wishes to test statements concening what ate called the deepe layes of the psyche, one limits oneself to the obsevation of extenal bodily behavio, and, paticulaly, to speech movements evoked by cetain physical stimuli (the asking of questions). But it is well known that expeimental psychology has also developed techniques fo making use of the subde bodily staes efeed to above in ode to confim the psychological discoveies made by cude methods. The statement concening the infeioity feelings of M. Jones-whethe tue o false-means only this: such and such happenings take place in M. Jones' body in such and such cicumstances. We shall call a statement which can be tanslated without change of meaning into the language of physics, a ~physicalistic statement," ' wheeas we shall eseve the expession "statement of physics" to those which ate aleady fomulated in the teminology of physical science. (Since evey statement is in espect of content equivalent to itself, evey statement of physics is also a physicalistic statement.) The esult of the peceding consideations can now be summed up as follows: AO psychological statements which ae meaningfo4 that is to sa)l which ae in pinciple veifiable, ae tanslatabk into statements which do not involve psychological concepts, but only the concepts of physics. The statements of psychology ae consequently physicalistic statemmts. Psychology is an integal pat of physics. f a distinction is dawn between psychology and the othe aeas of physics, it is only fom the point of view of the pactical aspects of teseach and the diection of inteest, athe than a matte of pinciple. This logical analysis, the esult of which shows a cetain affinity with the fundamenal ideas of behavioism, constitutes the physicalistic conception of psychology. v t is customay to aise the following fundanenal objection against the above conception. The physical test sentences of which you speak ae absolutely incapable of fomulating the intinsic natue of a mental pocess: they meely descibe the physical symptoms fom which one infes, by pu.ely psychological methods-notably that of undestanding-the pesence of a cetain mental pocess. But it is not difficult to see that the use of the method of undestanding o of othe psychological pocedues is bound up with the existence of cetain obsevable physical data concening the subject undegoing examination. Thee is no psychological undestanding that is not tied up physically in one way o anothe with the peson to be undestood. Let us add that, fo example, in the case of the statement about the infeioity complex, even the "intospective" psychologist, the psychologist who "undestands," can confim his conjectue only if the body of M. Jones, when placed in cetain cicumstances (most fequently, subjected to questioning), eacts in a specified manne (usually, by giving cetain answes). Consequently, even if the statement in question had to be aived at, discoveed, by "empathetic undestanding, the only infomation it gives us is nothing moe no less than the following: unde cetain cicumstances, cetain specific events take place in the body of M. Jones. t is this which constitutes the meaning of the psychological statement. The futhe objection will pehaps be aised that men can feign. Thus, though a ciminal at the ba may show physical symptoms of mental disode, one would nevetheless be justified in wondeing whethe his mental confusion was l i "eal" o only simulated. One mnst note that in the case of the simulato, only some of the conditions ae fulfilled which veify the statement "This man is mentally unbalanced," those, namely, which ae most accessible to diect obsevation. A moe penetating examination-which should in pinciple take into account events occuing in the cental nevous system--would give a decisive answe; and this answe would in tun clealy est on a physicalistic basis. f, at this point, one wished to push the objection to the point of admitting that a man could show aa the 'Symptoms» of a mental disease without being "eally" ill, we eply that it would be absud to chaacteize such a man as "eally nomal"; fo it is obvious that by the vety natue of the hypothesis we should possess no citeion in tems of which to distinguish this man fom anothe who, while exhibiting the same bodily behavio down to the last detail, would "in addition" he "eally ill." (To put the point moe pecisely, one can say that this hypothesis contains a logical contadiction, since it amounts to saying, "t is possible that a statement should be false even when the necessay and sufficient conditions of its tuth ae fulfilled.") Once again we see clealy that the meaning of a psychological statement consists solely in the function of abbeviating the desciption of cetain modes of physical esponse chaacteistic of the bodies of men o animals. An analogy suggested by 0. Neuath may be of futhe assistance in claifying the lo cal function of psychological statements. 9 he comp 1cated statements that would descibe the movements of the hands of a watch in elation to one anothe, and elatively to the stas, ae odinaily summed up in an assetion of the following fom: "This watch uns well (tuns badly, etc.)." The tem "uns" is intoduced hee as an auxiliay defined expession which maltes it possible to fomulate biefly a elatively complicated system of statements. t would thus be absud to say, fo example, that the movement of the Cat G. Hempel 169 hands is only a ~physical symptom" which eveals the pesence of a unning which is intinsically incapable of being gasped by physical means, o to ask, if the watch should stop, what has become of the unning of the watch. -.,..,....., t is in exactly the same way that abbeviating symbols ae intoduced into the language of physics, the concept of tempeatue discussed above being an example. The system of physical test sentences exhausts the meaning of the statement concening the tempeatue at a place, and one should not say that these sentences meely have to do with "symptoms" of the existence of a cetain tempeatue. Ou agument has shown that it is necessay to attibute to the chaacteistic concepts of psychology the same logical function as that pefomed by the concepts of"unning" and of "tempeatue." They do nothing moe than make possible the succinct fomulation of popositions concening the states o pocesses of animal o human bodies. The intoduction of new psychological concepts can contibute geatly to the pogess of scientific knowledge. But it is accompanied by a dange, that, namely, of making an excessive and, consequendy, impope use of new concepts, which may esult in questions and answes devoid of sense. This is fequently the case in metaphysics, notably with espect to the notions which we fomulated in section. Tems which ae abbeviating symbols ae imagined to designate a special class of "psychological objects," and thus one is led to ask questions about the "essence" of these objects, and how they diffe fom "physical objects." The timewon poblem concening the elation between mental and physical events is also based on this confusion concening the logical function of psychological. concepts. Ou agument, theefoe, enables us to see that the psycho-physical poblem is a pseudo-poblem, the fomulation of which is based on an inadmissible use of scientific concepts; it is of the same logical natuse as the question, suggested by the example

5 170 A Histoical ntoduction to the Philosophy of Mind Cal G. Hempel 171 above, concening the elation of the unning of the watch to the movement of the hands. 10 V n ode to bing out the exact status of the fundamental idea of the physicalistic conception of psychology (o logical behavioism), we shall conttast it with cetain theses of psychological behavioism and of classical mateialism, which give the appeaance of being closely elated to it Logical behavioism claims neithe that minds, feelings, infeioity complexes, voluntaty actions, etc., do not exist, no that thei exist ence is in the least doubtful. t insists that the vey question as to whethe these psychological constucts eally exist is aleady a pseudopoblem, since these notions in thei "legitimate use" appea only as abbeviations in physicalistic statements. Above all, one should not intepet the position sketched in this pape as amount ing to the view that we can know only the "physical side" of psychological pocesses, and that the question whethe thee ae mental phenomena behind the physical pocesses falls beyond the scope of science and must be left eithe to faith o to the conviction of each in dividual. On the contay, the logical analyses oiginating in the Vienna Cicle, one of whose consequences is the physicalistic conception of psychology, teach us that evey meaningful question is, in pinciple, capable of a scientific answe. Futhemoe, these analyses show that what, in the case of the mind-body poblem, is consideed as an object of belief, is absolutely incapable of being expessed by a factual poposition. n othe wods, thee can be no question hee of an "aticle of faith." Nothing can be an objec of faith which cannot, in pinciple, be an objec of knowledge. 2. The thesis hee developed, though daed in cetain ways to the fundamental idea of behavioism, does not demand, as does the latte, that psychological eseach estict itself methodologically to the study of the esponses oganisms make to cetain stimuli. t by no means offes a theoy belonging to the domain of psychology, but athe a logical theoy about the. statements of scientific psychology. ts position is that the latte ae without exception physicalistic statements, by whateve means they may have been obtained. Consequendy, it seeks to show that if in psychology only physicalistic statements ae made, this is not a limitation because it is logically impossibk to do othewise. 3. n ode fo logical behavioism to be valid, it is not necessay that we be able to descibe the physical state of a human body which is efeed to by a cetain psychological statement-fo example, one dealing with someone's feeling of pain-down to the most minute details of the phenomena of the cental nevous system. No moe does it pesuppose a knowledge of all the physical laws govening human o animal bodily pocesses; no a fotioi is the existence of igoously detcminisic laws elating to these pocesses a necessay condition of the tuth of the behavioistic thesis. At no point does the above agument est on such a concete pesupposition. V n concluding, should like to indicate biefly the claification bought to the poblem of the division of the sciences into otally diffeent aeas, by the method of the logical analysis of scientific staements, applied above to the special case of the place of psychology among the sciences. The consideations we have advanced can be extended o the domain of sociology; talten in the boad sense as the science of histoical, cultual, and economic pocesses. n this way one aives a the esult tha evey sociological assetion which is meaningful, that is to say, in pinciple veifiable, "has as its subjec nae nothing else than the states, pocesses and behavio of goups o of individuals (human o animal), and thei esponses to one anothe and to thei envionment," 12 and consequendy tha evey sociological statement is a physicalistic staement. This view is cha.aceized by Neuath as the thesis of"social behavioism," which he adds to that of "individual behavioism" which we have expounded above. Futhemoe, it can be shown 13 that evey statement of what ae called the "sciences of mind and cultue" is a sociological statement in the above sense, povided it has genuine content. Thus one aives at the "thesis of the unity of science": The division of science into diffeent aeas ests exclusively on diffeences in eseach pocedues and diection of inteest; one must not egmd it 1/.S a matte ofpincipk. On the contay, ajt the banches of scinu:e ae in pincipk of one and the same natue; they ae banches of the unitfl.j science, physics. V The method of logical analysis which we have attempted to explicate by claifying, as an example, the staements of psychology, leads, as we have been able to show only too biefly fo the sciences of mind and cultue, to a "physicalism" based on logic (Neuath): Evey statement of the abovementioned disciplines, and, in geneal, of tnnpiical science as a whole, which is not meely a meaningless sequence of wods, is tansl.tztable, without change of content, into a statement containing only physicalistic ums, and consequently is a physicalistic statement. This thesis fequendy encountes stong opposition aising fom the idea that such analyses violendy and consideably educe the ichness of the life of mind o spiit, as though the aim of the discussion wee puely and simply to eliminate vas and impotant aeas of expeience. Such a conception comes &om a false intepetation of physicalism, the main elements of which we have aleady examined in section V above. As a matte of fact, nothing ean be moe emote fom a philosophy which has the methodological attitude we have chaacteized than the making of decisions, on its own authoity, concening the tuth o f.tlsity of paticula scientific staements, o the desie to eliminate any mattes of fact whatsoeve. The subject matte of this philosophy is limited tq the fom of scientific statmtmts, and the deductive elationships obtaining between them. t is led by its analyses to the thesis of physicalism, and establishes on puely logical gounds tha a cetain dass of veneable philosophical "poblems" consists of pseudo-poblems. t is cetainly to the advantage of the pogess of scientific knowledge that these imitation jewels in the coffe of scientific poblems be known fo what they ae, and that the intellectual powes which have till now been devoted to a class of meaningless questions which ae by thei vey natue insoluble, become available fo the fomulation and study of new and fuiful poblems. That the method of logical analysis stimulates eseach along these lines is shown by the numeous publlcaions of the Vienna Cicle and those who sympathize with its genetal point of view (H. Reichenbach, W. Dubislav, and othes). n the attitude of those who ae so bittely opposed to physicalism, an essential ole is played by cetain psychological facos elatiog to individuals and goups. Thus the contast between the constucts (Gehilde) developed by the psychologist, and those developed by the physicist, o, again, the question as to the natue of the specific subjec matte of psychology and the cultual sciences (which pesent the appeaance of a seach fo the essence and unique laws of "objective spiit") is usually accompanied by a stong emotional coloing which has come into being duing the long histoical development of a "philosophical conception of the wold," which was consideably less scientific than nomative and intuitive. These emotional factos ae still deeply ooted in the pictue by which ou epoch epesents the wold to itself They ae potected by cetain affective dispositions which suound them like a ampat, and

6 172 A Histoical ntoduction to the Philosophy of Mind fo all these easons appea to us to have genuine content-something which a moe penetating analysis shows to be impossible. A psychological and sociological study of the causes fo the appeaance of mese "concomitant factos" of the metaphysical type would take us beyond the limits of this study, 14 but without tacing it back to its oigins, it is possible to say that if the logical analyses sketched above ae coect, the fact that they necessitae at least a patial beak with taditional philosophical ideas which ae deeply dyed wim emotion can cetainly not jusify an opposition to physicalism-at least if one acknowledges that philosophy is to be something moe than the expession of an individual vision of the wold, that it aims at being a science. NOTES 1. now conside the type of physicalism outlined in this pape as too estictive; the thesis that all statements of empiical science ae tanslatabk, without loss of theoetical content, into the language of physics, should be eplaced by the weake assetion that all staements of empiical science ae educihk to sentences in me language of physics, in the sense that fo evey empiical hypothesis, including, of couse, those of psychology, it is possible to fomulate cetain test conditions in tems of physical concepts which efe to moe o less diectly obsevable physical attibutes. But those test conditions ae not asseted to exhaust the theoetical content of the given hypothesis in all cases. Fo a moe detailed development of this thesis, cf. R. Canap, "Logical Foundations of the Unity of Science," epinted in A. Maas, ed.,lntmtionality. Mind, and Language (Ubana: Univ. of llinois Pess, 1972). 2. Tactatus Logico-Philosophicus (London, 1922). 3. A ecent pesentation of symbolic logic, based on the fundamental wok of Whitehead and Russell, Pincipia Mathnnatica, is to be found in R. Canap, Abiss de Logistik (Vienna: Spinge, 1929; vol. 2 of the seies Schiftm zu W'tssmschaftlichm Wetauffiumng). t includes an extensive bibliogaphy, as well as efeences to othe logistic systems. 4. The following ae some of the pincipal publications of the Vienna Cicle on the natue of psychology as a science: R. Canap, Scheinpobkme in de Philosophie: Dm Femdpsychische und des &alismussteit (Leipzig: Meine, 1928); De Logische Aufoau de Welt (Leipzig: Meine, 1928) [English tans.: Logical Stuctue of the Wold (Bekeley: Univ. of Califonia Pess, 1967)]; "Die Physikalische Spache als Univesalspache de Wissenschaft," Ekmntnis, 2 ( ), [English tans.: The Unity of Science (London: Kegan Paul, 1934)]; "Psychologic in physikalische Spache," Ekenntnis, 3 ( ), [English tans.: "Psychology in Physical Language/ in A.J. Aye, ed., Logical Positivism (New Yok: Fee Pess, 1959)]; "Uebe Potokollsaetze," Ekmntnis, 3 ( ), ; 0. Neuath, "PotokoUsaette," Ekenntnis, 3 ( ), [English tans.: "Potocol Sentences," in Logical Positivism]; Einheitswissmschaft und Psychologie (Vienna: Spinge, 1933; vol. of the seies Einhitswissmschafo. See also the publications mentioned in the notes below. 5. P. Oppenheim, fo example, in his book Die Natuelkhe Odnung de Wwmschaften Oena: Fische, 1926), opposes the view that thee ae fundamental diffeences between any of the diffeent aeas of science. On the analysis of "undestanding," cf. M. Schlick, "Eleben, Ekennen, Metaphysik," Kantseudim, 31 {1926), Fo futhe details see the statement of one of the foundes of behavioism: J.B. Watson, Behavioism (New Yok: Noton, 1930); also A.A. Roback, Behavioism and Psychology (Cambidge, Mass.: Univ. Bookstoe, 1923); and A.P. Weiss, A Theoetical Bmis of Human Behavio, 2nd ed. ev. (Columbus, Ohio: Adams, 1929); see also the wok by Koehle cited in note 11 below. 7. Space is lacking fo futhe discussion of the logical fom of test sentences (ecently called "potocol sentences" by Neuath and Canap). On this question see Wittgenstein, Tactatus Logico-Philosophicus, as well as the aticles by Neuath and Canap which have appeaed in Ekmntnis (above, note 4). 8. Two citical comments, 1977: (a) This efeence to veification involves a conceptual confusion. The thesis which the peceding consideations wee intended to establish was clealy that the statement "Paul has a toothache" is, in effect, an abbeviated expession of all its test sentences; not that it expesses the claim (let alone the "fact") that all those test sentences have actually been tested and veified. (b) Stictly speaking, none of the test sentences just mentioned is implied by the statement "Paul has a toothache": the latte may be tue and yet any o all of those test sentences may be false. Hence, the peceding consideations fail to show that the given psychological statement can be "tanslated" inca sentences which, in puely physical tems, descibe maco-behavioal manifestations of pain. This failue of the aguments outlined in the text does not peclude the possibility, howeve, that sentences ascibing Cal G. Hempel 173 pain o othe psychological chaacteistics to an individual might be "tanslatable," in a suitable sense, into physical sentences ascibing associated physical mico-states o mico-events to the nevous system o to the entie body of the individual in question. 9. "Soiologie im Physikalismus," Ekmntnis, 2 ( ), , paticulaly p. 411 [English tans.: "Sociology and Physicalism, "in A.J. Aye, ed,, Logical Positivism]. 10. Canap, De Logische Aufoau de Welt; pp ; id. Scheinpobleme in de PhibJsophie. See also note 4 above. 11. A caeful discussion of the ideas of socalled "intenal" behavioism is to be found in Psychologische Pobkme by W. Koehle (Belin: Spinge, 1933). See paticulaly the fust two chaptes. 12. R. Canap, "Die Physikalische Spache als Univesalspache," p See also: 0. Neuath, Empiische Soziologie (Vienna: Spinge,. 1931; the fouth monogaph in the seies Schiftm zu wissenschaftlichen Weltauffmsung). 13. See R. Canap, De Logische Aufoau de Welt; pp and , as well as the woks cited in the peceding note Neuath has made imeesting contibutions along these lines in Empiische Soziologie and in "Soziologie im Physikalismus" (see above, note 9), as has R. Canap in his aticle "Uebewindung de Metaphysik duch logische Analyse de Spache," Ekenntnis, 2 ( ), [English tans.: "The Elimination of Metaphysics though Logical Analysis of Language," in A.J. Aye, ed., Logical Positivism].