This is a pre-print version of a forthcoming paper. For reading only. Please,                          do not share or cite without permission!    Specialisation, Interdisciplinarity, and Incommensurability  Vincenzo Politi  Instituto de Investigaciones Filosóficas, Universidad Nacional Autónoma de México    ABSTRACT Incommensurability may be regarded as driving specialisation, on the one hand,                        and as posing some problems to interdisciplinarity, on the other hand. It may be argued,                              however, that incommensurability plays no role in either specialisation or interdisciplinarity.                      Scientific specialties could be defined as simply ‘different’ (that is, about different things), rather                            than ‘incommensurable’ (that is, competing for the explanation of the same phenomena).                        Interdisciplinarity could be viewed as the co- ordinated effort of scientists possessing                        complementary and interlocking skills, and not as the overcoming of some sort of                          incommensurable divide. This article provides a comprehensive evaluative examination of the                      relations between specialisation, interdisciplinarity, and incommensurability. Its aim is to defend                      the relevance of incommensurability to both specialisation and interdisciplinarity. At the same                        time, it aims at correcting the tendency, common among many philosophers, to regard                          incommensurability in a restrictive manner—such as, for example, as an almost purely semantic                          issue.    1. Introduction  Scientific change is an issue that, in philosophy of science, is often discussed from an intra-                                disciplinary perspective—by analysing, for example, changes within physics, within biology, and                      so on. In this way, the debate on scientific change risks being reduced to the study of how                                    different theories follow one another within disciplines, the boundaries of which are considered                          to remain relatively fixed in time.  Scientific disciplines, however, are themselves historical entities (Toulmin 1962; Lenoir 1997;                      Suárez-Diáz 2009): they may grow, evolve, change, and even lead to the creation of new                              disciplines. This is why it is important to look at scientific change from a more interdisciplinary                                perspective, by considering, for example, those cases when a scientific discipline splits from one                            or more pre-existing disciplines, as in the process of specialisation, or when two or more                              disciplines merge, as in interdisciplinarity.  One of the few philosophers who discusses specialisation within a theory of scientific change                            is Kuhn (2000), who believes that the phenomenon of the proliferation of special- ties is driven                                by incommensurability. However, it may be argued that scientific specialties are not                        ‘incommensurable’ (that is, holding conflicting views about the same range of phenomena), but                          simply ‘different’ (that is, about different ranges of phenomena). Moreover, it is not clear how                              interdisciplinarity would even be possible if it were true that differ- ent specialties were                            separated by incommensurability.  This article provides a comprehensive evaluative examination of the relations between                      specialisation, interdisciplinarity, and incommensurability. Its aim is to explain the relevance of                        incommensurability to specialisation and interdisciplinarity. At the same time, it aims at                        correcting the tendency, common among many philosophers, to regard incommensurability in a                        restrictive manner—such as, for example, as an almost purely semantic issue, having to do with                              meaning variation and communication problems.  In Section 2, Kuhn’s incommensurability thesis is briefly discussed. In Section 3, we explain                            that, in order to understand the role of incommensurability in scientific specialisation, the latter                            must be regarded as a complex historical process. In Section 4, we explain how it is possible that                                    different specialties may become incommensurable through interdisciplinarity. In Section 5, we                      discuss how incommensurability can shed some light on the actual practice of interdisciplinary                          research. We conclude, in Section 6, with some further reflections on incommensurability and                          scientific change.    2. Kuhn’s Incommensurability Thesis  In mathematics, the concept of incommensurability refers to a two-way relation between                        magnitudes lacking a common measure for their comparison. For example, the radius and the                            circumference of a circle are incommensurable, since their ratio cannot be expressed by an                            integer number but, instead, by the irrational number π.  The incommensurability thesis, introduced by Kuhn ([1962] 1996) and Feyerabend (1962), is                        a philosophical thesis about scientific knowledge. Kuhn and Feyerabend used the term                        ‘incommensurability’ metaphorically, to describe the lack of a common measure for the                        objective comparison of two competing paradigms, or theories, or scientific traditions. Since this                          article is concerned with the role of incommensurability in specialisation and interdisciplinarity,                        and since Kuhn developed a model of specialisation as driven by incommensurability, we will                            focus on Kuhn’s version(s) of the incommensurability thesis.  In The Structure of Scientific Revolutions (Kuhn [1962] 1996), incommensurability describes                      the lack of a super-paradigmatic way to evaluate conflicting paradigms during a revolution.                          ‘Paradigm’ being a notoriously polysemous term (Masterman 1970), the ‘lack of a common                          measure between conflicting paradigms’ may mean many things. In its early formulation, indeed,                          Kuhn’s incommensurability thesis refers to: the lack of a shared theoretical vocabulary; the lack                            of shared methodologies for choosing and solving scientific problems, as well as for assessing                            their solutions; the lack of a common way of looking at the world and perceiving                              similarities/dissimilarities relations among problem situations.  Despite the richness of the early formulation of incommensurability, philosophers focused  mainly on its semantic aspects.  On the one hand, many philosophers felt compelled to criticise the so-called contextual theory                            of meaning, on which the semantic aspects of incommensurability rely. Such a theory states that                              the meaning of a word is determined by its theoretical context. It follows that the same word, if                                    used within different linguistic frameworks, may acquire different meanings. This would explain                        why scientists belonging to different scientific traditions appear to talk at cross-purposes and                          may experience occasional communication breakdowns. Putnam (1975) and Kripke (1980)                    developed theories of meaning based on reference stability as a response to semantic                          incommensurability. Kuhn (1990, 2000), however, attacked Putnam’s and Kripke’s views: while                      ‘rigid designation’ can guarantee reference stability, he argued, it is not enough to also guarantee                              meaning stability and avoid incommensurability.  On the other hand, after the publication of Structure, Shapere (1966) argued that the idea of                                meaning variation implying incommunicability across paradigms is contradicted by Kuhn’s own                      historical work, in which past theories are translated in a present-day language. In reply, Kuhn                              (2000) explained that incommensurability is always local, in the sense that it involves only a                              restricted cluster of inter-defined scientific terms. The remaining parts of the scientific (and the                            common) language guarantee cross-paradigmatic communication.  To strengthen the idea of the ‘locality’ of incommensurability, Kuhn began to focus more on                              the analysis of the linguistic/conceptual elements of scientific theories and developed a                        ‘taxonomic’ version of incommensurability. In his mature view, the conceptual structure of a                          scientific theory is constituted by ‘kind terms’, which are ‘taxonomic’ in the sense that they can                                be systematised in a taxonomic fashion. Being taxonomic, the conceptual structure of a scientific                            theory must respect the so-called no-overlap principle, which forbids that an entity can be                            classified as being part of two different kinds (Hacking 1993).  For example, Ptolemy’s and Copernicus’s cosmologies are taxonomically incommensurable,                  because there cannot exist a conceptual taxonomy in which the moon is both a planet (as in the                                    Ptolemaic classification) and a satellite (as in Copernicus’s): such a taxonomy would clearly                          violate the no-overlap principle.  Leaving aside the assessment of its merits, it looks like, at the heart of the local/taxonomic                                incommensurability, there is a strong semantic flavour, also due to Kuhn’s insistence that                          incommensurability leads to ‘translation failures’ between clusters of interdefined kind terms                      (Sankey 1998).  The trend of examining the semantic aspects of incommensurability seems to persist, due in                            part to Kuhn’s own late focus on the linguistic features of scientific theories, which some                              philosophers interpret as the result of a sort of ‘linguistic turn’ (Irzik and Grünberg 1998; Bird                                2002; Gattei 2008).  For example, Sankey (1994) begins his monograph devoted to the incommensurability thesis                        by saying that incommensurability ‘has to do with the nature of the semantic relations between                              the languages employed by scientific theories’ (Sankey 1994, 1). In so doing, he seems to                              assume that the only version of the incommensurability thesis is the semantic one, and that the                                only problems incommensurability poses are about inter-theoretical translatability.  Furthermore, Kuhn’s contextual theory of meaning is still hotly debated. Bird (2000, 2002)                          argues that such a theory inherits the same problems of the theories of meaning developed by the                                  empiricist tradition—that is, by that philosophical tradition that Kuhn aimed to demolish and                          surpass. Read and Sharrock (2002; Sharrock and Read 2002) dis- entangle Putnam’s and                          Kripke’s theories of reference stability, arguing that Kuhn’s arguments were against the former                          but not the latter. They also offer a defence of Kuhn’s theory of meaning, although Bird (2004a,                                  2004b) develops some counterarguments. Kuukkanen (2008, 2010) provides an extensive and                      detailed study of the issue of meaning change in Kuhn’s philosophy and shows, contra Bird, how                                Kuhn’s late theory of meaning, instead of being a disguised version of a rather passé empiricist                                theory, can have some relevance in current analytic philosophy.  This tendency focuses almost exclusively on theories of meanings and translation problems,                        and risks reducing the whole of incommensurability to communication failures. However, not                        only, as we explained, did Kuhn argue that incommensurability does not imply                        incommunicability but, furthermore, communicability does not imply the absence of                    incommensurability.  Methodological incommensurability, for example, poses a problem to scientific practice but it                        has hardly to do with communication failures. As Kuhn (1977) explains, in order to be accepted                                as ‘scientific’, a theory must possess a set of values, namely accuracy, consistency, breadth of                              scope, simplicity and fruitfulness. Such values represent ‘minimal standards’ of scientificity and                        different groups of scientists may ‘weight’ them differently. For example, a group of scientists                            may prefer the theory that is more accurate and consistent, while another group of scientists may                                prefer the theory that carries the promise of being more fruitful. The fundamental disagreement                            over scientific standards has little or nothing to do with problems of translation or with the                                meaning of scientific terms: two groups may continue to disagree even when they fully                            communicate and understand each other, without experiencing any ‘communication breakdown’.  The long debates about Kuhn’s theory of meaning notwithstanding, it looks as though the                            interest for the methodological aspects of incommensurability is regaining momentum among                      philosophers. It has been recently argued, for instance, that some episodes of revolutionary                          scientific change can be better understood as being characterised by methodological rather than                          by semantic incommensurability (Chang 2012). Okasha (2011), who has re-read Kuhn’s view on                          methodological incommensurability through the lenses of social choice theory, has also                      generated a considerable debate—see Bradley (2017 ), Morreau (2015), Okasha (2015), and                        Stegenga (2015).       Finally, the cognitive/perceptual aspects of the early formulation of the incommensurability                      thesis have been expanded upon by Margolis (1993) and, more recently, Bird (2005, 2007).                            Kuhn, it should be recalled, was inspired by the experiments on perception and recognition                            conducted by Bruner and Postman (1949). Inspired by these empirical studies, he conjectured                          that scientists from different paradigms see the world differently. For example, when looking at a                              pendulum, an Aristotelian sees a grave striving to get back to its natural place, whereas a                                Newtonian sees a problem to be solved by applying the laws of motion of classical mechanics. In                                  this sense, incommensurability is a thesis about how scientists belonging to incommensurable                        paradigms see the world (of scientific research) in irreconcilable ways. This is why, for                            philosophers like Bird, incommensurability should be understood with the aid of empirical                        disciplines, such as experimental psychology and the cognitive sciences. In his view, there is                            more to incommensurability than Kuhn’s theory of meaning.  Some philosophers have recently recovered Kuhn’s early analysis of the scientific                      problem-solving practice, and defended the value of a broader notion of incommensurability                        thesis accordingly (Richardson 2002; Rouse 2003, 2013). In this article, we agree with those                            philosophers who claim that incommensurability should not be discussed only in relation to                          theories of meaning and as causing just problems of communication. In fact, we apply a                              broadened view of incommensurability to our understanding of the processes of specialisation                        and interdisciplinarity. Although Kuhn developed his view of incommensurability across                    specialties in his late writings, we suggest that what plays a role in both specialisation and                                interdisciplinarity is something similar to what was described by Kuhn’s early formulation of the                            incommensurability thesis. Rather than focusing on translation problems and theories of                      meaning, that is, we will consider incommensurability as a complex issue involving semantic,                          methodological, and cognitive/perceptual elements.    3. Disciplinary Differentiation and the Dynamics of Specialisation  That contemporary science is characterised by specialisation is a hardly controversial matter of                          fact. Rescher, for example, notices that while specialties in physics numbered 19 in 1911, in                              1954 they were 100 and, by 1970, they were more than 200 (Rescher 1978, 229). It is not just                                      that there are more specialties and sub-disciplines now than in the past but, also, that their                                number keeps growing.  Towards the end of his career, Kuhn (2000) became increasingly interested in the process of                              specialisation, which, in his view, is driven by incommensurability. Having already abandoned                        the concept of a paradigm in favour of the analysis of the linguistic aspects of science, he                                  describes the incommensurability driving specialisation as a conceptual/linguistic barrier that                    makes cross-disciplinary communication difficult. He explains that ‘by barring full                    communication with those outside the group, [incommensurability] maintains their isolation                    from practitioners of other specialties’ (Kuhn 2000, 98). In this sense, incommensurability acts                          as a segregating mechanism that enables the establishment of new specialties by isolating them                            from the pre-existing ones.  One of the problems with the Kuhnian model of specialisation is that it is not entirely clear in                                    which sense different specialties should also be considered as incommensurable. For example,                        Andersen argues that     the conceptual disparity between two different specialties ... is very different from the conceptual                            disparity between the two specialties at each side of a revolutionary divide. Specialties at each side of a                                    revolutionary divide address in some way the same domain and compete on offering the better account of                                  their common domain. This is a relation of incommensurability that may imply severe communication                            difficulties based on, for example, disagreement on which entities exist in the world. On the contrary,                                although different disciplines may address domains that are in some ways partially related, they usually                              do not compete on offering the better—and in the end the only—account.... Hence, focussing on                              communication between different disciplines it is important to bear in mind that in case there is no or little                                      communication between different specialties, this does not necessarily reflect incommensurability but                      may simply reflect the fact that these specialties address issues that are in some way or other unrelated.                                    (Andersen 2012, 273–274)    Andersen develops this argument in several papers (Andersen 2012, 2013a, 2013b, 2016). In her                            view, the supporters of different paradigms during a revolution may experience the occasional                          communication breakdowns associated with incommensurability because they hold and defend                    incompatible and competing views about the same range of problems and phenomena. Scientists                          from different specialties, by contrast, do not find themselves in such a state of competition: their                                research is just about different things. It is not like scientists from different specialties cannot                              communicate in principle; they just do not communicate.  One could reply that different specialties are incommensurable simply in virtue of their being                            different. Such a reply, however, would trivialise the whole concept of incommensurability.                        Intuitively, the idea of incommensurability contains more than mere difference. Theories,                      methods, and paradigms that are about different things may peacefully and unproblematically                        coexist within the ‘Republic of the Sciences’. The incommensurability thesis, however, acquires                        its philosophical relevance in the context of the assessment of competing and conflicting views                            about the same problems—for instance, when an exclusive choice between two incompatible                        paradigms is demanded. Therefore, if one claims that specialties are incommensurable, one                        should also be able to clarify in which sense they are not just different.  However, if specialties were really incommensurable, and not just about different things, then                          it would mean that their domains should at least partially overlap. The problem is that                              specialisation does not seem to lead to the creation of overlapping domains too often. In fact, the                                  process of specialisation seems to be a process of differentiation. Such a process leads to                              ontological fragmentation, with each newly created discipline being focused on its own narrow                          domain. This aspect of specialisation becomes more evident when considering one of the                          examples provided by Wray (2011).  In his recent interpretation of Kuhn, Wray (2011) takes the creation of virology as an example                                of the Kuhnian model of specialisation. Virology was established as an independent discipline                          after some bacteriologists discovered viruses. It turned out that viruses were not a sub-kind of                              bacteria, but a new kind of entities altogether. The new entity called virus could not simply be                                  added as a branch of the pre-existing taxonomy of bacteriology. The discovery of the new kind                                leads to the split of virologists from the community of bacteriologists and to the establishment of                                virology as a separate specialty (Wray 2011, 129–133).  For Wray, the classification systems of viruses and bacteria were ‘taxonomically                      incommensurable’ in the sense briefly explained in section 2: there can be no ​lingua franca in                                which some entities can be classified as being both a virus and a bacterium. Contra Wray (and                                  Kuhn), however, the relation between virology and bacteriology seems to be of difference, rather                            than of incommensurability. The ontological domain of virology does not overlap with the                          ontological domain of bacteriology and the two disciplines are not competing for the explanation                            of the same range of phenomena. In other words: while, for example, the Ptolemaic and                              Copernican classifications provide conflict- ing classifications of the same entities, the celestial                        bodies, and are therefore incommensurable, bacteriology and virology classify different entities.  To understand why it is legitimate to consider incommensurability within a model of                          specialisation, we suggest, it is important to remember that Kuhn’s philosophy looks at science                            from a historical perspective, not as a static body of knowledge. Philosophers like Andersen                            seem to develop their considerations against the idea of incommensurability across specialties by                          looking at how different specialties are now. In this way, they take a ‘presentist’ approach to the                                  current structure of the tree of scientific knowledge. By doing so, they dismiss the very dynamics                                of specialisation. What we are suggesting here, by contrast, is to look at how scientific specialties                                came to be differentiated.  To illustrate this point, we briefly revisit the example of the creation of virology. As Wray                                points out, the creation of virology was driven by the discovery of a new kind, the virus. Such a                                      discovery possesses the same complex historical structure described by Kuhn (1962). To begin                          with, it is not entirely clear when or by whom viruses were actually discovered. Although the                                term ‘virus’ was used, in a very loose sense, in the context of the medical sciences of the                                    nineteenth century, for a long time it was believed that viruses were special types of bacteria.                                That viruses could be different from bacteria was first claimed by Martinus Beijerinck, a scientist                              researching the causes of the so-called mosaic disease affecting plants and flowers. This rather                            common plant disease had been studied for cen- turies, but its pathogen agents were isolated only                                in 1895 by Beijerinck, who maintained that the cause of the infection was not bacteriological.  Beijerinck’s claims generated priority disputes. On the one hand, Adolph Mayer’s earlier                        works on infected tobacco leafs influenced Beijerinck’s research, to the point that it may be                              possible to regard Mayer as the first scientist who observed the new entity. On the other hand, a                                    few years after Beijerinck’s publication, the Russian bacteriologist Dmitrii Ivanovsky claimed                      that he had already discovered the viruses independently.  More importantly, the establishment of the concept of virus as a separate kind of entity was                                met with resistance, if not controversies. Not every scientist was persuaded that Beijerinck,                          Ivanovsky or others had discovered a new natural kind. Quite the opposite: for a long time, the                                  scientific community of bacteriologists tended to regard virus as a sub-kind of bacteria. It must                              be added that the group of virological theorists, in turn, was split between those, like Beijerinck,                                who believed viruses were liquid entities, and those who thought they had a different structure;                              and, furthermore, between those who thought viruses belonged to the living realm and those who                              regarded them as non-living. Even now that virology is an established discipline, disputes about                            the classification of viruses persist, to the point that some argue that the idea of a monistic                                  virological taxonomy should be given up in favour of a pluralistic classification (Morgan 2016).  Some historians read the history of the conceptualisation of virus and the establishment of                            virology as an instance of ‘Kuhnian revolutions’ (van Helvoort 1991, 1992, 1993, 1994).                          Whether one regards the creation of a new specialty as an instance of scientific revolutions or                                not, it remains the point that the specialisation/differentiation process is achieved through                        incommensurability.  During the emergence of virology, but before its establishment as a fully formed and                            independent field of investigation, ‘bacteriological’ and ‘virological’ theories of virus were in a                          state of competition for the explanation of the same range of phenomena and entities—namely,                            for the explanation of the causes of some diseases. Virology, in other words, was established                              through the development of a conception of the causes of the transmission of some disease that                                was in conflict with the bacteriological theories. That now virology and bacteriology are                          different disciplines, with their own separate domain, is beside the point: incommensurability, in                          fact, should be understood as playing a role during the process of specialisation, not after                              specialisation has been accomplished.  Unfortunately, Kuhn himself contributed to confuse this point. In some of his late writings, he                              speaks about scientific revolutions and specialisation in terms of, respectively, ​diachronic and                        synchronic changes ​. Scientific revolutions, for Kuhn, are changes of the first kind, because they                            involve paradigms in temporal succession. Specialisation is a change of the second kind, because                            different specialties do coexist at the same time. Kuhn’s distinction between diachronic and                          synchronic changes, however, does not make too much sense: ‘changes’, by definition, are                          processes unfolding in time. Although, from the historians’ perspective, a scientific revolution                        looks like a succession of paradigms and the tree of science like the collection of coexisting                                specialties, the scientists involved in both kinds of scientific change participate in a process.                            With this in mind, it is easy to see how the controversy between, for example, the phlogiston and                                    the oxygen theory during the so-called chemical revolution and that between the bacteriologist                          and virologist theorists are similar: both controversies were generated by the conflict of                          incommensurable conceptual systems and, at the end of the process, one conceptual system was                            discarded by the other.  Granted that incommensurability plays a crucial role in the process of specialisation/                        differentiation, it remains to understand whether it also plays any role in interdisciplinary                          research.  Kuhn’s view on incommensurability as a conceptual/linguistic barrier hampering cross-                    specialty communication seems to be contradicted de facto by the existence of interdisciplinarity.                          Scientists involved in interdisciplinary research often achieve theoretical and methodological                    integration, which would not be achievable without cross-disciplinary interactions. Also, such a                        view conflicts with Kuhn’s own argument, for which incommensurability does not imply                        incommunicability.  These problems could be solved by considering the earlier and broader version of                          incommensurability. In this section, we have re-discussed Wray’s example of the creation of                          virology with the aim of showing when incommensurability plays a role in the process of                              specialisation. Such an example, being about a new specialty created after the discovery a new                              kind, is consistent with a semantic/taxonomic conception of incommensurability, which Wray                      actually endorses. However, it could be argued that not every specialty is created after the                              discovery of a new kind of entity. Sometimes, new specialties can be created by applying new                                problem-solving methods to old problems. In those cases, what keeps scientific specialties                        separated may be not the impossibility of communication, but methodological and perceptual                        disparities—for further details on this argument, see Politi (2018).  The problem, however, is not to understand whether incommensurability is an obstacle to                          cross-specialty communication but, rather, whether there is any incommensurability across                    specialties after that the process of specialisation/differentiation has been accomplished. This is                        why the next two sections will examine the issue of incommensurability in interdisciplinarity.    4. Disciplinary Convergence and the Dynamics of Interdisciplinarity  The philosophical literature on interdisciplinarity is quickly and steadily growing. Mäki (2016)                        has recently produced a programmatic ‘manifesto’ for the philosophy of interdisciplinarity,                      spelling out many of the desiderata that such a branch of philosophy ought to satisfy. Among                                other things, Mäki hopes that:    Issues of incommensurability will make a comeback, whether semantic, methodological or some other                          variety, responding to the recurrent complaint that the desired communication between disciplines is                          difficult to generate and sustain. Different disciplines often use the same terminologies in different                            meanings, and they may apply different styles and strategies in posing research questions and looking for                                answer to them as well as in assessing the credentials of the answers given. (Mäki 2016, 338)    So far, however, philosophers do not seem to have considered incommensurability— whether                        semantic, methodological or of other kind—as particularly interesting in the context of                        interdisciplinarity.  Some of them have even suggested that incommensurability does not pose any interesting                          problem to interdisciplinarity, since there is not an incommensurable divide separating different                        disciplines to begin with. As mentioned in the previous section, this is what philosophers like                              Andersen argue.  When taking into account the dynamics of specialisation, it is possible to understand how                            disciplinary diversification is achieved through incommensurability. However, even assuming                  that incommensurability plays a formative role during the establishment of new specialties, there                          is little or no reason to presuppose that some sort of incommensurability would persist even after                                the diversification process has been completed. While Andersen may be a bit too hasty when she                                dismisses in toto the idea of incommensurability across specialties, she surely is right when she                              highlights that, no matter how or when they have been differentiated, disciplines which are now                              different are not in a state of competition and, therefore, they are not incommensurable.  Since, in her view, scientific specialties are different and not incommensurable,                      incommensurability plays no role in interdisciplinarity. Instead of being considered as divided by                          some sort of incommensurable barrier which would make interdisciplinarity difficult, the                      disciplines involved in interdisciplinary collaborations are to be thought as complementary and                        the scientists coming from different specialties as possessing interlocking skills.  This conception is further developed by Andersen and Wagenknecht (2013), who apply the                          intra-disciplinary model of epistemic dependence of Hardwig (1985, 1991), based on the idea of                            the joint integration of what different agents know, to interdisciplinary cooperation.  To explain how joint integration works in interdisciplinary research, Andersen and                      Wagenknecht use the example, first used by Darden and Maull (1977), of the cooperation                            between scientists from different biological sub-specialties. In this example, a cytologist’s                      knowledge that ‘the darkly staining bodies within the nuclei of cells which are called                            chromosomes are the likely location of the hereditary material in germ cells’, and a geneticist’s                              knowledge that ‘there are patterns of inheritance and ... there is an entity called a gene that is                                    causally responsible for these patterns’, get somehow integrated by a third scientist, who is able                              to conclude that ‘the chromosomes are the physical location of the genes’ (Andersen and                            Wagenknecht 2013, 1886).  In Andersen and Wagenknecht’s account, cognitive integration seems to be reduced to the                          synthesis of different conceptual/theoretical elements. In their example, interdisciplinary                  integration involves propositions belonging to the theories of cytology and genetics, and the very                            idea of ‘integration’ seems to be akin to the sum of these different theoretical parts.  This account seems to be built on Andersen’s assumption that the disciplines involved in                            interdisciplinarity are not incommensurable, but different and complementary. The risk of such                        an assumption is that ease of integration could somehow be taken for granted, or reduced to an                                  operation as simple as a sum of smaller pieces of knowledge.  In the same way in which incommensurability should not be uncritically presupposed,                        however, the idea that different disciplines are ‘complementary’ and that scientists’ exper- tise is                            indeed ‘interlocking’ should not be taken for granted a priori. Whether scientists coming from                            different specialties have skills and knowledge which can be (more or less easily) integrated for                              the resolution of a complex problem can be determined only within the actual context of                              interdisciplinary problem-solving practice and, often, only after their interdisciplinary                  collaboration has revealed to be fruitful. It would be more correct to say that scientists involved                                in interdisciplinary research have to learn how to make their skills and expertise interlocking.                            This is a process which, as we will see in the next section, may involve the breaking of cognitive                                      and methodological barriers, of the same order of those described by Kuhn’s (early formulation                            of the) incommensurability thesis.  We suggest, once again, to look at interdisciplinarity from a dynamical/historical perspective.                        In virtue of their historical trajectories, different disciplines may become incommensurable when                        they end up converging to an overlapping area. After all, the whole idea of interdisciplinarity is                                founded on the belief that different disciplines may have something to say about a common                              range of problems.  Once they have become ‘about the same range of phenomena’, the different disciplines involved                            in interdisciplinary research may enter in a conflict, for example, about the methods for solving a                                complex problem. This is because, even when different disciplines converge towards the same                          range of problems, each discipline will have its way of conceptualising and modelling such                            problems. As pointed out by Alvargonzález (2011), scientific disciplines are ‘operationally                      closed’ around theories, principles, and material objects (i.e. experimental devices). In virtue of                          their operational closure, the success of the bonding process of two or more disciplines via                              interdisciplinarity cannot be anticipated in any way. In short, interdisciplinarity is not achieved                          by fiat. Rather, it is the result of a process in which, as will be explained in the next section,                                        scientists may experience those kinds of cognitive barriers and fundamental disagreements that                        may go under the label of ‘incommensurability’.    5. Incommensurability and Models of Interdisciplinarity  As argued in the previous section, in interdisciplinary research, different disciplines converge                        towards the same area; it is at this point that they could end up being incommensurable.                                However, we have not shown yet whether that is exactly the case, nor have we shown that, in                                    case there is any, incommensurability actually poses any interesting problems to                      interdisciplinarity.  Even without excluding a priori the existence of some incommensurability across the                        specialties involved in interdisciplinarity, the very existence of interdisciplinary research shows                      that barriers across disciplines can be and are eventually overcome. A philosopher like Andersen,                            then, could accommodate her views and accept the existence of an ‘innocuous’                        incommensurability across disciplines. She may say, for example, that since scientists divide up                          tasks and authority with others, incommensurability issues (which might otherwise be there) are                          somehow sidestepped by keeping engagement to a minimum. This would also be consistent with                            Kuhn’s view that incommensurability does not impede communicability.  If it is residual, minimal and non-threatening, then incommensurability does not seem to pose                            any interesting problem to interdisciplinary collaboration and, therefore, can be treated as a                          non-necessary obstacle for understanding of interdisciplinarity. The advantages of not delving                      too much into incommensurability when talking about interdisciplinarity would be of economical                        order. The cost of dismissing incommensurability in the context of interdisciplinarity, however,                        may be an overly simplistic view of the latter.  Following Holbrook (2013), the most popular view of interdisciplinarity seems to take for                          granted that the end result of interdisciplinary collaborations is a sort of consensus among the                              different parties involved, achieved through integration. Such a view of interdisciplinarity is                        based on what Holbrook calls the ​Habermas-Klein thesis​, from the philosopher Jürgen Habermas                          and Julie Thompson Klein, whose pioneering work opened up the whole field of interdisciplinary                            studies—see, for example, Klein (1990, 1996). The Habermas-Klein thesis states that                      interdisciplinary communication ‘involves the integration of two or more disciplinary languages                      with the aim of generating a common understanding’ (Holbrook 2013, 1869). In this view,                            interdisciplinarity is—or, at least, aims at—integration.  The limit of this model is that it fails to recognise some fundamental (theoretical and                              methodological) differences among disciplines and the obstacles they may pose to                      interdisciplinarity. For Holbrook,    the problem is that theorists of [interdisciplinarity] who want to emphasize difference— including Klein                            herself—currently have no language that does not also appeal to consensus in which to make their case. If                                    interdisciplinary communication is only about reaching con- sensus, then [interdisciplinarity] itself can be                          nothing other than integration—that is, achiev- ing sameness. (Holbrook 2013, 1871)    To Holbrook’s observations, we would also like to add that, as recently argued by several                              philosophers, integration is not necessary to interdisciplinarity. It has been observed, for                        instance, that there can be successful instances of interdisciplinary interactions without                      integration (Grüne-Yanoff 2016). The scientific practice taking place at the frontiers of different                          disciplines may lead to the creation of ‘model-templates’ (Knuuttila and Loettgers 2016),                        ‘repertoires’ (Ankeny and Leonelli 2016) or ‘migrating models’ (Bradley and Thébault 2017),                        which are used by more than one discipline at the same time but without the aim of integrating                                    them. In short, not all the research labelled as ‘interdisciplinary’ aims at integration, but the                              Habermas-Klein thesis fails to capture these instances of interdisciplinarity.  Holbrook suggests two alternative models of interdisciplinarity, based on, respectively: the                      Kuhn-MacIntyre thesis​, which holds that ‘different disciplines are in principle and often in fact                            incommensurable, and so [interdisciplinary] communication can only happen if one first learns                        the language of another discipline from within as a second- first language’ (Holbrook 2013,                            1871); and the ​Bataille-Lyotard thesis ​, for which ‘incommensurability only reveals itself when                        attempts at communication fail (they often succeed), at which point further communication is                          possible only through a process of inventing a new language’ (Holbrook 2013, 1874).  Here, we will not discuss the differences between the Kuhn-MacIntyre thesis and the                          Bataille-Lyotard thesis—differences which seem to be about how to respond to                      incommensurability, whether by second-language learning or through the construction of a new                        language. For the purposes of this article, it is enough to focus on what these two theses have in                                      common: that is, incommensurability.  The incommensurability thesis allows us to shed some light on what the popular view on                              interdisciplinarity cannot explain. It allows us to appreciate the fundamental differences of                        scientific disciplines; to regard ‘integration’ as something more than the sum of different parts;                            and to consider those cases in which interdisciplinary interactions do not lead to integration, and                              even to understand the reasons for when interdisciplinarity fails.  These ideas can be better explained by looking at some recent ethnographical and                          philosophical studies of interdisciplinarity, which show that putting different specialists at work                        for the resolution of some common problems is not an innocent operation. In the                            interdisciplinary practice, in fact, scientists adapt their skills to a set of problems, with problems                              as well as scientists skills needing to be re-shaped accordingly.  In a study conducted on groups working in integrative systems biology, an emerging field                            which seeks the integration of computation and engineering modelling with biological                      experimentation, MacLeod and Nersessian (2016) observe that:    Modelers are not trained as systems biologists, but as a kind of engineer (e.g. electrical or                                telecommunications) and thus prior knowledge often will not help them deal with these uncertainties. The                              importance of their background is not their knowledge of specific engineering systems, but rather their                              particular approach to problem solving which their reference as the ability to ‘think systematically’ and                              ‘debug problems’. This enables them to cope with lack of routines and unstructured task environments.                              Epistemic values that favor precision and exactness that come with handling engineered systems have to                              be transformed when dealing with ‘messy’ biological systems. (MacLeod and Nersessian 2016, 407)    As MacLeod (2018) explains, deeper cognitive reasons may hamper interdisciplinarity. This is                        because one of the consequences of disciplinarity is the development of ​domain-specific                        expertise ​. Because of their domain-specific preparation, scientists from different disciplines may                      encounter serious difficulties in an interdisciplinary setting. Some practices may be too opaque                          for the outsiders of a particular domain. Furthermore, scientists coming from different fields and                            trained to the resolution of different domain-specific problems may experience conflicts in the                          application of some epistemic values for choosing the best problem-solving approach. Finally,                        the very ways in which the problems to be solved are defined and framed in an interdisciplinary                                  environment may remain vague for a long time.  Another consequence of disciplinarity is a strong sense of ​epistemic identity (Osbeck and                          Nersessian 2017). On the one hand, epistemic identities shape and influence the cognitive                          practices of the members of the same discipline; on the other hand, they may create obstacles for                                  the collaboration of scientists coming from different scientific communities. Three points                      deserves to be highlighted. First, we are not just assuming the existence of incommensurability.                            Rather, incommensurability is a hypothesis we are making on the basis of the empirical evidence                              collected in the course of several empirical studies— such as the five-year ethnographic study of                              two systems biology labs, conducted by Nancy J. Nersessian and her team, which have produced,                              among other things, the studies cited in the previous paragraphs.  Second, in these studies, integration appears to exceed the sum of different elements. Far from                              being an activity in which different pieces of knowledge somehow interlock with one another,                            interdisciplinarity looks more like a transformative activity, in which the actors involved have to                            modify some of their beliefs, adapt their knowledge and devise new problem-solving methods.  Third, we claim that what emerges from these empirical studies is something closer to Kuhn’s                              early formulation of the incommensurability thesis. As mentioned in section 2, in The Structure                            of Scientific Revolutions, the incommensurability thesis describes the disparity not only between                        theoretical languages, but also between problem-solving methods, values, and research agendas.                      In its early formulation, that is, the incommensurability thesis seemed to capture more of the                              actual problems that scientists encounter in scientific practice.  The problem faced by interdisciplinary research is that finding a way to communicate across                            specialties may be necessary but not sufficient for successful problem-solving. Scientists from                        different disciplines may understand each other’s theoretical language and communicate with                      one another with not too many problems. This does not mean, however, that they will all agree                                  about the methods to employ and the problem-solving strategies to implement. This is all the                              more evident in those cases in which the knowledge and expertise to be integrated is not only                                  theoretical, as in the example of Andersen and Wagenknecht discussed in the previous section,                            and in which interdisciplinary collaborations involve theoreticians, on the one hand, and                        experimentalists, on the other hand.  Holbrook (2013) has developed some philosophical models of interdisciplinarity that take into                        account incommensurability; the Nersessian team has produced empirical evidence of the                      difficulties of interdisciplinary collaboration, but without invoking the concept of                    incommensurability. In this section, we have used the results of the latter to provide empirical                              evidence for the philosophical models of the former. This has been done by considering                            interdisciplinary research as an instance of scientific change in which, as explained in section 4,                              different disciplines become incommensurable when they converge towards the same area of                        investigation.    6. Concluding Remarks on Incommensurability and Scientific Change(s)  We have considered both specialisation and interdisciplinarity as types of scientific changes                        subjected to incommensurability. On doing so, we have also attempted to correct some of the                              misconceptions about the incommensurability thesis. In this concluding section, we want to                        highlight some of the aspects of the incommensurability thesis which we have brought up in this                                article.  To begin with, ‘incommensurability’ is not the same thing as mere ‘difference’.                        Incommensurable paradigms are in a state of competition and the results of this competition                            cannot be decided objectively, because there is no absolute method to guide scientists in their                              choices. Different disciplines, by contrast, do not compete, because they are about different                          domains of investigations. That incommensurability cannot be reduced to differ- ence                      complicates the assessment of its role in specialisation and interdisciplinarity, which are,                        respectively, the proliferation, on the one hand, and the convergence, on the other hand, of                              different disciplines. As we argued, however, if specialisation and incommensurability are                      considered from a dynamic/historical perspective, and as processes unfolding through time, then                        the role incommensurability plays in both processes, when it plays it and which obstacles it may                                create appear clearer.  We have also endorsed Kuhn’s early version of the incommensurability thesis, con taining not                            only semantic but also methodological and cognitive/perceptual aspects. One may wonder                      whether there would be much value remaining in the incommensurability thesis if it is expanded                              to include such a wide range of (methodological, cognitive, perceptual) disparities. Perhaps, one                          of the reasons for why philosophers (and Kuhn himself) went for a more restricted semantic                              notion of incommensurability is that it is a less vague and more analysable and relatively                              constrained notion. This point forces us to consider what do we expect from the                            incommensurability thesis (and, in general, from philosophy of science).  Kuhn abandoned the heavily criticised concept of a ‘paradigm’ and focused on the                          philosophical more familiar (but not necessarily clearer) concept of a ‘scientific theory’. As a                            consequence, incommensurability ceased to be ‘the lack of a common measure between                        paradigms’ and became ‘the lack of a common language between some restricted parts of two                              scientific theories’. That the semantic version of incommensurability is more precise does not                          imply that it is also more adequate to capture some of the fundamental problems arising in the                                  complex and multi-faceted practice of science.  As said in section 2, when Kuhn and Feyerabend introduced the incommensurability thesis,                          they used ‘incommensurability’ in a metaphorical way. Indeed, one of the difficulties with the                            incommensurability thesis is trying to understand what the ‘lack of a common measure’ exactly                            amounts to and which entities lacking such a common measure precisely are. Scientific activity                            not being a monolith, it may be that the relata of incommensurability are different from case to                                  case: sometimes incommensurability is the lack of a common conceptual system, other times of a                              common way of applying scientific values, and so on. Yet, the relation of incommensurability                            always expresses fundamental disagreements on how to conduct science. The multi-faceted                      nature of incommensurability reflects the complex nature of science.  At this point, it is crucial to stress that incommensurability is not being expanded to the point                                  of including any sort of disparities whatsoever. Disagreement is often endemic to scientific                          research. While in a situation of ‘normal research’ disagreements can be more or less easily                              resolved, the type of disagreements incommensurability gives rise to lead to non-cumulative                        changes. In Structure, Kuhn examined only one type of non-cumulative changes: the so-called                          scientific revolutions. However, the ontological fragmentation accomplished by specialisation                  and the integration of part of different disciplines occur- ring via interdisciplinarity can also be                              regarded as non-cumulative changes driven by incommensurability.  Finally, it should not be forgotten that, in ​The Structure of Scientific Revolutions​, Kuhn used                              the incommensurability thesis within a theory of scientific progress, in which science is                          described not as tending towards an ultimate truth but, rather, as being pushed from behind by its                                  previous accomplishments and failures. Whether science does get closer to the truth is an issue                              that, like scientific change, tends to be considered from a merely inter-disciplinary perspective.                          This article has offered a systematic analysis of the relation between incommensurability,                        specialisation, and interdisciplinarity. Whether the processes of specialisation and                  interdisciplinarity can shed some new light on the issue of scientific realism is something to be                                destined to future work.      Acknowledgements  This paper was written during a period of postdoctoral research on the project ‘Inter-field                            Scientific Change’ at the Instituto de Investigaciones Filosóficas of UNAM (Mexico), under the                          supervision of Prof. Atocha Aliseda. I also thank two anonymous reviewers of this journal for                              critical comments that improved the earlier version of this text.    References  Alvargonzález, David. 2011. “Multidisciplinarity, Interdisciplinarity, Transdisciplinarity, and the                Sciences.” ​International Studies in the Philosophy of Science​ 25: 387–403.   Andersen, Hanne. 2012. “Conceptual Development in Interdisciplinary Research.” In ​Scientific                    Concepts and Investigative Practice​, edited by Uljana Feest and Friedrich Steinle, 271–292.                        Berlin: Walter de Gruyter.   Andersen, Hanne. 2013a. “Bridging Disciplines: Conceptual Development in Interdisciplinary                  Groups.” In ​Classification and Evolution in Biology, Linguistics and the History of Science​,                          edited by Frangerau Heiner, Hans Geisler, Thorsten Halling, and William Martin, 33–44.                        Stuttgart: Franz Steiner Verlag.   Andersen, Hanne. 2013b. “The Second Essential Tension: On Tradition and Innovation in                        Interdisciplinary Research.” ​Topoi ​ 32: 3–8.   Andersen, Hanne. 2016. “Collaboration, Interdisciplinarity, and the Epistemology of                  Contemporary Science.” ​ Studies in History and Philosophy of Science Part A 56: 1–10.   Andersen, Hanne, and Susann Wagenknecht. 2013. “Epistemic Dependence in Interdisciplinary                    Groups.” ​Synthese ​ 190: 1881–1898.  Ankeny, Rachel A., and Sabina Leonelli. 2016. “Repertoires: A Post-Kuhnian Perspective on                        Scientific Change and Collaborative Research.” ​Studies in History and Philosophy of Science                        Part A ​ 60: 18–28.   Bird, Alexander. 2000. ​Thomas Kuhn​. Chesham: Acumen.   Bird, Alexander. 2002. “Kuhn’s Wrong Turning.” ​Studies in History and Philosophy of Science                          Part A ​ 33: 443–463.   Bird, Alexander. 2004a. “Three Conservative Kuhns.” ​Social Epistemology ​ 17: 127–133  Bird, Alexander. 2004b. “Kuhn on Reference and Essence.” ​Philosophia Scientae​ 8: 39–71.   Bird, Alexander. 2005. “Naturalizing Kuhn.” ​Proceedings of the Aristotelian Society 105:                      109–127.     Bird, Alexander. 2007. “Incommensurability Naturalized.” In ​Rethinking Scientific Change and                    Theory Comparison: Stabilities, Ruptures, Incommensurabilities?​, edited by Léna Soler, Howard                    Sankey, and Paul Hoyningen-Huene, 21–39. Dordrecht: Springer.   Bradley, Seamus. 2017. “Constraints on Rational Theory Choice.” ​The British Journal for the                          Philosophy of Science ​ 68: 639–661.   Bradley, Seamus, and Karim P. Y. Thébault. 2017. “Models on the Move: Migration and                            Imperialism.” ​ Studies in History and Philosophy of Science, forthcoming.   Bruner, Harold Jerome I. and Leo Postman. 1949. “On the Perception of Incongruity: A                            Paradigm.” ​Journal of Personality ​ 18: 206–223.   Chang, Hasok. 2012. “Incommensurability: Revisiting the Chemical Revolution.” In ​Kuhn’s                    ‘The Structure of Scientific Revolutions’ Revisited​, edited by Vasso Kindi and Theodore                        Arabatzis, 153–177. New York: Routledge.   Darden, Lindley, and Nancy Maull. 1977. “Interfield Theories.” ​Philosophy of Science 44:                        43–64.   Feyerabend, Paul K. 1962. “Explanation, Reduction and Empiricism.” In ​Scientific Explanation ​,                      Space, and Time, edited by Herbert Feigl and Grover Maxwell, 28–97. Minneapolis: University                          of Minnesota Press.   Gattei, Stefano. 2008. Thomas Kuhn’s ‘Linguistic Turn’ and the Legacy of Logical Empiricism.                          Aldershot: Ashgate.   Grüne-Yanoff, Till. 2016. “Interdisciplinary Success Without Integration.” ​European Journal for                    Philosophy of Science ​ 6: 343–360.   Hacking, Ian. 1993. “Working in a New World: The Taxonomic Solution.” In ​World Changes:                            Thomas Kuhn and the Nature of Science​, edited by Paul Horwich, 275–310. Cambridge: MIT                            Press.   Hardwig, John. 1985. “Epistemic Dependence.” ​The Journal of Philosophy 82: 335–349.                      Hardwig, John. 1991. “The Role of Trust in Knowledge.” ​The Journal of Philosophy 88:                            693–708.   Holbrook, Britt J. 2013.“What Is Interdisciplinary Communication? Reflections on the Very Idea                        of Disciplinary Integration.”​ Synthese ​190: 1865–1879.   Irzik, Gürol, and Teo Grünberg. 1998. “Whorfian Variations on Kantian Themes: Kuhn’s                        Linguistic Turn.” ​ Studies in History and Philosophy of Science Part A 29: 207–221.   Klein, Julie T. 1990. ​Interdisciplinarity: History, Theory, and Practice. ​Detroit, MI: Wayne State                          University Press.   Klein, Julie T. 1996. Crossing Boundaries: Knowledge, Disciplinarities, and                  Interdisciplinarities. ​Charlottesville: University Press of Virginia.   Knuuttila, Tarja, and Andrea Loettgers. 2016. “Model Templates within and between                      Disciplines: From Magnets to Gases—and Socio-economic Systems.” ​European Journal for                    Philosophy of Science ​ 6: 377–400.   Kripke, Saul. 1980. ​Naming and Necessity. ​ Cambridge, MA: Harvard University Press.   Kuhn, Thomas S. 1962. “The Historical Structure of Scientific Discovery.” ​Science 136:                        760–764.   Kuhn, Thomas S. [1962] 1996. ​The Structure of Scientific Revolutions. 3rd ed. Chicago,                          IL:University of Chicago Press.   Kuhn, Thomas S. 1977. “Objectivity, Value Judgment, and Theory Choice.” In ​The Essential                          Tension: Selected Studies in Scientific Tradition and Change ​, edited by Thomas S. Kuhn, 320–                            339. Chicago, IL: University of Chicago Press.   Kuhn, Thomas S. 1990. “Dubbing and Redubbing: The Vulnerability of Rigid Designation.” In                          Scientific Theories ​, edited by Wade C. Savage, 58–89. Minneapolis: University of Minnesota                        Press.   Kuhn, Thomas S. 2000. ​The Road Since Structure: Philosophical Essays, 1970–1993, with an                          Autobiographical Interview. Edited by James Conant and John Haugeland. Chicago, IL:                      University of Chicago Press.   Kuukkanen, Jouni-Matti. 2008. ​Meaning Changes: A Study of Thomas Kuhn’s Philosophy.                      Saarbrucken: Verlag Dr. Müller.   Kuukkanen, Jouni-Matti. 2010. “Kuhn on Essentialism and the Causal Theory of Reference.”                        Philosophy of Science ​ 77: 544–564.   Lenoir, Timothy. 1997. “The Discipline of Nature and the Nature of Disciplines.” In I​nstituting                            Science: The Cultural Production of Scientific Disciplines​, edited by Timothy Lenoir, 45–74.                        Stanford, CA: Stanford University Press.   MacLeod, Miles. 2018. “What Makes Interdisciplinarity Difficult? Some Consequences of                    Domain Specificity in Interdisciplinary Practice.” ​Synthese ​195: 697–720.  MacLeod, Miles, and Nancy J. Nersessian. 2016. “Interdisciplinary Problem-solving: Emerging                    Modes in Integrative Systems Biology.” ​European Journal for Philosophy of Science 6:                        401–418.   Mäki, Uskali. 2016. “Philosophy of Interdisciplinarity: What? Why? How?” ​European Journal                      for Philosophy of Science ​6: 327–342.   Margolis, Howard. 1993. Paradigms and Barriers: How Habits of Mind Govern Scientific                        Beliefs. ​Chicago, IL: University of Chicago Press.   Masterman, Margaret. 1970. “The Nature of a Paradigm.” In ​Criticism and the Growth of                            Knowledge ​, edited by Imre Lakatos and Alan Musgrave, 59–89. Cambridge: Cambridge                      University Press.   Morgan, Gregory J. 2016. “What Is a Virus Species? Radical Pluralism in Viral Taxonomy.”                            Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of                              Biological and Biomedical Sciences ​59: 64–70.   Morreau, Michael. 2015. “Theory Choice and Social Choice: Kuhn Vindicated.” ​Mind 124:                        239–262.   Okasha, Samir. 2011. “Theory Choice and Social Choice: Kuhn Versus Arrow.” ​Mind 120:                          83–115.   Okasha, Samir. 2015. “On Arrow’s Theorem and Scientific Rationality: Reply to Morreau and  Stegenga.” ​Mind ​ 124: 279–294.   Osbeck, Lisa M., and Nancy J. Nersessian. 2017. “Epistemic Identities in Interdisciplinary                        Science.” ​Perspectives on Science​ 25: 226–260.   Politi, Vincenzo. 2018. “Specialization and the Incommensurability Among Scientific                  Specialties.” Under review.   Putnam, Hilary. 1975. “The Meaning of ‘Meaning’.” In ​Mind, Language and Reality:                        Philosophical Papers. Vol. 2, edited by Hilary Putnam, 215–271. Cambridge: Cambridge                      University Press.   Read, Rupert, and Wes Sharrock. 2002. “Thomas Kuhn’s Misunderstood Relation to Kripke-                        Putnam Essentialism.” ​ Journal for General Philosophy of Science ​33: 151–158 ​.   Rescher, Nicholas. 1978. Scientific Progress: A Philosophical Essay on the Economics of                        Research in Natural Science.​ Pittsburgh, PA: University of Pittsburgh Press.   Richardson, Alan W. 2002. “Narrating the History of Reason Itself: Friedman, Kuhn, and a                            Constitutive a Priori for the Twenty-first Century.” ​Perspectives on Science​ 10: 253–274.   Rouse, Jospeh. 2003. “Kuhn’s Philosophy of Scientific Practice.” In ​Thomas Kuhn​, edited by                          Thomas Nickles, 101–121. Cambridge: Cambridge University Press.   Rouse, Joseph. 2013. “Recovering Thomas Kuhn.” ​Topoi​ 32: 59–64.   Sankey, Howard. 1994. ​The Incommensurability Thesis ​. Aldershot: Ashgate.   Sankey, Howard. 1998. “Taxonomic Incommensurability.” ​International Studies in the                  Philosophy of Science ​ 12: 7–16.   Shapere, Dudley. 1966. “Meaning and Scientific Change.” In ​Mind and Cosmos: Essays in                          Contemporary Science and Philosophy ​, edited by Robert Colodny, 41–85. Pittsburgh, PA:                      University of Pittsburgh Press.   Sharrock, Wes, and Rupert Read. 2002. ​Kuhn: Philosopher of Scientific Revolutions. Oxford:                        Polity.   Stegenga ​, ​Jacob. 2015. “Theory Choice and Social Choice: Okasha Versus Sen.” ​Mind 124:                          263–277.   Suárez-Diáz, Edna. 2009. “Molecular Evolution: Concepts and the Origin of Disciplines.”                      Studies in History and Philosophy of Biological and Biomedical Sciences​ 40: 43–53.   Toulmin, Stephen. 1962. ​Human Understanding.​ Vol. 1. Oxford: Clarendon Press.   van Helvoort, Ton. 1991. “What Is a Virus? The Case of Tobacco Mosaic Disease.” ​Studies in                                History and Philosophy of Science​ 22: 577–588.   van Helvoort, Ton. 1992. “Bacteriological and Physiological Research Styles in the Early                        Controversy on the Nature of the Bacteriophage Phenomenon.” ​Medical History​ 36: 243–270.   van Helvoort, Ton. 1993. “A Bacteriological Paradigm in Influenza Research in the First Half of                              the Twentieth Century.” ​History and Philosophy of the Life Sciences​ 15: 3–21.   van Helvoort, Ton. 1994. “History of Virus Research in the Twentieth Century: The Problem of                              Conceptual Continuity.” ​History of Science​ 32: 185–235.   Wray, K. Brad. 2011. ​Kuhn’s Evolutionary Social Epistemology. Cambridge: Cambridge                    University Press.