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the European sciences. The approach is unabashedly whiggish. The emergence of these styles is part ofwhat Reviel Netz calls cognitive history, and is to be understood in an ecological way. How did a species

2012 Elsevier Ltd. All rights reserved.

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I have been thinking about styles of scientic thinking in theEuropean tradition off and on, ever since I encountered A. C. Crom-bie at a conference in Pisa in 1978 (Crombie, 1981). The late MartinHollis asked for a contribution to a collection of new essays, Ratio-nality and Relativism (Hollis & Lukes, 1982). This volume was inpart a reaction to the new sociology of scientic knowledge ema-nating from Edinburgh, the strong programme of Barry Barnes

son has a history.Aside from Crombie, the initial inspiration may have been Paul

Feyerabends scintillating Against Method (1975). Already by 1970 Iwas falling under the spell of Michel Foucaults early archaeologies,which make one rethink not only the past, but truth itself. ThusFeyerabend and Foucault were buzzing about in a mind disciplinedby Cambridge analytic philosophy. Crombies programme chimedin. Since then I have, very intermittently, used his list of six distinct

Studies in History and Philosophy of Science 43 (2012) 599609

Contents lists available at SciVerse ScienceDirect

P

.e lE-mail address: ian.hacking@college-de-france.frKuschs thorough critical survey in this journal (2010, p.172). Thepresent paper is an update on the styles project occasioned by aworkshop in Cape Town, March, 2011.

1. In the beginning

The title, Language, Truth and Reason, was a riff on Ayerspolemical, logical positivist, masterpiece of 1936, Language, Truthand Logic. The topics of LT&R were exactly those philosophical sta-ples in reverse order: rst reason, then truth, and then language.The novelty, for analytic philosophy, was the realization that rea-Much of itincluding a fair amount of stuff that will never appearin printis listed in the diligent bibliography at the end of Martin2. LT&RWhen citing thi

The phrase styles of scientic rHacking (1982) and cemented in thisreprinted in Hacking, 2002). I remainsketched in those papersalthoughsoning. There has been a fair amounbeen deliberately ephemeral, publish0039-3681/$ - see front matter 2012 Elsevier Ltd. Ahttp://dx.doi.org/10.1016/j.shpsa.2012.07.002, please use the full journal title Studies in History and Philosophy of Science

ng was introduced inal, Hacking (1992; bothitted to the programmethe label, styles of rea-te-ying since. This hast all, in obscure places.

and David Bloor. Lukes and Hollis did not care for Edinburgh onebit, but thought it deserved serious confrontation. The resulting es-says were arranged from left to right, with the staunchly relativistBarnes and Bloor at the far left, with (to my surprise) my piece nextto theirs, and the more rationalist essays coming later in the book.A. C. CrombieReviel NetzBernard Williams

like ours, on an Earth like this, develop a few quite general strategies for nding out about, and altering,its world? At a more analytical level, the project invokes Bernard Williams notion of truthfulness toexplicate the idea that these styles are self-authenticating and without foundations. The paper con-cludes with open questions. What role (for example) have these few fundamentally distinct genres ofinquiry played in the formation of the anomalous Western idea of Nature apart from Man?Language, Truth and Reason 30 years la

Ian HackingDepartment of Philosophy, University of Toronto, 170 St. George Street, Toronto, Ontario

a r t i c l e i n f o

Article history:Available online 28 July 2012

Keywords:Styles project

a b s t r a c t

This paper traces the origiStyles of scientic thinkinging out. A. C. Crombies tembut with a tinge of Paul Fesufcient conditions, but

Studies in History and

journal homepage: wwwll rights reserved.r

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f the styles project, originally presented as styles of scientic reasoning.oing is a better label; the styles can also be called genres, or, ways of nd-te of six fundamentally distinct ones was turned into a philosophical tool,abends anarchism. Ways of nding out are not dened by necessary andbe recognized as distinct within a sweeping, anthropological, vision of

hilosophy of Science

sevier .com/ locate/shpsa

their objects and by their methods of reasoning. (Crombie, 1994,vol. I, p. 83) For short, these may be called mathematical, experi-

ilosstyles of scientic thinking in the European tradition as a tem-plate for the ways in which different methods of inquiry used inthe sciences have their own historical trajectories, and have moul-ded scientic reason and even what counts as true (see the usemade of Bernard Williams in 15 below).

The styles project uses the past as a way to understand the pres-ent. Although it has suggested historical research to others, anddraws on far more historical data than it cites, in itself it adds nonew content to the history of science. The accounts of the past towhich it refers are (disconcertingly for many readers) as often folk-lore as archive-based research. Anthropology, sociology, and cogni-tive science, especially of the more speculative sort, are alsoinvoked. In short, the project is philosophy attentive to, but notawed by, many neighbouring bodies of knowledge and theorizing.

Looking back at the state of play in 1982, the target of the Lukesand Hollis anthology, namely the nascent sociology of scienticknowledge, has turned into the amazingly rich eld of sciencestudies for which we are all enormously grateful. The styles projectwould be happy to be accepted under that umbrella, but it is stilllogic, in a traditional understanding of the word. The very sameLogic as appeared in Ayers title, although not his logic. It is abouttimeless reason except that: We have to acknowledge that reasondid not fall from heaven as a mysterious and forever inexplicablegift, and that it is therefore historical through and through; butwe are not forced to conclude, as is often supposed, that it is reduc-ible to history (Bourdieu 2000, p. 109).

3. Out of anarchy

LT&R described itself as driven by anarcho-rationalism. That wasa tip of the hat towards Feyerabend, who at the time was proclaim-ing himself an anarchist, later retracted to Dadaist. As is so commonin philosophy, retreat to safer ground is a loss. The movement thatcalled itself Dada was brilliant but ippant. Anarchism is stupid butserious, so I prefer that label. A more anodyne name, tting the talkof the day, would have been rationalism without foundations.

There is no deep reason for, or cause of, the appearance at dif-ferent times of a few distinct genres of scientic inquiry, oftendetectable in ancient Greece, and still ourishing. They were bredin a seething culture of groping and grumbling, an agar-agar of talkand technologies (including writing and drawing diagrams). Theybegan to stabilize but also continued to evolve in an endless cycleof contingencies. This anarchic story is not quite that of a randomwalk, but there was no foreordained right route. There is no rea-son why these types of argument have become part of our canonof what we call right reason. But they are our canon. The largergrounds for the canon are not self-consciously rational, and mightbe better described as ecological.

Ecological? On the one hand, scientic thinkingand doingex-ploit human capacities, both mental and physical, which in thecourse of human history we have learned to use and hone. Manycognitive scientists argue that such capacities are innate, and fa-vour a modular approach. Hence each distinct way of nding outabout the world might be grounded in its own cognitive modules.

On the other hand, the discovery of how to use those capacitieshas happened in highly specic local settings at individual mo-ments in time. Yet, since they are grounded in human capacitiesthat are presumed to be universal, they have become part of theheritage of our species. Many would prefer to speak of culturerather than history. Why is this ecological? Because a creaturewith our bodies, including our hands and brains, has discoveredhow to use its endowments to interact with the world in whichit nds itself. These very capacities may have been adapted for

600 I. Hacking / Studies in History and Phquite other purposes. It is rather unlikely that all our ways of nd-ing out were selected for their survival value.mental exploration, hypothetical modelling, probability, taxonomyand historico-genetic explanation. The rst three of these methodsconcern essentially the science of individual regularities, and thesecond three the science of the regularities of populations orderedin space and time. (Crombie, 1981, p. 284)

This list of six was wholly unoriginal, and that is one of its mer-its. It is a conventional organization of popular history of science.The novelty lay in the thought that the list was a stab at an exhaus-tive classication of complementary types of inquiry, a thoughtthat Crombie went on to amplify with a painstaking recital of doc-uments, some familiar, but many arcane. Interspersed in this mid-den are many wise observations, but no one will ever read theentire three volumes of (1994) in their entirety.

Crombie said his styles have distinct objects and methods of rea-soning. These words seem anodyne. The objects with which math-ematics concerns itself are often called, by analytic philosophers,abstract objects, such as numbers, shapes, and groups. The objectswith which taxonomy concerns itself are, for example, the speciesand genera of systematic biology, not mere classications of livingThe throw-away label, anarcho-rationalism, expressed, on theone hand, Leibnizian convictions about reason, and on the otherhand, it acknowledged that the reasoning used in the sciences issedimented anarchy. What once were shifting sands became whatis experienced as rock-hard right reason.

The metaphor of sedimentation comes from Husserls Crisis(1970), but is used in a way opposite to his. In caricature, Husserlthought it was the philosophical task of his time of European crisisto clear away the sediment. That was a specic response to the1930s. We should, he thought, try to recover the original experi-ences underlying fundamental events, such as the discovery ofmathematical proof (the Ursprung of geometry) and Galileos math-ematization of nature. He wanted to remove the sediment, toreach, perhaps, a pre-Galilean state. In our contrary perspective,the sediment, hardened over a long time by great pressures intorock, is a collection of achievements founded on human ingenuity,innate propensities, and interaction with everything. Like any sed-imentary deposit, it may undergo radical change in the future, butit cannot be undone.

4. Not just thinking

LT&R insisted that Crombies styles are not just styles of think-ing. It seemed at the time that changing the gerund to reasoningmight do the trick, for reasoning is also practical as well as theoret-ical; it involves as much doing as thinking. It would have been bet-ter to have been explicit, speaking of styles of scientic thinking &doing in the European tradition. By the time he wrote the prefaceto his big book (Crombie, 1994, p. i-vii), Crombie was well awarethat the phenomena he was describing are a product of [human]nature as conscious embodied beings. This embodied creatureuses not just its mind but its body to think and to act in the worldin which it nds itself. There is also a lot more to be said for Crom-bies thinking, for, as he wrote in the rst paragraph, scienticthinking combines imagination and reasoning. Probably bits ofhis 1994 preface are a gentle reprimand to LT&R of 1982, and toits successor text of 1992 (with which Crombie was well ac-quainted before its publication).

Crombie offered a sensible template of modes of investigationin the sciences. We can establish in the classic scientic movementa taxonomy of six styles of scientic thinking, distinguished by

ophy of Science 43 (2012) 599609things, which are found in all languages, but objects bearing a def-inite role of sub- and super-ordination to other objects of the same

sort. Hypothetical modelling introduces non-observable theoreti-cal entities.

Geoffrey Lloyd sensibly preferred styles of inquiry in order to

I. Hacking / Studies in History and Philosophy of Science 43 (2012) 599609 601Crombie sometimes referred to his six as methods (1981, p.284) rather than styles (1994, vol. I, p. 83). Another available mon-iker is: genre of scientic inquiry or investigation. Often somethingmore casual may be preferable: ways of nding out in the sciences.Not only nding out that so and so, but also, nding how to.Finding out whats true, and nding out how to change things.The styles project no longer has any commitment to the wordstyle.

A difculty with the word style is that it has had such a variedhistory, most particularly in its adopted homeland, the history ofart. As Simon Schaffer (2010) reminds us, a typically rich essayby Carlo Ginzburg (2001) shows that in the arts, the word has oftenbeen invoked in the subtexts of conservative ideologies that manyof us nd suspicious and sometimes repugnant. User beware! Thelongest chronicling of the use of the word in a special science is thesurvey of mathematical style by Paolo Mancosu (2009). Some ofthe usages in his catalogue are very odd, but most seem prettyinnocent, and a few of the old usages contain real insights fortoday.

The 1992 title, Style for historians and philosophers, was amistake, for the paper addressed philosophy, not history. Histori-ans do, nevertheless, use the word. Thus in 2008, the focus of theannual meeting of the European Society for the History Sciencewas Styles of Thinking in Science and Technology (Hunger, Seebacher,& Holzer, 2009). Its prospectus begins with a bow to Crombie andstates that the time has come for a full development of his lead. Itpoints to diverse elds of important research: it is time to recon-sider this fascinating topical subject [styles of scientic thinking],in order to broaden earlier, Eurocentric approaches. Which philo-sophical, cultural, religious, political, economic inuences can beidentied that led to certain styles of thinking in science and tech-nology all over the world and that inuenced their further develop-ment? Cross-cultural inuences and interrelations are of specialinterest. How are such traditions of thinking transmitted to latergenerations, to other cultures? How are they modied in thecourse of history?

5. A rose by any other name. . .

Some would say that a skunk by any other name would smell asfoul. LT&R and subsequent work tried to patent the phrase, stylesof scientic reasoning, restricting it to items on Crombies list orsimilar. It had not been used previously in any specic context. Itseemed available to choose as a name, so why not lay claim toit? That was a foolish mistake. The phrase at once took off andwas used in all sorts of contexts that had nothing to do withLT&R or Crombies template. Quite rightly, too.

The phrase has now been applied to all sorts of things, startingmost inuentially with Arnold Davidsons Emergence of the Psy-chiatric Style of Reasoning (a subtitle to his early paper, Closingup the Corpses, and his general analysis Styles of Reasoning: Fromthe History of Art to the Epistemology of Science. (Both reprintedin Davidson, 2001.) Google directs one to many sites that speak ofDavidson and Hacking on styles of reasoning as if they were a unit.That is a misapprehension. Much as I admire Davidsons work, hetook my phrase in a direction totally different from what I in-tended.1 He and many others were right and I was wrong. Of coursethe phrase can be applied to a host of, well, styles of reasoning, and itwas stupid to try to patent it, and restrict it to members of a list.1 The subtitle of Davidsons book is Historical Epistemology and the Formation of Concepepistemology. For the record: I cannot recall ever thinking of the styles project as led unkeep the nomenclature different; that was for his breath-takingseries of cross-cultural studies of the sciences, for which referencesmay be found in Lloyd (2010). For one of many excellent uses of theoriginal phrase, we need go no further than the title of a book by acontributor to this issue, James Elwick (2007). His Styles of Reason-ing in the British Life Sciences: Shared Assumptions, 1820-1858 isabout a specic group of sciences, an insular band of practitioners,and a time-frame of 38 years. Of course it is about styles of reason-ing used by those workers in those years. Elwicks thesis, muchcondensed, is that despite vociferous disagreements among Britishnaturalists, biologists, and medical men, there were certain under-lying ways in which they approached their subject-matter: sharedstyles of reasoning.

6. NO necessary and sufcient conditions

It was hubris to try to patent styles of reasoning, but there wasalso an inexcusable error. Naming the class of items on Crombieslist tended to reify it. It suggested that the styles he listed had somedistinctive logical property that the philosopher might elucidate.Should there not be rough and ready necessary and sufcient con-ditions for being on Crombies list? No. His styles of scienticthinking & doing have no essence. That is not to say that the listis arbitrary, or that the idea behind it is vague. It is not even to im-ply that its members are bound together by family resemblances.

Crombie used the word in a purely descriptive way, like an earlytaxonomist noticing the birds and the bees. He said Look! These areseveral distinct genres of inquiry used in modern science, and theypretty well cover the waterfront. If we ask why they persist the an-swer is more likely to be ecological than logical or pragmatic. Wedo not use them because we have good reason to use them. Theyare what we use. They become our standards for good reason.(Anarcho-rationalism!)

Styles, genres, inquiry, and ways of nding out: all these wordscan be used to describe a great many more kinds of practices thanCrombies six. Occasionally, when I wish to be clear I am talkingjust about the items in his template, I shall use the ugly name,hereby patented: styles of scientic thinking & doing in the Europeantradition. Happily context is usually sufcient, and resort to adreadful convention is seldom needed.

7. Logic

Why isnt logic on the list? Surely thats reasoning if anythingis! The short answer is that logic is topic-neutral in a way thatstyles of thinking & doing are not. It has three branches, as setout by C. S. Peirce, namely deduction, induction, and what he calledabduction, or the method of hypothesis, more recently namedinference to the best explanation. Unlike the items of Crombieslist, these are used in any kind of conversation whatsoever. Theyare also prior to any science, although we have honed deductionin the mathematical style, and honed induction using probable rea-soning and statistical inference.

Present American undergraduate education implicitly accordswith this understanding. Courses variously called modes of rea-soning or critical thinking or symbolic logic are forced on everystudent of the arts and sciences, on the grounds that logic is a pre-requisite for clear thinking, independently of the subject matter.Sometimes the students are also taught to distinguish good frombad science; the bad is often, wrongly called pseudo-science.ts. That may have contributed to the association of the styles project with historicalder historical epistemology.

We may briey point to a further reection that must be devel-oped at length elsewhere. Mercier (2011) argues that arguing is a

We owe that wonderful canard, whig history, to Herbert Butter-eld. The most vicious whig historian in his bestiary was David

602 I. Hacking / Studies in History and Philosophy of Science 43 (2012) 599609universal human practice. Mercier and Sperber (2011) contendthat it is not for nding out the truth or deciding on the best courseof action. Arguing is for maintaining ones own opinions againstthose of others. This sounds implausible to all of us brought upon logic since Aristotle and the syllogism. But if we had been read-ing his Topics (about dialectic and arguing back and forth withequals) and Rhetoric (about presenting an argument to an audi-ence), Mercier and Sperber might have seemed less iconoclastic.(They themselves were unaware that Aristotle had been there be-fore them.) They maintain further that their account of argumentexplains apparently innate human inadequacy in logical thinking,illustrated by the group of phenomena made quantitative by cog-nitive psychologists such as Tversky and Kahneman. What is inef-cient at extracting truth from data is efcient for convincing otherpeople. They go so far as to suggest that the practice of arguingmay have had a good deal to do with the emergence of humanspeech. Thus arguing, on their analysis, is universal, ancient, atten-tive to persuasion rather than truth, and largely independent of sci-entic reason.

Why do we have such a different impression of logic? Perhapswhat happened was this. Arguing had been going on forever, wher-ever talkative people gathered. Aristotle wrote the rst textbooksabout how to argue (or gave classes that became textbooks). Laterhe invented the idea of logical form, which he imposed on simplearguments such as the most important structure he devised, thesyllogism. This was happening around the same place and timewhere demonstrative proof had been discovered. But logic andmathematics pursued different careers until the 19th century,when the likes of Boole, Frege, and Peirce began to absorb logic intomathematics. This sketch may be a prelude to a deeper under-standing of the difference between scientic reason and logic.

In parenthesis: we take for granted that much of the actual dis-course among scientists consist of arguing in the sense of Mercierand Sperber: trying to inuence the opinions of colleagues, rivalsand patrons. That is what Aristotle called dialectic and rhetoric,two words that have been debased since his time.

8. Whig history

Crombies template has an initial virtue. It does not suffer frommetaphysical numerology. It is not monism (one), dualism (two),triads (Kant and Peirce) or wafe (many). Just plain old boringsix. Admittedly that is an instance of The Magical Number Seven,Plus or Minus Two, George Millers (1956) claim about the limits ofour ability to process information. (None the worse for that!) AndCrombie did surrender to numerology, recasting his six as twogroups of three.

The template is, nonetheless, an unsurprising description of dis-tinct genres of inquiry deployed in all the sciences, though in vary-ing proportions for each special science. It is often emphasized thatCrombie was a Roman Catholic by conversion, and attached fargreater weight to mediaeval Christian (but not Islamic) contribu-tions than they deserve. Much more importantly, he was a whighistorian, forming a list of basic types of scientic investigationin current use, and looking into the historical trajectory that endedus up here and now.

What are the principles of individuation for Crombies sixstyles? We start from now, with six rather visibly different meth-ods, and work back, tracing lines of liation with past practices.2 From a letter by Einstein to J. S. Switzer, 23 April 1953; Einstein Archive 61-381.00. I3 Critique of Pure Reason B x-xii. The emphases are Kants. He invented the very idea

paragraphs in the second edition (1787). They speak several times of revolution, and areHume, the patron saint of analytic philosophers. Perhaps philoso-phers are, by nature of their interests, whiggish.

One could cloak the styles project in the mantle of a recentlytrendy phrase used for a short time by Michel Foucault, historyof the present. That would be pretentious: the shoe does t, butit is for dancing only. A self-conscious use of the past to reecton the present has all sorts of dangers, but philosophers are inthe business of living dangerously. Crombie was right to say, in ef-fect, Look! Here are these six. So what six was he looking at? Threeof them are tried and true, three of them are true but not so oftentried.

9. The three obvious candidates for the template

Every once in a while Einstein said something perfectly obviousand on which everyone was already agreed, but which was stillworth saying.

Development of Western science is based on two great achieve-ments: the invention of the formal logical system (in Euclideangeometry) by the Greek philosophers, and the discovery of thepossibility to nd out causal relationships by systematic exper-iment (during the Renaissance). In my opinion one has not to beastonished that the Chinese sages have not made those steps.The astonishing thing is that those discoveries were made atall.2

Well, actually Chinese scholars did make many steps towardsthese achievements, but Einstein was a man of his time. And byimplication I have just distinguished logic from geometry. Theimportant insight is that these inventions and discoveries, as Ein-stein rightly calls them, were not discoveries of facts or technolo-gies, but discoveries of how to nd out. Compare Kant:

In the earliest times to which the history of reason extends,mathematics, among that wonderful people, the Greeks, hadalready entered upon the sure path of science. [ . . . ] the trans-formation must have been due to a revolution [ . . . ].

Natural science was very much longer in entering upon thehighway of science. [ . . . ] In this case also the discovery can beexplained as being the sudden outcome of an intellectualrevolution.3

These words are from the preface to the second edition of theCritique of Pure Reason. Between 1781 and 1787, Immanuel Kant,the Captain of Team Reason, noticed that reason has a history.

Kants examples of the second revolution make plain that he isreferring to the same discovery as Einstein, namely systematicexperimentation: When Galileo rolled balls of a weight chosenby himself down an inclined plane, or when Torricelli made theair bear a weight that he had previously thought to be equal to thatof a known column of water . . . Note that both examples, althoughmotivated by speculation, are described as well thought out exper-imental exploration, and not as theoretical science.

Kant and Einstein used different words. One said achievementand astonishing, where the other said sudden outcome and rev-olution. They describe two signal discoveries differently, but theyare pointing at the same two local events, one in ancient Greece,and the other late in the European renaissance or early modernperiod. Both men saw clearly that these two events marked radicalowe the quotation to Rasmus Winther.of revolution in science (Cohen, 1985). I most strongly urge reading the entire fewof great interest for other reasons too.

tool of inquiry.These images of mutations in thought and practice are both

ilosright and wrong. The discovery that we can make demonstrativeproofs from postulates was not an immaculate conception, but acontinuation of Mesopotamian and North African practice. On theother hand, there was a sharp break in the development of math-ematical reasoning, the discovery of the possibility of demonstra-tive proof. In the case of mathematics, A relatively large numberof interesting results would have been discovered practicallysimultaneously (Netz 1999, p. 273). Netz suggests a period of atmost eighty years.

We have no need to dismiss the Babylonians, Egyptians andothers who taught mathematics to the Greeks, in order to see thata revolution in reason was wrought. This is a crystallization ofpractices begun much earlier. The metaphor is far from perfect,but it allows us to acknowledge sharp breaks within what, in ret-rospect, is the long haul from the dim realization of a new wayto carry on, to the present well-developed mathematical style ofthinking & doing.

10. The laboratory

The styles project does not engage in historical research but isdelighted by new historiographical ideas that it can exploit. Netz(1999) provides one such: the rst analysis of what did happento mathematics and proof during a brief period of time.

Thanks to Shapin and Schaffer (1985) it is now possible to local-ize another crystallization of practices, this time within the tradi-tion of experimental exploration. Boyle and the air pump, andmore generally the laboratory, represent the second revolution ofwhich Kant spoke. Kant himself signalled Torricelli and Galileo(Galileo the experimenter). He recognized that Galileo asked spe-cic questions, but did not emphasize that Galileo built specialapparatus to elicit the phenomena. Around 1987 Stillman Drake,the great advocate of Galileo as experimenter, reconstructed Gali-leos gigantic inclined plane from scratch in Toronto, and more orless duplicated his results. I once wrongly suggested that we addthe laboratory style to Crombies list, as a style that builds appa-ratus in order to elicit or create new phenomena, rather than byexploring and measuring what is already there to be found. The ad-vent of the laboratory is a radical eruption, but Occams razorinnovations in human life. Both saw that we had to nd out how tond out.

These two achievements are what Crombie picked for his rsttwo styles, which I label mathematics and experimental explora-tion. He called his third style hypothetical modelling. Kant (andmore interestingly Einstein, the greatest of theoreticians) did not,in the passages quoted, notice this as a different way of engagingin scientic research. Husserl did. Galileo is unique, in that hehas been taken as an emblem of experimental exploration and ofhypothetical modelling. Since these two have since been run to-gether as constituting the scientic method, Galileos double dutyis not so often mentioned.

Kant rightly attended to the legend of Galileo the experimenter.Husserl, moved by the more modern spirit of Alexandre Koyr,took the great achievement of Galileo to be the mathematizationof the universe. Crombie showed amply that hypothetical model-ling long predates Galileo, even if he was misguided in putting somuch emphasis on mediaeval sources. Galileos role model wasArchimedes, not the scholastic dabblers. The relevant fact is thatat the time of Galileo, and importantly through the mans ownwork and triumphs, mathematical modelling became a paramount

I. Hacking / Studies in History and Phmoves us to regard it as a crystallization within Crombies secondstyle, rather than as a new style.Leviathan and the Air-Pump (Shapin and Schaffer, 1985) and TheShaping of Deduction in Greek Mathematics (Netz) are ground-breaking analyses of crystallizations in two fundamental genresof inquiry. I introduced Bruno Latour to Netzs book, which ledhim to write,

This is, without contest, the most important book of sciencestudies to appear since Shapin and Schaffers Leviathan and theAir-Pump (Latour, 2008. p. 441).

Latour and I agree on the centrality of these two books to theunderstanding of the sciences, although my reasons are differentfrom, and additional to, his. It is a feature of great books that theycan serve many ends, and be read in many ways.

This is not to imply that Latour, Shapin or Schaffer would in anyway support a use of their work for the styles project (nor any ofthe other persons named earlier, such as Feyerabend or Foucault).Schaffer himself (2010) has some characteristically elegant (andwry) criticisms of it. Likewise Kant, Husserl and Einstein are notauthority gures who legitimate the project. The point is only thatCrombies rst three styles of scientic thinking match with a greatdeal more established analysis, some old, some quite recent. Thatdoes not make it right, but it does make it familiar.

11. Mutation and continuity

Crombies template begins with the obvious three styles, andmoves on to the less prestigious. There is classication, one aspectof which crystallizes at the time that Aristotle was composing hisnatural histories. That evolved into taxonomy, and crystallizesaround 1735 when Linnaeus stepped off the boat in Amsterdamcarrying some astonishing folio pages. Soon thereafter the classi-cation of living things became increasingly hierarchical, with taxaordered by subordination to higher taxa. Probability crystallizesin the time of Pascal. Then there is historico-genetic explanation,whose triumph is Darwins explanation of the species by naturalselection.

The label historico-genetic explanation, used as shorthand torefer to the sixth style, is unfamiliar. It is not just explanation,but explanation with a view to nding outnding out how wegot to here. Thus it employs one branch of logic, namely abductionor inference to the best explanation, to an unusual extent. It startswith assumptions about how things stand, in some domain ofinterest. (Earth is populated by pretty distinct kinds of plants, ani-mals and other living things, which propagate in their kind.) Anoutstanding explanation is devised, of how things got to be thatway. (Darwins one long argument.) We infer from the power ofthe explanation, and its superiority in detail to any other availablecandidates, that it tells how things were. This genre of reasoningbegan long before what we call the sciences. There are the myriadorigin myths of which the Hebrew Genesis is only one example. Itincludes the philosophers such as Leibniz and Kant on the earlyEarth. It includes the alignment of the planets, and perhaps it cul-minates when it is merged with (mathematized) hypotheticalmodelling in the Big Bang. This reminds us that the specic trajec-tory of each method of inquiry is its own, and will not much resem-ble that of any other method.

It is striking that each of these several ways of nding out isassociated with a legendary gure, a name, a hero in history. His-tory can no longer brook heroes, but philosophy ploughs the soilof common knowledge. Kant set the right tone when he spoke ofThales or some other. We are not concerned with the biographyof a legendary Thales or the historical Pascal, in person. Commonwisdom has chosen to erect a monumental gure at each of these

ophy of Science 43 (2012) 599609 603eruptions in reasoning. Crombie does not identify Galileo witheither experimental exploration and the laboratory, or with hypo-

ilosthetical modelling. I identify him with both. That may be becauseCrombie is a historian who has specialized in Galileo and looks atthe whole man and his work. The philosopher singles out two leg-ends of Galileo, one captured by Kant (and Stillman Drake), theother captured by Koyr and Husserl.

All this talk of legends seems like mere happenstance to brushaside. I cannot justify it. It looks like an accidental feature of away of telling a story. Yet JeremyWanderer argues in his paper be-low that at least in the case of mathematics, there is a seriousphilosophical lesson to be gleaned from this practice, one that isconnected with normativity.

12. Ludwik Fleck

Ludwik Flecks theory of the Denkstil and the Denkkollectiv wasthe rst use of the idea of a style of scientic thinking. Fleck hasbeen picked up as a pioneer, perhaps a founding father, of socialstudies of science. Some say he was a deeper thinker than T. S.Kuhn, who himself acknowledged his debt to the man. The stylesproject would have been richer had it invoked Fleck thirty yearsago. Today he can be used as a corrective to, a prophylactic against,the legends just invoked.

Those who read his book in English translation know its title asGenesis and Development of a Scientic Fact (Fleck, 1979). His Ger-man subtitle was mislaid along the way: Introduction to the Theoryof the Thought-Style and the Thought-Collective (Fleck, 1935). Thetwo words, Kollectiv and Stil, were put to protean uses by Germanintellectuals in the early twentieth century. Art history, of course.In political economy and sociology, for sure. Also for example byRichard von Mises (1928) in his analysis of the uses of probabilityin statisticsand in 1931, in theoretical physics. These notionswere all over the place in those days, including some despicableones (jdishe Denkstil). So beware!

As Flecks subtitle makes plain, Thought-Style and Thought-Col-lective go hand in hand. A Thought-Collective is a small network ofinvestigators who address a family of problems that they under-stand in much the same way, and which they attack using a groupof mutually intelligible methods. Flecks Thought-Styles were con-stituted by the types of questions asked, the range of possible an-swers that was envisaged, the methods which were useful, and thebackground information taken for granted. A Thought-Collectivewas a social unit identied by education, training, interests, andmutual communication. Thought-Collectives are local, cohesive,but relatively short-lived, for they tend to dissipate as questionsbecome answered or problems prove to be intractable. Peoplemove on, and out of the collective.

We can extend Fleck and think of nested (also, interlocking)Thought-Collectives. Elwicks study of British life sciences 1820-1858 (5 above) can be parsed in those terms. A large Thought-Col-lective with shared assumptions spanned most of the workers hestudied, while the competitions he describes were between rivalCollectives within the British nest.

Now to the legends. Kant really did have the picture of a lightbulb going on over the head of Thales or some other. It is neverone person. It is always some small group, and there always hasto be a larger uptake in order for any new way of thinking to sta-bilize. It is inviting to proceed using Flecks words: a smallThought-Collective emerges around a tremblingly new Thought-Style. We can use Flecks words without the implication that it isall in the head, thought. The reason that Fleck has been so attrac-tive to sociologists of scientic knowledge is that they disregardthe mental meaning of thought and attend to the social relationsbetween the actual protagonists, and their material experiments.

604 I. Hacking / Studies in History and PhFleck brilliantly describes both in his study of syphilis. On anotheroccasion, a Fleck-like picture may be offered for each of the crystal-lizations already mentioned. In Leviathan and the Air-Pump, thelarge Thought-Collective is none other than the Royal Society ofLondon, within which Boyles team was nested. Hobbes wasnt,and he tries to maintain an older Thought-Style.

13. Crystallization

The metaphor of crystallization is handy. Many readers of theEmergence of Probability (Hacking, 1975) have tried to undo its pre-mise, that, to put it crudely, there was no probability before 1650or so. A few of these helpful critics are mentioned in Hacking(2006). There is a long history of various kinds of probable reason-ingcharted globally by Crombie himself, and locally by meticu-lous scholars (e.g. Maclean, 2002) in greater detail. There was,nevertheless, a radical change in the very feel of chance and of evi-dence that took place during the second half of the 17th century. Itwas a crystallization of ideas that had been inchoate for centuries,and which precipitated at that time to create the conceptions ofprobability that have come to dominate the modern world. Thatwas not the end of the story (and here the metaphor of crystalliza-tion is defective). The Taming of Chance (Hacking, 1990) expoundssome large scale socio-political events that helped bring us up towhat we now call scratch.

The same metaphor of crystallization suits the discovery ofdemonstrative proof in the Eastern Mediterranean. There was noimmaculate conception, for sure, but something radical did hap-pen, a crystallization of old practices into a new way of ndingout, namely by proving. This does not imply (as the metaphor ofcrystallization would do, taken strictly) that mathematics becamea rigid crystal. It is far from clear what makes mathematics math-ematics (Hacking, 2010a), but it is certainly a long series of contin-gent events, which are still going on apace with, for example, theadvent of computer-generated proof. There is much to be said forthe iconoclastic opinion of Doron Zeilberger (2010): Our mathe-matics is an accidental outcome of the random walk of history,and would have been very different with a different historical nar-rative. (Original italics.)

The metaphor of crystallization also ts the radical changewhen hypothetical modelling was mathematized by Galileo andhis peers. Likewise, the transition from experimental explorationto the systematic creation of phenomena in the laboratory, at thetime of Galileo and Boyle. This was such a radical transition thatHacking (1992) unwisely proposed that it was a new style of rea-soning, a merging of experimental exploration and hypotheticalmodelling.

It is a strong temptation. Thus Bernadette Bensaude-Vincent(2009a, p. 18; cf. 2009b) proceeds in that direction, suggesting thatwe should subdivide N2 in Crombies list in order to give morevisibility to a specic style of thinking induced by chemical labora-tory practices. In my opinion, it is better not to multiply six be-yond necessity, and instead to see the invention of the laboratoryas making experimental exploration more systematic, to useKants word. It is also to be noticed that the chemical laboratoryis different from, and older than, the physical laboratory.

Mergers are often more interesting than splits. For example, theway in which historico-genetic reasoning in cosmology and life sci-ence is giving way to hypothetical modelling and experimentalexploration in accounting for the origin of things. And althoughexperiment has a life of its own, laboratory work without hypo-thetical modelling would be as worthless as the frantic collectingof Francis Bacons ant in his parable of ant, bee, and spider (Apho-rism XCV of theMagna Instauratio). And hypotheses without exper-iment are like the spider. Scholars no longer appear to speak of the

ophy of Science 43 (2012) 599609scientic method, but until quite recently it denoted the bee, whocombines the talents of ant and spider.

external canon of truth independent of itself.It will be protested here: but the justication is pragmatic.

ilosThese styles of reasoning work! That is the standard to which theyanswer. There is no external canon, of the sort demanded by corre-spondence theories of truth. But there are still standards, prag-matic ones.

Pragmatism is indeed a helpful rst step away from foundation-alism. But, in the constant quest for the nal stop on the journey, itpulls up at that Victorian value shared by Marxist, Protestant, Cap-italist and William James: the eternal value of Work.

Something works if it has results that were intended, or are toour liking. Technoscience has indeed enabled us to change theworld, mostly to our liking. The maxim, that nothing succeeds likesuccess, is a deeper saying than is usually understood. For successhelps determine what will count as success. Success has a lot to dowith future success because it helps characterize what in the fu-ture will count as success. We continue to change the world mostlyto our present liking partly because what we like has been so pro-foundly affected by things we have grown to like and which areproducts of the sciences. The styles ourish in a complex web ofinteractions whose evolution they help determine. That is whythe ecological metaphor already mentioned in 2 and 7 above,to be developed further in 20, is so inevitable.

15. Truthfulness

Bernard Williams Truth and Truthfulness (2002) is a work ofprofound originality on many fronts. Only one of its many facetswill be used here. It suggests a way to explicate the autonomy ofCrombies styles, in a way that is aligned to discussions of truthby analytical philosophers. That will make the notion more acces-sible to one class of readers, and less accessible to another. So be it.

Williams asserted that the concept of truth has no history. Theconcept of truth itselfthat is to say, the quite basic role that truthplays in relation to language, meaning and beliefis not culturallyvarious, but always and everywhere the same (p. 61). Most ana-lytic philosophers would agree. Many other serious thinkers, forexample those rightly fascinated by Steven Shapins (1994) A SocialHistory of Truth, would wholeheartedly disagree. I believe Williamsmight have thought the difference was more in words than con-tent. He might have said of Shapin what he said of Foucault, thatmuch of such work addresses epistemological issues, of what atdifferent times counts as establishing truth in different elds (Wil-14. The autonomy of Crombies styles

A central idea of LT&R was that scientic styles of thinking &doing are not good because they nd out the truth. They have be-come part of our standards for what it is, to nd out the truth. Theyestablish criteria of truthfulness.

LT&R proposed that Crombies styles are self-authenticating.One point of the expression has long been trite. Epistemology usedto search for foundations. Peirce and then Popper, and then a hostof writers, have emphasized that knowledge has no foundations.But the quest for foundations goes on. The task of the logician,one might think, is to nd a foundation for reason. Self-authenti-cating might serve as an antidote. Scientic reason, as manifestedin Crombies six genres of inquiry, has no foundation. The styles arehow we reason in the sciences.

To say that these styles of thinking & doing are self-authenticat-ing is to say that they are autonomous: they do not answer to someother, higher, or deeper, standard of truth and reason than theirown. To repeat: No foundation. The style does not answer to some

I. Hacking / Studies in History and Phliams 2002, p. 300, n. 31). He denied that truth has a history, butsaid that criteria for telling the truth in a given domain change overthe course of time. He expressed this by saying that truthfulness hasa history while truth does not.

The styles project can followWilliams and say that truth has nohistory, while truthfulnessthe possibility of telling the truthabout a specic topicdoes have a history. That is the idiom of ana-lytic philosophy. One can recast the same thoughts using an alter-native idiom. Thus for example where Shapin writes very clearlyand naturally about a social history of truth, Williams can say thatthe criteria and practices of truth-telling have a remarkable socialhistory: indeed he tells some of that himself in his inimitable way.

Williams did not nd a distinction between truth and truthful-ness; he made one. Contrary to the common self-understanding ofanalytic philosophers, most distinctions in analytic philosophy aremade, not found. That is, they do not exist as facts in a pre-existingconceptual scheme which careful observation reveals. Here we canadapt the familiar Leibnizian image of the sculptor and his block ofmarble. No one seriously imagines that only one sculpture couldemerge from a raw lump. What the analytic philosopher does is at-tend to one vein in the conceptual stone that is useful for a certainpurpose, but there may be other veins in the marble that yield adifferent carving. Just as the sculpture is made by the sculptor, soa distinction is made by the philosopher. (Once again ordinary lan-guagewe say, we make distinctionshits the right nail on thehead.)

Williams took two ordinary words, truth and truthfulness.One, together with its core cognate, the adjective true, is in useall the time. The other, truthfulness is seldom used. He wanteda word connected with truth, but which reects the way in whichthe truth in various domains can come into being. LT&R expressedvery much the same idea by saying that with the emergence of anew style of thinking & doing, new sentences came up for grabsas true or false. It would have been more prudent to add, or aregrabbed in new ways.

This is connected with a related theme in LT&R. It urged thatQuines notion of a conceptual scheme, which he explained as aset of sentences held for true, should be replaced by a set of sen-tences up for grabs as true or false. Thus emergence of a new styleopens new spaces of possibilitiesnot an idea on which Quinewould have looked with favour!

16. Shifts in conceptions of how to tell the truth

What use did Williams make of his new distinction? He claimedthat Thucydides effected a fundamental change in the practice ofhistory-writing. A new criterion for telling the truth about the pastentered the eld. Every event must be presented as occurring be-fore, after, or at the same time as every other event. Many woulddescribe this as a conceptual truth, but it is one that entered oursystem of historical thought at a specic time in the West (andat a slightly different time in China). It was a new criterion fortruthfulness about the past.

Williams fundamental assertion is that there was, most basi-cally, a shift in conceptions of what it is to tell the truth aboutthe past (p. 154). The styles project latches on to the logical formof this thesis, as expressed by the schema ():

() There was a shift in conceptions of what it is to tell the truthabout X.

That sounds as if X is a given, X = the past, or, in the case of theemergence of authenticity, X = the self, the past and the self beingtimeless entities. Not so. New ways to tell the truth about X changeour conceptions of X itself. Williams talks of a shift from a localto an objective view of the past (p. 163). Here are some more

ophy of Science 43 (2012) 599609 605snippets from what he says about history (pp. 170-1): This signif-icant change that took place in the fth century B. C.; It was the

invention in the West of historical time. It did introduce an in-crease in explanatory power. It does not, however, mean that

ontological, appear to be of three sorts. One type is sceptical. Does

606 I. Hacking / Studies in History and Philosophy of Science 43 (2012) 599609those who operate in the new style, who have the objective con-ception of time, are more rational or again better informed thanthe others. Their predecessors were not confused; they did not be-lieve something contrary to the later historians. Most importantly,The invention of historical time was an intellectual advance, butnot every intellectual advance consists of refuting error or uncov-ering confusion.

The schema () can be expanded:This signicant change took place in the Y century, in connec-

tion with an emblematic gure Z.

In history, X = the past, Y = the fth century BC, and Z = Thucyd-ides. For authenticity, we have X = the self, Y = the eighteenth cen-tury, and Z = Diderot and Rousseau. Heroes in history! Legendarygures again.

Note how well the metaphor of crystallization ts Williamstwo cases. People had been writing histories for a goodly time be-fore Thucydides, and some notion of authenticity was around longbefore Diderot. But it is widely agreed in both these cases thatsomething signicant in Western practice occurred around thetwo periods singled out byWilliams analysis. In each case we havea crystallization within previous ways of going on. Whether Wil-liams was right about history or authenticity, our concern is thegeneral schema of a shift in conceptions of what it is to tell thetruth in some domain of inquiry.

If Williams is right, Thucydides is a legendary trailblazer, anicon around whom crystallized new ways of telling the truth aboutthe past. There is an inviting parallel with Thales or some other.There was a shift in conceptions of what it is to tell the truth aboutgeometry and of mathematics more generally. Proof became thegold standard for the truth of mathematical propositions. This sig-nicant change took place in the sixth century BC, and its emblem-atic gure is Thales. Thats Kants story. After reading Netz wemight prefer to replace the legendary Thales by another gure,and move the date down a bit.

We are in effect asserting that there are distinct criteria oftruthfulness in different types of domain. This well ts the verica-tion principle (shades of Ayer, 1936 with which we began in 2).But it will sound repugnant to much modern analytic theorizingabout truth. (I recall Donald Davidson thinking the project wasamusingly ingenious but ludicrous.) Yet it has no problem withTarskis celebrated schema T, held to be the sine qua non of truth.It even gibes well with Crispin Wrights (2003) pluralism, whichholds that one can be a realist about mathematics (platonism)and an anti-realist about history, or vice versa. Wright developedhis pluralism from Michael Dummetts notion of bivalence, deduc-ing that truth conditions works out differently in different elds ofdiscourse.

17. Ontological debates

There are innumerable questions about what exists, from theHiggs boson, to a slow leak in my bicycle tire. We know how totry to answer them, and in the rst case have been willing to spenda fortune from national treasuries trying to do so.

Philosophical questions about existence are different in kind, fordebate is interminable. New and sometimes fascinating thingskeep on being said, but impasses seem permanent. Checkable factsseem to have no bearing. Such questions, which will be called4 Hacking (1983) took scientic realism seriously when it presented an experimental argone. A remark on page 2 is seldom noticed: Disputes about both reason and reality have lonit. I continue to doubt it.the external world exist? Are there other minds? These questionsare asked by children about the age of six or seven, with little orno prompting. They may be called pre-scholastic.

A scholastic question arose in logic. Do universals exist, or onlytheir instances? The positive answer was long called realism. In1492 Spanish scholars named the opposite doctrine nominalism.This usage of the word realism is no longer in fashion among ana-lytic philosophers, having been replaced by realism as bivalence, asin Dummetts school just mentioned.

Here we are concerned only with a third sort of ontologicalquestion, the one that arises in the sciences, and which preoccupiesus here. The most longstanding example is about the abstract ob-jects of mathematics, such as numbers, groups, topological spaces,or, in the rst instance, shapes such as the circle, the sphere, andthe polyhedron. Do such objects exist? The afrmative answer iscalled mathematical realism or platonism. (This species of plato-nism is best written with a small p.) Do non-observable theoret-ical entities exist? The afrmative answer is called scienticrealism.

The styles project may cast the third type of ontological debatein a new light. It suggests that the third type is a by-product ofstyles of reasoning. This may be therapeutic, but for those whowant yes/no resolutions to each question, debate is intermina-bleone might almost say, incurable.

18. The by-product account of ontological debate

In 4 above, styles of scientic thinking and doing were said tobe characterized by their objects and their methods of reasoning.Early on, the styles project maintained that each style of scienticthinking & doing introduces a new class of objects. Hence it is plau-sible to suggest that ontological debates of the third type are by-products of the introduction of a class of objects by a distinct styleof scientic thinking & doing. But what is this introduction?

This does not mean that objects of the class did not exist beforethere was a way to investigate them. That is nonsense. Each newstyle of thinking & doing introduced a new class of objects into dis-course. We may bypass an explication of this sense of introduc-tion and say only that ontological debates of the third type areby-products of the emergence of a style of scientic thinking &doing. But it is important to avoid brief generalizations. Every stylehas its own personality: the way that arguments over the existenceof species or of the higher taxa are engaged, are quite differentfrom arguments about platonism.

In taxonomy, the reality of the higher taxa, or even of the spe-cies themselves, continues to be contested. Philosophical thinkingabout probabilities is littered with lesser debates about the realityof statistical entities. In at least these cases we may offer a diagno-sis of the ontological disputes. It does not make them go away:there will always be platonists and anti-platonists. But for thosewho have difculty taking the debates seriously, a diagnosis maybe helpful.4 The ontological debates are by-products of the waysin which styles or reasoning introduce into discourse new classesof objects.

19. Cognitive history

Let us pass from the deserts of ontology where nothing our-ishes but controversy, to pastures full of new growth. Netz subti-tled his book about Greek deduction A Study in Cognitive History.ument for realism about theoretical entitiesas the best argument, not as a conclusiveg polarized philosophers of science. [ . . . ] Is either kind of question important? I doubt

I take him to mean an attempt to understand how an organism rather than an English term, modelled on the work of the great

I. Hacking / Studies in History and Philosophy of Science 43 (2012) 599609 607with certain cognitive capacities developed sophisticated tech-niques of demonstrative proof in a corner of the Mediterranean2400 years ago. In his own words, proper cognitive history refersexplicitly to the biologically cognitive facts out of which the partic-ular bit of history is made, and provides an account for how suchskills got to play out and be transformed through history.5

Netz is frank about the current state of what he named cogni-tive history. When a student wrote asking him what he meant bythe term, Netz replied by quoting Ghandi. When Ghandi was askedwhat he thought about Western civilization, he replied that hethought that it would be a good idea. Netz continued by saying thatthats what he and I think about cognitive history: it would be agood idea.6

In the case of mathematics, a cognitive history can draw onmany recent results and proposals that can be identied in neuro-science, cognitive science, developmental psychology, anthropol-ogy, and history (including but not exclusively the history andprehistory of the sciences). There are whole new elds of great rel-evance, such as captured by a subtitle, Archaeology Meets Neurosci-ence (Renfrew, Frith, & Malafouris, 2009), going back to TheArchaeology of Mind (Renfrew, 1982). But we have not yet begunto ght. What we have, even in the most favoured style of scienticthinking & doing, namely mathematics, are just islands of cognitivehistoryin a sea of ignorance (Hacking, 2010b). As Netz said, cog-nitive history would be a good idea.

How would cognitive history play out with other genres of in-quiry? Much of Scott Atrans Cognitive Foundations of Natural His-tory (1990) can be read as a cognitive history of the taxonomicstyle. In the beginning is an innate module, which enables humansnot only to recognize plants and animals and other human-sizedliving things, but also leads them to a three-level taxonomic struc-ture. This is the ground upon which natural history travels through(but surely not beginning with) its formulation in the time of Aris-totle. It thus proceeds up to what Atran calls the scientic break-away, which culminates in the crystallization that I call Linnaeus,though others might prefer a different legend. This is a promissorynote, to be led under 23, To do.

20. Ecological history

The characterization of cognitive history in 19 was elliptic. Fillin the ellipsis. It is the study of how an organism with certain cog-nitive capacities, on a planet like this, developed (etc.). Hence it is afragment of ecological history.

Netz points to Alfred Crosbys work such as Ecological Imperial-ism: The Biological Expansion of Europe, 900-1900 (Crosby, 1986).That is the story of how organismsmen and womenwith certaincapacities that were useful in a small corner of the planet, wereable to transport their skills and modes of living, and adapt themto what they found elsewhere, thereby transforming the worldsthey found. They took with them organisms with which theycohabited, such as grapes, horses, and their notorious germs. Theirpractice of naming was exactly right: New Amsterdam, New Eng-land, Nouvelle France, Nova Scotia, or the Virreinato de NuevaEspaa. They transformed an alien habitat into a new England ora new Spain, and hence were able to prosper there and to subdueall that they found. Ecological imperialism: one ecology supplantsall the others.

Ecological history returns us to the long haul of Crombiesunfashionable practice of the history of science. He began to de-scribe himself as doing historical anthropology. That is a French5 Quoted by permission from an email of 26 January, 2010.6 Paraphrased by permission from an email of 10 February, 2010.classical scholar Jean-Pierre Vernant (1914-2007). In France, ithas become a sub-discipline of historical studies, where numerousschools and institutes are so named. Hence it is a term not to betaken lightly and I shall not do so. Otherwise I regard all these dis-ciplinary appellations as throwaway labels. Often on rst sightthey produce a sharp cry of recognition. Take the Archaeology ofMind just mentioned. It is the study of cognitive development ofthe human mind by reection on the evolution of artefacts. Weare to think not only about how humans made the artefacts, asin traditional archaeology, but also what the artefacts, once inuse, did to the human mind. When the labels make us stop andthink like this, that is a good thing. But later they tend to becomeslogans and should be put away. It is usually unwise to embed han-dles handy for a moment into the architecture of the humansciences.

There is no doubt that the styles project is anthropological incharacter. It is also ecological, for it is not just about what usedto be called Man, but about what used to be called Man and hisplace in Nature. Styles of scientic thinking & doing in the Euro-pean tradition are rooted in human biology and cognitive capaci-ties. Each emerges in a tiny locale, and even then involves only avery few of the people who live nearby. The styles turn out to havehad unparalleled effects on life on Earth. The study of these stylescan thus be led as a case of ecological imperialism. With animportant difference: In the end the Europeans in the Europeantradition do not matter, and will even cease to exist as an identi-able group. The styles of scientic reasoning do matter, and willcontinue developing long after Europe is just a relatively smallland-mass.

21. On the cumulative character of styles

In the whig history used by the styles project, styles of thinking& doing in the European tradition are cumulative. This is a virtualnecessity, for we dene them retrospectively, in terms of how wegot to here. But there is far more to accumulation than that. It ishinted at by phrases such as ecological history. The styles areadapted to their environment, but like any creature they alsochange the environment to their advantage. Latours riff on Archi-medes is perfect. Give me a laboratory and I shall move the world.

LT&R offered Paracelsus and the Doctrine of Similitudes as astyle of reasoning that we can scarcely comprehend in all its rich-ness and what we take to be absurdity. It is no longer with us, ex-cept in pale and ignorant shadows that pass themselves off ashomeopathic medicine. The pragmatist in all of us wants to saythat the scientic styles persist because they workand Simili-tudes did not. But Paracelsian medicine did not die because it didnot cure people. A commonplace nowadays: doctors never curedpeople until late in the 19th century. We do not well understandthe switch from (to use one possible description of what hap-pened) what Foucault called the pistme of the Renaissance, tothat of the era of Representation and what he called the ClassicalPeriod or what others call Early Modern Europe. But it certainlywas not because something did not work.

But yes, the genres of inquiry central to the sciences do work.But work for what? In part, for purposes of their own devising.Success, as was said in 14, helps direct what in the future willcount as success. In our case the effect is heightened, because suc-cess changes the world so that success of that kind is easier toachieve. This returns us to self-authentication. The styles in ourlist do not answer to any criteria of truthfulness other than their

own. They are not chosen because they work. They help deter- Barry Allen (1993) uses what he calls demonology as a sort of

608 I. Hacking / Studies in History and Philosophy of Science 43 (2012) 599609mine what counts as working.But let us not continue to be so obsessed with that notion of

work, which so captured William James, or even survival, whichso captured Charles Darwin. There is also play, which is somethingthat the survivors do in the world they are making, and in order tokeep themselves sane.

22. Work and play

For all its ultimate horrors, Europe in the 1930s produced a lotof good ideas of a very general kind, some of which long lay fallow.One is Flecks Thought-collective/Thought-style, published 1935,but activated only much more recently. Johan Huizingas Homo Lu-dens (1949)7, dating from 1934, is still fallow. It is not about the roleof play in culture, but about culture as in part constituted by play.

One of the reasons that the items in Crombies listlike so manyother communal phenomenahave been taken up over and overagain is their playfulness. People practice those genres of inquirynot just to nd out more about the world, or how to change it toour liking, but also for fun. And here I mean good clean simplefun for its own sake, childs play. Some cynics ridicule science asa game, but I do not mean anything highbrow, I mean fun.

Once again Reviel Netz is helpful. In Ludic Proof (2009) he arguesthat Archimedes, the greatest mathematician of the ancient world,made playful competition an integral part of his mathematical cor-respondence around the Mediterranean. That said, play could stillbe thought of as an element in proofwhich nobody would deny.Following Huizinga, we may suggest that play is not only an enjoy-able aspect of some proofs, but also is integral to the practice ofproving, proof-following, and proof-seeking. Not just in the timesof ludic proof, but right now.

Huizinga concluded his book with an aphorism: civilization is,in its earliest phases, played. It does not come from play like a babedetaching itself from the womb: it arises in and as play, and neverleaves it. Could we conjecture that proof was, in its earliest in-stances, played? And is this not an element in the origin of everystyle of thinking & doing, not only at the beginning but in the rea-son why people continue? Robert Boyle invested a private fortuneand the Crown spent a public fortune on the Air Pump. Certainlynot for its commercial benets. Certainly out of curiosity, but thehalf of curiosity, a fundamental attribute of the human species, isplay. As Shapin and Schaffer tell us, the Air Pump soon became agentlemans toy, which could be bought from a good maker for veguineas.

That may be an important corrective to characterizing scienticstyles of thinking & doing as ways of nding out. An enormousamount of scientic activity is pursued because it is playful.

23. To do

Many topics arise. Some things to do have already been pointedat. Another is relativism. LT&R was written for Rationality and Rel-ativism. It promised to introduce a whiff of relativism from theheartland of rationality. It did just that. Many are vexed by relativ-ism, whatever that is. Those who most proudly and loudly asserttheir freedom from a search for foundations are often in the closettrembling at that very lack. Happily, for reasons of philosophicalupbringing (Hacking 2007), neither foundationalism nor relativismhave been Big Problems for me, and I tend to regard them as soph-omoric. At any rate, it is best to avoid sweeping generalities andget down to discussable details.7 The English title of the edition referred to here is Homo Ludens: A Study of the Play ElHuizinga himself insisted he meant the Play Element of Culture. For the denitive Dutchhuiz003homo01_01/counterexample to my approach. If Crombies styles are self-authenticating, why not witchcraft too? Others have used whatthey call magical thinking, be it in traditional religions or as sub-cultures of industrial societies. Relativism, or reductio ad absurdumof the styles project, take your pick. This is a sufciently focussedquestion to which the project can reply. For reasons of space, it willhave to do that elsewhere.

There is much else. Work on the project in print says almostnothing about the second group of three styles on Crombies list.They are not even discussed in the Taiwan lectures (Hacking,2009) which are in any case not generally available for copyrightreasons. They were taken up in a series of lectures in Mexico, some40,000 words that need to be put in better order. This will bring outthe extent to which every style is fundamentally different fromevery other. Each has its own personality. In 4 we quoted Crom-bie as saying that his second three styles concern the science of theregularities of populations ordered in space and time. Much moreimportantly they have very different relationships to truth thanmembers of the rst group. For example, we do not say that a tax-onomy is true, so much as apt or explanatory or robust. Moreover,the ways in which at least some of the styles introduce new classesof objects into scientic discourse are fundamentally differentfrom each other.

Then there are more speculative topics that derive from ideas ofcognitive and then ecological history. For example, everything inthis project takes for granted that there is such a thing as Naturestudied by Man. Philippe Descola (2005) convincingly argues thatthis notion of Nature apart from Man is anomalous in human cul-ture. Pierre Hadot (2006) takes a long view of the idea of naturefrom Heraclitus to now. It shows how potent has been the idea thatnature has secretsto be found out. And that is what the styles areup to: they are different ways of nding out.

To what extent have the styles of scientic thinking & doingdetermined our anomalous relationships with nature? How muchof their fascination, in work and play, is the channelling of humancuriosity into nding out the secrets of nature, whose history isnarrated by Hadot? To what extent are the anomalous relation-ships a precondition for the emergence of styles of scientic think-ing? These are among the more interesting topics to be addressed.

Acknowledgements

I thank Jack Ritchie, The University of Cape Town, and the Mel-lon Foundation for organizing the workshop on which the papersin this issue are derived. And great thanks also to those who cameand contributed so much. Finally thanks to innumerable criticsover the years.

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Language, Truth and Reason 30years later1 In the beginning2 LT&R3 Out of anarchy4 Not just thinking5 A rose by any other name...6 NO necessary and sufficient conditions7 Logic8 Whig history9 The three obvious candidates for the template10 The laboratory11 Mutation and continuity12 Ludwik Fleck13 Crystallization14 The autonomy of Crombies styles15 Truthfulness16 Shifts in conceptions of how to tell the truth17 Ontological debates18 The by-product account of ontological debate19 Cognitive history20 Ecological history21 On the cumulative character of styles22 Work and play23 To doAcknowledgementsReferences