Naturalism; Or, Living Within Ones Means

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Naturalism; Or, Living Within One's Means

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tor Henri Lauener's sixtieth birthday Abstract

Naturalism·holds that there is no JUsher access·to truth thaD empiricaDy testable hypotheses. Still it does not repudiate untestablo hypotheses. '!bey fill out iDtendces of 1beo1y and lead tQ furt:helo ~theses that uetestable. A hypothcisis J8 tested by dccfuc:ing. from it and a baCkground of accepted theory, some observation categorical that dOes not folfOwfrom thebackground a1oDo. 'lbis categorical, ageneraIiZed conditiODal compounded of two observation 1SCDteDces, admits in tum of a priDdtive experimental test. . ' . 1'0 o~dODsentoDces themselves,liko apecriesand bird calls, ue in hoJopbrasticUlOciadoD With ranau of noural Jntab. DoqOtadOD of determfnate objects figures neither fa thIa a.uocfation Doria deducing the eategerical from the scientific hypotheses. HeDce tho fndeter. miJIacy of Ieferaace; ~ is puzeJ.y auxiIiaIy to tho st:l1ICtlml Ofthooxy. 'Iiutb. however, is seenstiIlu transcendollt at leastiD this 8eDSO~wesay ofa suporsodcdscientifictheorynotthat it ceased to be true, but that it is found to have been false. . ....

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Names ofphilosophical positionS are a necessary eviL They are necessary because we need tQ refer to a stated position or doctrine from time to time, and it would be tireSOme to keep restating it. Theyare evil in tbat they come to be conceived as deSignating schools ofthoupt, objects of loyalty from within and obj~ of obloquy from without, and hence obstacles, within and without, to the pursuit of truth. In identifying the philosophical position that I call naturalism, then, I shall just be· describing my oWli p(>sition, without prejudice to possibly divergent uses ofthe term.ID Theories and Thlngs I wrote that ~turalism is "therecog"; .• nition that it is ~ science itself, and not in some prior philosophy, that reality is to be identified and described"; again that it is "abandonment of the goal ofa first philosophyprior to natural science" (pp. 21, 67). Th~ ~e­ teriz8tions convey thO. right moQd, but they would fare Poorly in a·debate. How much qualifies as "science itself" and not "some prior philosophy"? • Harvard University, USA

DiaIeciica .

VoL 49, N° 2-4 (1995)

252

W.V.Qaine

It1 science itself I certainly want to indude the farthest flights of physics aDd cosmolo81l as well as experimental psychology, history, and the ~oeial .sciences. Also ~tic:s, insofar at least as it is applied, for it is indispens. able to natural sclence. What thea amIexcluding as "some priorphilosOphy," and why? Descartes' dualism between miDd and body is called metap~ysics, but it could as weD be reckoned as science, however false. He even had.a causal theory of the Interacdoft of mind and body through the pineal gland. If I saw indirect explanatory benefit in positing sensibilia, possibilia,spirits, a Creator, I wouldjoyfully accord theJn scientific status too, on a par with such avowedly scientific posits as quarks and black holes. What then have I banned tinder the name of prior philosophy? . Demarcation is notmypurpose. My pointin the characterizations of naturalism that I quoted is just that the mostwe can reaso:i1ablyseek in support of .an inventory and description of reality is testability of its observable couse. quences in the time-honored hypothetico-deductive way - wher.eof m?re anon. Naturalism need not cast asperSions on irrespoDSlole metaph)'Slcs,. ·however deserved, much less on soft sciences or 011 the speculative reaches of the hard ones, except molar as a firmer basis is claimed for them than the ex" perimental method itself. ~ naturalistic renunciation shows itself most clearly and significantly is in naturalistic epistemology. VarioUs epistemologists, from Descartes to Carnap, had'sought a foundation for ~tu:ral scien~ in mental enti,ties, the flux of raw sense data. It was as if we JDlght first fashion a s~lf-suffiC1ent and infallible lore ofsense data, innocent of referenCe to physical things, and then build out theory of the external world somehow on that finished foundation. The naturalisticepistemologist dismisses this dream ofpriorsense-datum language, arguing that the positing of physical things is itself our indispensable tool for organi?:ing and remembering what is otheJ;Wise, in James' words, a "blooming, buzzing confusion." To account for knowledge of an external thing or event, accordingly, the naturalistic epistemologist looks rather to the external thing or event itself and the causal chain of stimulation from it to one's brain. In a paradigm case, light rays are reflected from the object to one's retina, activating a.patch of nerve endin~, each of which initiates a neural impulse to one or another center of the bram. Through intricate processes within the brain, finally, and abetted by imitation o.f other peopleorbyinstruction, a cbildcomesin tim~ to ~ or assentto s?me rudimentary sentence at the end ofsuch a causal cbain. I call It an observation sentence. Examples are "It's cold"t "It's raining", "(I'hat's) milk", "(1bat'~ a) d~g". . Customarily the experlniental psychologist chooses one or another obj~ or event, from somewhere along such a causal chain, to represent the chain,

Naturalism; Or, Living Within One's Means

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.and this he caDs the stimulus. Usually it is an event of his own devising. In one -~ent it will be a flash or a buzzin the subject's vicinity, and in another it will bean Ice cube or a shock at the subject's surface. For our more general purposes, not linked to any particular experimen~ an.economical ~gy in defiDing the stimuIusis to inteIcept the causal chains jUst at the subject's surface. Nothing Is lost, for it Is omy from that pOint Inward that the chains contribute to the subject's knowledge of the external world. .' Indeed,evenwhat.reaches the. subject's surface is relevant only if it triggers . neural receptOrs.'So we might for our purposes simply identify the subject'~ $timulus, over a given brief moment, with the temporally .orderedset of senSory receptors triggered in that moment . '. . "'.;. Still further economy might be sought by mtercepting the causal chains rather at a ~per level- somewhere within the brain; for even the surface reCeptors that are triggered on any given occasion are largely without relevant effect on the subject's behavior. However, our knowledge of these deeper levels Is still too sketchy. Moreover, as ~ Jncreaslng1y penetrates these . depths, we become aware of complexity and heterogeneity radicaUy a! variance withthe neatsimplicityatthe surface. Each receptor, after all, admits of just two clean-cut states: triggered or no.t .' .Moreover, the behaviorally inelevant triggerings in a global ~ul~ can be defined out anyway, in due course, by appeal to perceptual siJDilarity of stimuli. The receptors whose firing is sa/ientin a given stimulus are the ones that ·it shares with all perceptually similar stimuli. Perceptual ~ty itself 'can be measured, for a given individual,.by reinforcement andextincdon of responses. "":-ul So it seems bestfor present purposes to construe the sub·---' ~~s .n....... us on a giVet1 occasion simply as his global ne~ intake on that ~ut I shaD refer to it only as neural intake, not stimulus, for other notions ofstimulus are wanted in other studies, particularly where diffe~l1t subjects are to get the . same stimulus. Neural intake is private, for subjects do not share receptors. Perceptual similarity, then, is a relation between a subject's neural intakes. Though testable, it is a private affair; the intakes are his, and arepe~ptually more or less similar for him. Perceptualsimilarity is the basis ofallleaming, all habit formation, all expectation by inductionfrom past experience; forwe are innately disposed to expect simDar events to have sequels that are similar to each other. The association of observation sen~ with neural intakes is manymany. Any one of a iange of perceptually fairly similar intakes may prompt tho subject's assent to anyone of a range of semantically kindred sentences. But in contrast to the privacy of neural intakes, and the privacy of theJr ~

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Natul'll1l1ml Or, Living Within Ono" Moan.

W.V. Qulno

~ptUal sUniIarity, observationseiltelices and their sentaDti