1987. Feyerabend_Putnam on Incommensurability

8/12/2019 1987. Feyerabend_Putnam on Incommensurability

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Brit.J. Phil. Sci. 38 (1987), 75-92 Printedn GreatBritain 75

DiscussionsA RETRACTION OF 'A GEDANKEN EXPERIMENT TO MEASURE THEONE-WAY VELOCITY OF LIGHT'My (Nissim-Sabat, 1984) paper proposing a method for measuring thespeed of light on a one-way trip is wrong and I am retracting it. Briefly, Ihad proposed that if one had two identical clocks at A and B respectivelyone could measure the speed of light from A to B: the fact that the twoclocks could not be synchronized would be remedied by the interchange ofthe positions of the two clocks. Winnie [1970] has shown that if the twoclocks are transported in exactly the same way (i.e., with identical velocitiesas measured by round trip methods), then the two clocks would showexactly the same time lapse (including relativistic time dilation) for theirrespective trips. Thus I had argued that any inherent time differencebetween the two clocks having been preserved, its effect would have beencancelled out after the interchange. Yet, following Winnie's reasoning, onecan show that all observations made this way would lead experimenters toconclude that the velocity of light from A to B is the same as that from Bto A, regardless of whether this is indeed the case. One objection that onecan make to my method is to point out that I had assumed that laboratorybound observers would necessarily agree with the moving clocks that thetrip from A to B took the same time as that from B to A.I was led to the above reconsiderations by the objections of an anonymousreferee for the American fournal of Physics to another synchronizationmethod I had presented.

CHARLES NISSIM-SABATNortheastern Illinois University

REFERENCESNISSIM-SABAT, C. [1984]: 'A Gedanken Experiment to Measure the One-Way Velocity ofLight'. Brit. J. Phil. Sci., 35, 62-64.WINNIE,J. [1970]: 'Special Relativity Without One-Way Assumptions'. Phil. Sci., 37, 81-99and 223-238.

PUTNAM ON INCOMMENSURABILITY(I) In Putnam [1981], p. I 14 Putnam asserts that 'both of the two mostinfluential philosophies of science of the Twentieth Century . . . are self


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76 P. Feyerabendrefuting'. The philosophies he has in mind are logical positivism and thehistorical approach. I shall discuss an idea that belongs to the latter viz.incommensurability and I shall show that while the idea may have unusualconsequences, self refutation is not one of them.

(2) According to Putnam 'the incommensurability thesis is the thesisthat terms used in another culture, say, the term "temperature" as used bya seventeenth century scientist, cannot be equated in meaning and referencewith any terms or expressions we possess' ( 14). I shall call the incom-mensurability thesis as defined in this statement T.To refute T Putnam points out,(A), that 'if [T] were really true, then we could not translate other languages-oreven past stages of our language-at all' (I 14), adds,(B), that 'if Feyerabend . . . were right, then members of other cultures, includingseventeenth century scientists would be conceptualisable by us only as animalsproducing responses to stimuli' and concludes,(C), 'To tell us that Galileo has "incommensurable" notions and then to go on andto describe hemat length is totally incoherent' (I 14f-Putnam's italics).

(3) A, B and C rest on the following two assumptions: understandingforeign concepts (foreign cultures)[i] requires translation and

[ii] a successful translation does not change the translating language.Neither [i] nor [ii] is correct. We can learn a language or a culture from

scratch, as a child learns them, without detour through our native tongue(linguists, historians and anthropologists, having realised the advantages ofsuch a procedure now prefer field studies to the reports of bilingual infor-mants). And we can change our native tongue so that it becomes capableof expressing alien notions (successful translations always change themedium in which they occur: the only languages satisfying [ii] are formallanguages and the languages of tourists).Modern lexica exploit both possibilities. Instead of the semantic equa-tions that formed the basis of older dictionaries they employ researcharticles of an open and speculative nature. (An example are the introductionand the major research articles of Snell [1971].) Analogies, metaphors,negative characterizations, bits and pieces of cultural history are used topresent a new semantic landscape with new concepts and new connectionsbetween them. Historians of science proceed in a similar way, but moresystematically. Explaining, say, the notion of 'impetus' in I6th and 17thcentury science they first teach their readers the physics, metaphysics,technology, even the theology of the time, i.e. they again introduce a newand initially unfamiliar semantic landscape and then show where impetusis located in it. Examples are found in the work of Pierre Duhem, AnnelieseMaier, Marshall Clagett, Hans Blumenberg and, for other concepts, thework of Ludwik Fleck and Thomas Kuhn.

Translating a language into another language is in many ways like con-


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78 P. Feyerabendreceived then we have the situation alluded to in (C), but defused, for theEnglish with which we start is not the English with which we conclude ourexplanation.

(5) Azande ideas already exist in a spoken language and English notionswere changed to accommodate them. There are other cases where linguisticchange introduces a novel and as yet unexpressed point of view. The historyof science contains many examples of this kind. I shall explain the matterby taking an example from the history of ideas.In Iliad 9, 225ff Odysseus tries to get Achilles back into the battle againstthe Trojans. Achilles resists. 'Equal fate' he replies 'befalls the negligentand the valiant fighter; equal honor goes to the worthless and to the vir-tuous' (3 I8f). He seems to say that honor and the appearance of honor aretwo different things.The archaic notion of honor did not allow for such a distinction. Honor,as understood in the epic was an aggregate consisting of partly individualpartly collective actions and events. Some of the elements of the aggregatewere: the position (of the individual possessing or lacking honor) in battle,at the assembly, during internal dissension; his place at public ceremonies;the spoils and gifts he received when a battle was finished and, naturally,his behavior on all these occasions. Honor was present when (most of) theelements of the aggregate were present, absent otherwise (cf. II. 12, 3 Ioff--Sarpedon's speech).Achilles introduces a different point of view. He was offended by Aga-memnon who took his gifts. The offence created a conflict between theindividual and the collective ingredients of honor. The Greeks who appealto Achilles, Odysseus among them, illustrate the customary resolution of theconflict: Achilles' gifts have been returned, more gifts have been promised,harmony has returned to the aggregate, honor has been restored (519, 526,602f). So far we are squarely within tradition. Achilles moves away from it.Pushed along by his lasting anger he perceives an equally lasting imbalancebetween personal worth and social rewards. What he has in mind not onlydiffers from the traditional aggregate, it is not even an aggregate for thereis no set of events that guarantees the presence of honor as he now sees it.Using Putnam's terminology we can say that Achilles' idea of honor is'incommensurable' with the traditional idea. And indeed, given the epicbackground the short excerpt I quoted from Achilles' speech sounds asnonsensical as the statement 'equal time needs the fast and the slow to reachthe goal'. Yet Achilles introduces his idea in the very same language thatseems to exclude it. How is that possible?It is possible because, like Evans-Pritchard, Achilles can change conceptswhile retaining the associated words. And he can change concepts withoutceasing to speak Greek because concepts are ambiguous, elastic, capableof reinterpretation, extrapolation, restriction, or, to use a term from thepsychology of perception, concepts like percepts obey figure-groundrelations.


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Putnam on Incommensurability 79For example, the tension between the individual and the collectiveelements of honor that was caused by Agamemnon's deed can be seen in atleast two ways, as involving ingredients of equal weight, or as a conflictbetween fundamental and more peripheral elements. Tradition acceptedthe first view or, rather, there was no question of a conscious acceptance-

people simply acted that way: 'With gifts promised go forth. The Achaianswill honor you as they would an immortal ' (602f). Achilles driven by hisanger magnifies the tension so that it turns from a transitory disturbanceinto a cosmic rift (figure-ground relations often change as a result of strongemotions; this is the principle of the Rohrschach-test). The extrapolationdoes not void his speech of meaning because there exist analogies for whathe is trying to express. Divine knowledge and human knowledge, divinepower and human power, human intention and human speech (an exampleused by Achilles himself: 312f) are opposed to each other as Achillesopposes personal honor and its collective manifestations. Guided by theanalogies his audience is drawn into the second way of seeing the tensionand so discovers, as Achilles did, a new side of honor and of archaic morality.The new side is not as well defined as the archaic notion-it is more aforeboding than a concept-but the foreboding produces new ways ofspeaking and thus, eventually, clear new concepts (the concepts of somePresocratic philosophers are endpoints of this line of development). Takingthe unchanged traditional concepts as a measure of sense we are of courseforced to say that Achilles speaks nonsense (cf. Parry [1956] for this point;cf. also Feyerabend [1975], 267). But measures of sense are not rigid andunambiguous and their changes are not so unfamiliar as to prevent thelisteners from grasping what Achilles has in mind. Speaking a language orexplaining a situation, after all, means both following rules and changingthem; it is an almost inextricable web of logical and rhetorical moves.From what has just been said it also follows that speaking a languagegoes through stages where speaking indeed amounts to merely 'makingnoises' (Putnam [I98i], 122). For Putnam this is a criticism of the viewshe ascribes to Kuhn and myself. For me it is a sign that Putnam is unawareof the many ways in which language can be used. Little children learn alanguage by attending to noises which, being repeated in suitable sur-roundings, gradually assume meaning. Commenting on the explanationswhich his father gave him on logical matters Mill writes (Lerner [19651,21): 'The explanations did not make the matter clear to me at the time;but they were not therefore useless; they remained as a nucleus for myobservations and reflections to crystallize upon; the import of his generalremarks being interpreted to me, by the particular instances which cameunder my notice afterwards.' Saint Augustine advised parsons to teach theformulae of the faith by rote adding that their sense would emerge as aresult of prolonged use within a rich, eventful and pious life. Theoreticalphysicists often play around with formulae which do not yet make any senseto them until a lucky combination makes everything fall into place (in the


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80 P. Feyerabendcase of the quantum theory we are still waiting for this lucky combination).And Achilles, by his way of talking, created new speech habits whicheventually gave rise to new and more abstract conceptions of honor, virtueand being. Thus using words as mere noises has an important functioneven within the most advanced stages of speaking a language (cf. Fey-erabend [ 19751, 270).One of the scientists who was aware of the complex nature of explanatorytalk and who used its elements with superb skill was Galileo. Like AchillesGalileo gave new meanings to old and familiar words; like Achilles hepresented his results as parts of a framework that was shared and understoodby all (I am now speaking of his change of basic kinematic and dynamicalnotions); but unlike Achilles he knew what he was doing and he tried toconceal the conceptual changes he needed to guarantee the validity of hisarguments. Chapters 6 and 7 of my [1975] contain examples of his art.Taken together with what I have said up till now these examples show howit is possible to assert, without becoming incoherent, that the Galileannotions are 'incommensurable' with our own 'and then to go on and todescribe them at length'.

(6) They also solve Putnam's conundrum about the relation betweenrelativity and classical mechanics. If T is correct, says Putnam, then thesense of statements that occur in a test of either relativity or classicalmechanics cannot be 'independent of the choice between Newtonian andEinsteinian theory'. Moreover, it is then impossible to find equations ofmeaning between 'any word in ... Newtonian theory [and] any word in ...general relativi[ty]' (i 16). He infers that there is no way to compare the twotheories. The inference is again mistaken. As I mentioned in section 3linguists long ago ceased using equations of meaning to explain new andunfamiliar ideas while scientists always emphasized the novelty of theirdiscoveries and of the concepts used in their formulation. This does notstop them from comparing theories, however. Thus the relativist can saythat the classical formulae, properly interpreted (i.e. interpreted in the rela-tivistic manner) are successful, but not as successful as the full relativisticapparatus. He can argue like a psychiatrist who, talking to a patient whobelieves in demons (Newton) adopts his, the patient's manner of speakingwithout accepting its demonic (Newtonian) implications (this does notexclude the the possibility that the patient will one fine day turn aroundand convince him of the existence of demons). Or he may teach relativityto the classicist like a foreign language and invite him to judge its virtuesfrom within ('having learned Spanish to perfection and having read Borgesand Vargas Llosa, would you not rather write stories in Spanish than inGerman?') There exist many other ways in which the Newtonian and therelativist can and do converse. I have explained them in papers I wrote in1965, some of them in direct response to Putnam's criticisms of that time:Feyerabend [198I], Vol. i, chapter 6, sections 5ff and Vol. ii, chapter 8,section 9ff and appendix. This finishes my response to A, B and C.


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Putnam on Incommensurability 8 1(7) The arguments of the preceding sections were based on T which isPutnam's version of incommensurability. But Putnam's version is not theversion I introduced when examining the relation between comprehensivetheories such as Newton's mechanics and relativity or Aristotelian Physicsand the new mechanics of Galileo and Newton (cf. Feyerabend [1975] 268ffand [1981], Vol. i, chapter 4, section 5). There are two differences. First,

incommensurability as understood by me is a rare event. It occurs onlywhen the conditions of meaningfulness for the descriptive terms of onelanguage (theory, point of view) do not permit the use of the descriptiveterms of another language (theory, point of view); mere difference of mean-ings does not yet lead to incommensurability in my sense. Secondly, incom-mensurable languages (theories, points of view) are not completely dis-connected-there exists a subtle and interesting relation between theirconditions of meaningfulness. In my [1975] I explained this relation in thecase of Homeric Commonsense vs. the language aimed at by the early Greekphilosophers. In [i98I] Vol. i, chapter 4 I explained it in the case ofAristotle-Newton. I should add that incommensurability is a difficulty forphilosophers, not for scientists. Philosophers insist on stability of meaningthroughout an argument while scientists, being aware that 'speaking alanguage or explaining a situation means both following rules and changingthem' (see section 5 of this paper) are experts in the art of arguing acrosslines some philosophers regard as insuperable boundaries of discourse.

PAUL FEYERABENDUniversity of Californiaat Berkeley

REFERENCESEVANS-PRITCHARD,. E. [1976]: Witchcraft,Oraclesand Magic Among theAzande, abridgededition, Oxford, 1976.FEYERABEND,AULK. [1975]: Against Method, London, 1975.FEYERABEND,AUL K. [1981]: PhilosophicalPapers, 2 Vols., Cambridge, 1981.LERNER,MAX [1965]: Essential WorksofJohn Stuart Mill, New York, 1965.PARRY,A. [1956]: 'The Language of Achilles', Trans. & Proc. Amer. Philos. Assoc., Vol. 87,1956.PUTNAM,HILARY1981]: Reason, Truth and History, Cambridge, 1981.SNELL, BRUNO 1971]: Lexikon des FruehgrechischenEpos, Goettingen, 1971.

PAPINEAU ON CAUSAL ASYMMETRY

David Papineau in 'Causal Asymmetry' attempts to provide an account ofcausal asymmetry which does not depend upon the assumption that causesprecede their effects in time [1985]. In place of a temporal-priority view,he introduces a probabilistic analysis. This analysis takes two forms, one

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1987. Feyerabend_Putnam on Incommensurability