On the Relation Between Psychological and Physical Concepts

READINGS IN

PHILOSOPHICAL AI{ALYSIS SE LI 1CTED

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On the Reletion Betu'een Psychologicaland

PhysicalConcepts* MORTTZ SCHLICK

I in ettempts co frcc the Cartesian lacking has not been philosophy Recent

problemof the relationbetu'eennrind and body frorn its mctaphysical ical subsub. obscurities,by refusingto poseit in terrnsof mentaland physical the harntlcss the in gcnwith tne wltn harntlcss natllllcssquestlon to horv. norvrIn instead.with lnstead, scnstances: besinnins. euesrionaslo beginning, beglnnng,instead, stances; stances; concepts. That tlris eral,u'e havecomeby our physicalandpsychological is acruallythe correctrvry to approachthe solutionof thc problcm,I havc no doubr. Indeed,I am convinced tlrat the problcrn will alrcady bc solvcd rhe momcnt s'e becorne conrpletely clear as to the rulcs in eccordance wich rvhich we employ thc rvords "mental" and "physical." For wc shall then grasp the proper mcening of all physicdl and psychologicalpropositions, and in doing so *'ill know in rvhat relation thc propositions of physics stend to tlrose of psychology. When Descartcssought to dcfinc his "corporcal substance"bv spccifying the anribute "extensiot' as its characteristic mark, hc took thc fimt srep in a direction s'hich must be follos,ed to thc cnd beforc onc can hope to form a clear idca of the propertieswhich bclong to all "physicirl" concepts, ancl to thesc alone. "Dxtensio" rcfers, of coursc, to sptrtigl cxtcnsion; and it is indeed possiblcconfidcntly to assertthat an analvsis yiclds rvithout furthcr ado a dcfinidon of the concept of spatialercrension of the concept"phvsical." The problern,hon ev€r, is by no mcansso simple that it sufficcsto sav "whatever is spadallv extended is physical," for thcre arc rvords which rnoke senseu'hen conrb,incdn'ith thc prcdicatc "spatiallv cxtcndcd," and r*'hich neverthelessrefer to "mcntal" statcs;such words, for exanrple,as t'tactual scrlsation,ttt'pain,t' etc, Consequently,the diftcr"visual irnage,t' cnce \\-e are scckingcan bc found along the ntrcvc lincs only if thc u'ord anclphvsicnl usrlgcs. "cxtcntlcrl" hasclificrcrrtnrconingsin its ps.r'chological Is this rhc cnsci l)o I hrrvcthe snutcthirrgin urind.or sontcrltingtlillcr'cnt. rvhcn Isrrv of a plrin tlrirt it sprcirdsot'cr il cct't,tirlil'cl. rls('rlrrl):rt'('(l i t p l rl si t' :rlol ri ct' t,fot' t' x Io rr lr c r rI as c r ilr cn t' c ft:ti ns p :tti i rlc x tc rt:;i t.t' to ' l rrrrsl rtr.rl l rr' \1 ', S- r n' l tl.tr lir tr ,l r r itlr tln. l.ir r ,l tu t r tr t,,.i ,r tr of l l tr t l r . r ' . l r t.r..,,l A 'ri ti r,',/,'Sr r r l/,,:,,' I lr c,qls,i11.1l r r lr lr r tlr lr r ltr',1 i r t r ,115-

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DATA, REALITY, AND qU! M!ND-B0DY PRoBLEM 39+ ample my hand? Is the visual imag€ of the moon "cxrcndcd" in the samc senseas the moon itselfl Do my visual imprcssionson looking at a book have extensionin the samesenseasthe tactual imprcssionsI obrain by holding it in my handi The answeringof thesequestionsis the first step in the processof clari fying our concepts,nay the second,-for rhe lirsr and more difficult stcp is to ask tlresequestionsat all. This step \r'ns not taken by Descartesnor by thoseu'ho follow him,-the possibilitynot cvcn occurring to them that the word "etctefllio" is usedin more than one sense.lt would therefore not be correct to describetheir use of this rlord bv saying that rhev took it to have rhe sdntemeaning in significrntl.v different cases.'fhey didn't evcn sce that there u'ere differcnt cases,Belkeley alone u'as a famo[s exception. He posed rhe third of our three questions.The 6rst trvo couldn't be raisedin his system,since a by no meansinconsiderablepart of his philosophyconsistccl€.\acdyin a proof thar thesequestionsdo not exist, For hirn therc is no otlrcr kind of extensionthan that rvhich can of sight and touch; indeed. in Berke"bc nttriburcclto thc rcprcscntariorls lcy's philosophy it is ilrcady a uristakeio speakof theseas "represenratiurtg" sirrccthcre is notlring rrhiclr is copicd by them and is their original. Kant, u'ho plrikrsoplriz.cd so rrruch latcr than Berkeley, believed he had nothing to lclrn frorrr hirrr, nrrd didn't succeedin raising our questions. He invarinbly spcaks,ns did L)cscartes before hirn, of extension,of Space, and omits anv invcstigationas to s'hether it may not be necessaryto discinguishbcni'een sevEralspice-concepts;first, l,ecrn'een the phyiical and the psychological,and under the latter, benreen visual-space,tactualspace,etc. This ncglect had unfortunate consequences for Kant's phiklsophy of geometry,and, through this, for his s,r'stem asa whole, Physical sPsce,the spnceof nature,is for him alsopsychologicalspace,sincenature is for him "rnere appearance,"that is, mere "idea," and this is a psychoIogical term. It is possiblcto regard Kant's distinction between "outer" and "inncr" senseas an attempt to drarv a boundary betn'een the physical and thc mental. His doctrine that Space,the form of intuition for outcr scrrsc,is lacking in the caseof inner senseis indeed reniniscent of Dcscartcs,rrs wcll as a forerunner of recent a$emDts to characterizethe nrcntnl rrs sirrrply ttrc non-spatial.It is said that even therc tlre nrcntal hns to rlo uitlr tlrc sprtill (in idcasnnd pcrccption),it is itsclf notr-spiltiirl.'l'lrc irlcrr of rt rrrl tt'i:rrglcis itsclf ncitlrcr rctl nor trirutgul,rr,nor is thc pcrcclttiorr o l ' :rr rt ' r t t . nt lt . tolr l icc ti ts c l f c x rc rtrl c rl . 'Ilr is : r ' . ' , t ' r t iororr r ' (' si l s l rp p c l rl l rrrt'o cf p l :rrrs i l ri l i tl ' totl tc l ' :rt' ttl r:rttl rt. tto tr ls " 1x r c r ' pt ion " :rttrl" i .l c l t" :trr' ;rtrrl ' i !l rro rrs. l !1' l l tcrtr orrt' (' ;ul t' (' l (' t' t if lt c t' f r r

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k' :ttc tnrrisc,l tlre r;rr t ' , , t i, ritr r\ t o t lr c ir r s t ili: r lllir l r r l ll r i s r l i r t i r t c t i o n l r r 't r r l t 'r r (' rrn t('rtl;rrrrl:rt't, u nr l lir r r it ( , ur s c luc st o y r ir r t int l o u t t h i l t s u f c l y i l l i r s l ocr'ru'rcrl ro us t():\lx'Jli {,f nrl nct ()f pcr('cl)tion-nntl, lirtcr, of irrr;rgirrg ' r'nlv irftcr \re h:rtl g:rincd thc knoslctlgc that thc occurrcncc of "contclrts" is sr,nlcho\r, dc;lcndcnt on proccsscs in thc scnsc orgurs, arrd,

frrrtlrcnrrorctlmt thcsc proccsscsarc physical.) One can certairily not say of thc contcnts of pcrception-at least in thc casesof sight and touch -thrt thcv are "non+patial"; rather they are beyond doubt cxtcnded.Indcctl it is from them that rve first derive this concept, Neverthclcsstrve do not meenthe sanreby "extension"in psychological :rnd ph'r'sic:rlcontexts.In order to make the difference clear it is bcst to cxanrineexactly thosecaseswherc it is nrostdiffcult to distinguishpsychokrgical from phvsical space.We askcd above if, for exanrplc.a pain is crtcnded in the samesens€as is a physical obiect, sey, my hand. llut what about the caservherc the pains arc in mv hand itsclf, rvhcrc my rvholc hand aches?Do u'e not have here a mental datum the spadalcxtcnsionof which is identical rvith that of the phvsical object u'hich is "my hand"l The ansrver is, "absolutely not!" Pain has its ou'n space iust as visunl scrtsationshave theirs and as do serx;ationsof touch. Thc fact that scvcral sensationsof pain can occur sirmtltaneously is sufficient ro require us to spcak of a "pain-space."Every arrangementof simultaneousitcms is a sidc-by+ide (as opposedto e sequcncc)end it is customary to cell such facts "spatial." It is experiencervhich first brings about the coiirdinatiorr of the sevcrnlspccesof vizual and tactual sensations, feclingnof pain, etc. This can bc rrrafeto standout nlost clearlv by conceivingof a man who livesin comptetciarkness anclcomplete abienie of motioi. Hc rvould bc acquainteds'ith neitlrcr visual nor tactual sensations,but he could very rvell have "pain thr