The Molyneux Problem Author(s): John W. Davis Reviewed work(s): Source: Journal of the History of Ideas, Vol. 21, No. 3 (Jul. - Sep., 1960), pp. 392-408 Published by: University of Pennsylvania Press Stable URL: http://www.jstor.org/stable/2708144 . Accessed: 21/02/2013 03:02 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. University of Pennsylvania Press is collaborating with JSTOR to digitize, preserve and extend access to Journal of the History of Ideas. http://www.jstor.org This content downloaded on Thu, 21 Feb 2013 03:02:05 AM All use subject to JSTOR Terms and Conditions THE MOLYNEUX PROBLEM BY JOHNW. DAViS "Prepareret interrogerun aveuglene, n'efut point et6 une occupation in- dignedes talens reunis de Newton,Descartes, Locke et Leibnitz."-Diderot I. INTRODUCTION The generalconditions of the Molyneuxproblem are as follows: assumea manborn blind, w howhile blind has learnedto distinguish a globefrom a cube. Wouldhe, upon havinghis sightrestored, be able to distinguishthe globefrom the cube by sightbefore he had touchedthem? Because of its theoreticalsignificance the problem was discussedby someof the mosteminent thinkers of the XVIIIth centuryincluding Locke, Berkeley,Leibniz, Voltaire, Diderot, and Condillac. Likemany great problems, it has notbeen solved, appear- ing full-blownas a subjectof occasionalcomment throughout the XIXth century,al thoughby thenthe terms of reference of the issues at stakebecame that of thenativism-empiricism controversy in psy- chology.The attitudestoward the problem are worthtracing in some detail because of the light thrownon some importantissues of XVIIIth-centurytheories of knowledge,and becauseof the instruc- tivenessof its resultsin the historyof psychology.'The present articledoes not pretend to be a fullchronicle of the problem.I have tried,however, to takeaccount of all significantdiscussions. The problemis primarilyan epistemologicalone, involving the na- tureof the transitionfrom sensation to judgment.A definitivean- swerto theproblem would presumably provide an answerto someof themost vexing questions of empiricism, sensationalism and rational- ism,as we have cometo name theseissues. Empiricismis the doc- trinethat all our ideas-the materialsof knowledge-comefrom ex- perience. As Locke,who may serve as ourprincipal exponent of the empiricaldoctrine, expounded it, experiencehas twosides: sensation and reflection.On thisview, all knowledgearises in connectionwith senseexperience, but themind, through its simpleideas of reflection, is able to workon the data thusfurnished by the sensesa nd at the sametime is able to be awareof its ownoperations. Sensationalism, a variantof empiricism with Condillac as its prototype,is an attempt 1 The Molyneuxproblem is also one of the main sourcesof the conceitof the blindman so popularin XVIIIth-centuryliterature, although this paper does not treatthis phase of the problem. See MarjorieHope Nicolson,Newton Demands theMuse (Princeton,1946) 83-85,and KennethMacLean, John Locke and English Literatureof theEighteenth Century (New Haven,1936), 106-108and passim. It shouldbe notedthat Miss Nicolsonerrs in statingthat Molyneuxdiscussed this problemmore fully in the DioptricaNova. Thereis no mentionof the problem eitherin theedition of 1692or in thereprint of 1709. 392 This content downloaded on Thu, 21 Feb 2013 03:02:05 AM All use subject to JSTOR Terms and Conditions THE MOLYNEUX PROBLEM 393 to reducethe Lockean dualism of sensation and reflection to a monism in whichsensation is primaryand reflectionis onlytransformed sen- sation. For the sensationalist,all knowledgeis givenin sensation. Rationalism,as held forexample by Leibniz,would grant that data are obtainedfrom both sensation and reflection,but wouldalso insist thatcertain knowledge can be obtainedonly by meansof self-evident principlesof whichsensation and reflectiongive us onlya confused and provisionalview. Statedin thisway, it can be seenreadily that those who answered theMolyneux problem negatively would tend to be classifiedas either empiricistsor sensationalistsand thatthose who gave an affirmative answerwould tend toward rationalism. One must,of course,beware ofreading more precision into this classification than it willbear, since the terms'rationalism' and 'empiricism'are best understoodas names forgeneral tendencies in thoughtand not as descriptiveof mutuallyexclusive alternatives. II. MOLYNEUX, LOCKE, AND BERKELEY: THE NEGATIVE ANSWER WilliamMolyneux, author of the Dioptrica Nova (1692), an influ- entialearly XVIIIth-century treatise in optics,was a manvery much awareof theproblems of theblind because of his wife'sloss of sight. He proposedwhat he referredto as a 'jocose problem'in a letterto Lockeon March2, 1692: Supposea manborn blind, and nowadult, and taught by histouch to distin- guishbetween a cube and a sphere(suppose) of ivory,nighly of the same bigness,so as to tellwhen he feltone and t'other,which is the cube,which the sphere. Supposethen, the cube and sphereplaced on a table,and the blindman to be madeto see; querywhether by his sight,before he touch'd tllem,he couldnow distinguish and tell whichis the globe,which the cube. I answernot; fortho' he has obtainedthe experience of how a globe,how a cubeaffects his touch, yet he has notyet attained the experience, that what affectsmy touch so or so, mustaffect sight so or so; or thata protuberant anglein thecube that press'd his handunequally, shall appear to his eye as it doesin thecube.2 In the latter part of March of the same year Locke replied to this letter,saying that " your ingeniousproblem will deserve to be pub- lished to the world."3 ThereuponLocke insertedthe problemin the secondedition (1693) and all remainingeditions of the Essay Con- cerningHuman Understanding,presenting Molyneux's problem as just given without substantial difference. Molyneux refersto his problembriefly once more in print.4 2 SomeFamiliar Letters between Mr. Lockeand severalof hisFriends (London, 1708),37-38. 3Ibid.,43. 4 In Decemberof 1695,after his correspondencewith Locke had ripenedinto warmfriendship, Molyneux enclosed a letterfrom Edward Synge to a Dr. Quayl,in This content downloaded on Thu, 21 Feb 2013 03:02:05 AM All use subject to JSTOR Terms and Conditions 394 JOHN W. DAVIS It is generallyassumed that Locke's position and thatof Molyneux in regardto thequery are identical,since both reply to it in thenega- tive. Both Jurin5 and Priestley6 concludequite correctlythat al- thoughMolyneux and Lockeagreed on theanswer their grounds seem different.Locke, in commentingupon Molyneux's query, says: I agreewith this thinking gentleman ... and am of opinionthat the blind man,at firstsight, would not be able withcertainty to say whichwas the globe,which the cube, whilst he onlysaw them;though he couldunerringly namethem by histouch, and certainlydistinguish them by thedifference of theirfigures felt. 7 As Jurinpoints out, in Molyneux'soriginal statement of the problem, the blind man is debarredonly fromtouching the globe and the cube, whereas Locke imposes the additional conditionthat the blind man make the identificationat firstsight, i.e., presumably wlthout walking aroundand viewingthe objects from various sides. The possibledif- ferencesin the solutionthus generatedare betterconsidered after Leibniz'saffirmative solution to theMolyneux problem has beencan- vassed. Berkeleycommented on theproblem negatively both in itsoriginal versionand in versionshe constructedto exploitfor various philo- sophicalpurposes. 8For Lockethe Molyneux problem served to illus- tratethe " mentalinterpretation ofthe data ofsense "; 9 forBerkeley it playsa muchwider role. Cassirergoes so faras to say that" The New Theoryof Vision,which forms the prelude to Berkeley'sphilos- ophy,and containsall his ideas implicitly,is nothingbut an attempt at a completesystematic development and elucidationof Molyneux's problem."10 In Berkeley'searly notebooks, the PhilosophicalCom- mentaries(written from 1707-1708), there are thirteenspecific refer- encesto the problem;Berkeley uses it fora varietyof purposes,the whichSynge answered the questionin the affirmative.After noting that he has encloseda copyof Synge'sletter, Molyneux adds thathe is not budgedby Synge's contentions. r JamesJurin (1684-1750) edited Vols. XXXI-IV of the PhilosophicalTrans- actions. In an age of greatpolemicists, he was one of its best-known.He was an ardentNewtonian and a defenderof thetheory of fluxions,which involved him in a famouscontroversy with Berkeley. 6 JosephPriestley (1773-1809), Vision, Light, and Colours(London, 1772), 720. 7John Locke,Essay ConcerningHuman Understanding, ed.A. C. Fraser(Oxford, 1894),I, 187. 8 Berkeley'sremarks on the Molyneuxproblem in his publishedwritings should be studiedin conjunctionwith Luce's referencesand commentson entries27 and 28 of thePhilosophical Commentaries, ed. A. A. Luce (London,1944). Cf. ColinTur- bayne,"Berkeley and Molyneuxon RetinalImages," this Journal,XVI (1955), 339-355. 9 Ibid.,editor's note to entry27, 326. 10Ernst Cassirer, Philosophy of theEnlightenment (Princeton, 1950), 109. This content downloaded