The question of how much ‘order’ there is in the universe and how science should engage with it has long been a crucial part of philosophy of science. To answer that question philosophers developed the concept of the ‘Unity of Science’ that came to be the dominating framework in which philosophers of science put forward their ideas. According to this approach, often referred to as monism, sciences should restrict themselves to certain ‘privileged’ scientific theories that prove to be the best at meeting the values of scientific community. However, it has been illustrated by the proponents of a different philosophical position called ‘pluralism’ that this monistic approach is in many ways detrimental to science, as it leads to a ‘loss of knowledge’. In this essay I shall compare two pluralistic positions proposed by two different philosophers of science: Hasok Chang and John Dupré. I shall analyze both concepts and investigate which one of them would be more applicable to the actual scientific practice and, hence, would constitute a better normative account for science.
Before we proceed any further, it is essential to examine the context in which the philosophical position of pluralism was developed: it was in a sense a reaction to the prevalent philosophical approach that was concerned with the so-called ‘Unity of Science’. So, what is the unity of science and how is the pluralistic position different from that view? The unity of science as a program was originally devised by logical positivists who were concerned with the notions of objectivity and verifiability of scientific statements. The concept, however, came to have different meanings; according to revisionist history, the Vienna Circle advocated unity in sciences in order to be able to translate between different scientific disciplines: notably, Carnap argued that ‘both biological and physical laws could be expressed in terms of everyday physical terms and procedures’ (Galison, 1996, p. 5). However, the unity of science came to be primarily associated not with this ‘reduction of language’ but with ontological and epistemic reductionism: ‘the great ‘natural’ span of the sciences built solidly one layer upon the next, from the laws of elementary particle physics up through the atomic, molecular, cellular, multicellular, psychological, and social sciences’ (Ibid, p. 5). This in turn forms a crucial part of a philosophical position called monism, according to which the fundamental aim of science is to create a single comprehensive theory of the natural world. Pluralism emerged as a reaction to this view, since, from the pluralist perspective, science should, on the contrary, strive to provide multiple accounts of the natural world, as different projects of scientific inquiry provide us with different kinds of knowledge.
In the following section of this essay I shall now outline Hasok Chang’s philosophical position. To begin with, a fundamental part of Hasok Chang’s philosophy of science deals with providing a different perspective on the realism/anti-realism debate. He uses the example of water to claim that no single scientific theory can provide us with the ‘ultimate truth’: he argues that the notion of water as ‘H2O’ is in fact an idealized model. He states that there are many possible scientific accounts on the constitution of water:
It is also an electrostatic combination of electropositive hydrogen and electronegative oxygen, which can be broken up in a battery. It is also a one-to-one combination of hydrogen and oxygen “atoms” (in the weight-only system). It is also an element from which one can produce hydrogen and oxygen gas by the addition or subtraction of phlogiston. And so on (Chang, 2012, p. 213).
In providing this pluralistic view of scientific theories he also puts forward radical ideas that challenge the traditional philosophical accounts. In particular, he argues that science should be considered as a combination of ‘systems of practice’ rather than a bundle of abstract statements and theories, since, according to him, science is primarily an experimental activity and the source of scientific knowledge is primarily rooted in practice: ‘All scientific work, including pure theorizing, consists of actions – physical, mental and ‘paper-and-pencil’ operations’ (Ibid, p. 15). Hence, he calls his position ‘active realism’. This emphasis on practice is also articulated in Ian Hacking’s philosophy, known as ‘entity realism’ (Hacking, 1998). However, in contrast with Ian Hacking, Chang is not concerned with the reality of ‘unobservable entities’. Rather, he emphasizes the importance of the shift from ‘justified true beliefs’ to ‘systems of practice’ and views knowledge as an ability rather than facts or statements. In fact Chang states that in his book when referring to Hacking’s position:
Hacking’s focus is not quite right when he drives his arguments toward conclusions of the form “We know for certain that X is real”. Rather, the main appeal of Hacking’s experimental realism, as well as Bridgman’s operationalism, should be seen as the exhortation to go ﬁnd more ways of engaging with reality (Chang, 2012, p. 244).
The adherence to a particular system in science, leads to a loss of knowledge and he uses the case of the phlogiston theory to illustrate this. Despite now being recognized as a pseudoscientific concept, it was immensely successful and was not, as Chang puts it, ‘so bad whiggishly speaking’ (Chang, 2009, p. 246). It did provide us with ‘practical knowledge’ that Lavoisier’s chemistry did not: for example, with regard to chemical potential energy and common properties of metals (Ibid). What is more, it would have led to a much earlier discovery of the electron:
Only after more than a 100 years could the explanatory potential of the phlogiston theory be regained in modern chemistry. One had to wait until the advent of the electron theory of metals towards the end of the 19th century (Hoyningen-Huene cited in Chang, 2009, p. 247).
Hence, in many ways science would have benefitted if scientists had not abandoned the phlogiston theory. Chang’s pluralism, therefore, calls for inclusion of multiple ‘systems of practice’ that would provide us with different kinds of ‘practical’ knowledge. In this sense, Chang’s democratic view of the normative account is asymmetric to Kuhn’s monistic idea of ‘paradigms’ and ‘puzzle-solving’, according to which scientists’ dogmatic adherence to a particular scientific theory, on the contrary, makes science more productive (Kuhn, 1970).
In the following section I shall consider John Dupré’s philosophy of science and provide a description of the kind of pluralism that he advocates. To be begin with, a crucial part of John Dupré’s concept is concerned with metaphysics: the ultimate nature of things that exist in the universe. In his book The Disorder of Things he criticizes the prevailing monistic approach and proposes a new set of metaphysical claims and his own view of natural kinds, groupings that are not devised by humans but are inherent in nature. Dupré’s concept of natural kinds is neither essentialist nor nominalist: according to the former view, the members of a kind share certain ‘essential properties’ that form the basis for classification in science, whereas the latter view denies the existence of such inherent properties and, hence, claims that there are no ‘natural kinds’, but only individuals. In contrast to both of these views, Dupré puts forward the idea of a pluralist metaphysics, according to which natural kinds do not have one ‘essential’ property, but have many of them: ‘I suggest that many individual things are objectively members of many individual kinds. Thus I, for example, am a human, a primate, a male, a philosophy professor, and many other things’ (Dupré, 1996, p. 105). What is more, he argues that ‘all, or at least many’ of these natural kinds are ‘perfectly real’ and none of them should be considered to be the ‘one’, since individuals ‘naturally’ possess multiple ‘essences’ and therefore belong to a number of multiple ‘natural’ kinds (Ibid, p. 105). These claims lay the foundations for Dupré concept of ‘metaphysical disorder’, which he uses to support the pluralist position concerning the nature of science, namely, the idea of ‘disunity of science’, also advocated by Hasok Chang. He, hence, argues that scientists should not restrict themselves to a single project of scientific inquiry, since, according to him it is not possible to come up with a single criterion that would determine which projects of scientific inquiry should be pursued. According to him, ‘rather than seeking a criterion of scientificity, we should attempt to develop a catalogue of epistemic virtues’ (Dupré, 1993, p. 10). While being a pluralist, he distinguishes between ‘good’ science and ‘bad science’ and argues that in choosing between two projects of scientific inquiry ‘we should select that project that best serves the goals that motivate our inquiry’ (Dupré, 1996, p. 106). This position in a way requires something that Pierre Duhem referred to as ‘good sense’, since, according to Dupré, the choice between scientific theories does not depend on a single objective criterion (Duhem, 1998).
So, what are the differences between these two philosophical accounts? In the next section of my essay I shall compare these philosophical positions and identify the differences between these two kinds of pluralistic concepts as put forward by Dupré and Chang. To begin with, while both philosophers subscribe to the idea of pluralism, they also both consider themselves to be realists. However, despite this terminological commonality, the concepts proposed by these philosophers offer different kinds of pluralism and, hence, provide slightly different perspectives on the nature of science. The fundamental difference between these two positions is that Dupré is concerned with the metaphysical basis, whereas Chang’s account is epistemic. Dupré’s philosophy provides us with insights on the ultimate nature of things, while Chang’s philosophy of science primarily deals with science as a practice that enables us to gain knowledge about the natural world. As I have illustrated earlier in this essay, Dupré believes that the reality is complex and is indeed ‘many things’, whereas Chang does not make those kind of metaphysical statements; rather, he believes, as in the case with water, the reality can be described as ‘many things’. While acknowledging that metaphysical pluralism is ‘esthetically beautiful’, he is reluctant to make claims regarding the ‘way the world is’ since they are not be verifiable: ‘it is not possible to support any metaphysical premises well enough’, since ‘the true shape of reality is not directly accessible to us’ (Chang, 2012, p. 292).
In his book The Disorder of Things Dupré, when attempting to classify his philosophical position, states that his account is compatible with realism: ‘I can see no possible reason why commitment to many overlapping kinds of things should threaten the reality of any of them’ (Dupré, 1993, p. 262). Hence, Dupré’s philosophical position, which he calls ‘promiscuous realism’ is in fact a combination of realism and pluralism: since the reality is itself ‘complex’, it is rational to belief in the truth of many overlapping scientific theories. Hasok Chang’s philosophy, on the other hand, is not realist in that sense. According to his definition, reality is ‘whatever resists our own will’ and it is essential to maximize our exposure to it by having multiple systems of scientific practice (Chang, 2012, p. 220). However, Chang’s philosophy does not concern itself with the ‘truth’ of scientific theories. In fact, his view of knowledge as an ‘ability’, and his emphasis on the ‘practical knowledge’ rather than the truth-content of theories, as in the case with the phlogiston theory, makes his account more compatible with the philosophical position of ‘constructive empiricism’ and the notion of ‘empirical adequacy’ as put forward by Van Fraassen (Van Fraassen, 1998).
So, which philosophical position provides a better normative account for science? Is metaphysical pluralism essential for science or is the epistemic position sufficient for scientists to pursue multiple projects of scientific inquiry? To begin with, Hasok Chang refers to his philosophy as ‘active normative epistemic pluralism’, hence his position involves a number of constituents. However, I shall focus on the ‘epistemic’ nature of his philosophy in order to contrast it with Dupré’s metaphysical account. First of all, it can be argued that it is the epistemological position that should provide scientists with the normative account, since it is epistemology that is concerned with gaining scientific knowledge. Chang states that his epistemological pluralism is ‘aimed at improving the ways in which we go about acquiring knowledge, rather than at elucidating the fundamental ontology of nature’ (Chang, 2012, p. 268). According to him, the ‘way the world’ is an open empirical question and, what is more, he claims that it in fact it does not have any impact on the way science is carried out. Hence, Chang’s position can be seen as more rational and ‘scientific’ in the sense that it does not make any assumptions that cannot be verified. Therefore, his position regarding metaphysics is close to the one advocated by logical positivists, who considered metaphysical statements ‘unverifiable’, and hence, meaningless: ‘what we know for reasonably sure is that the world is difficult for humans to fathom, not that it is either complex or simple in some absolute sense’ (Chang, 2012, p. 293). Thus, Chang’s position, as he himself points out, also advocates ‘humility’ as opposed to ‘hubris’. However, Hasok Chang’s rejection of the notion of ‘truth’ could prove to be impractical, in particular, with regard to demarcation between science and pseudoscience. On the other hand, Chang’s account is at the same time more ‘democratic’ and ‘liberal’ than Dupré’s philosophical position in the sense that it is not committed to any kind of metaphysical claims and, hence, would prove to be better normative account for scientists keen on producing ‘practical knowledge’, rather than discovering the fundamental ‘truth’.
As I have mentioned earlier, Chang argues that claims regarding the fundamental nature of things are irrelevant to scientific inquiry and, therefore, states that science should not be concerned with ‘some metaphysical hubris about how we can obtain or have obtained objective truth’ (Chang, 2012, p. 217). By contrast, in his book Disorder of Things Dupré illustrates how metaphysical monism, essentialism in particular, in particular, can have a detrimental effect on the progress of science as well as broader political and social implications. In particular, he considers certain dichotomies, such as homosexuality/heterosexuality and male/female, and states that essentialism regarding these categories can lead to discrimination against certain people, since they are viewed as members of distinct ‘natural kinds’:
Of most obvious significance to my concern here, it licenses the search for further characteristics of the supposed kinds, and for the underlying (perhaps even essential) features (genes, hormones, and so on) responsible for those characteristics. Indirectly this may legitimate behavioral stereotypes and to reinforce the assumptions of heterosexuality as the ‘normal’ type and of homosexuality as pathological (Dupré, 1993, p. 253).
According to Dupré, particular views regarding metaphysics play an important part in scientific practice. Though indirectly, they affect the way science is carried out by creating ‘powerful’ assumptions’ about the ‘way the world is’:
Aristotle’s picture of the natural ordering of basic substances in concentric circles and Newton’s vision of a universe of massive objects moving through an infinite void were not the products of empirical inquiry, but set of assumptions that proved among the most fruitful in history in suggesting strategies of investigation and in interpreting the results of those investigations (Ibid, p. 2).
Therefore, from this point of view, an appropriate, pluralistic metaphysics is not only plausible, as Dupré has illustrated, but is also essential, as it provides a justification for epistemological pluralism that Hasok Chang argues for. What is more, Dupré argues that epistemological pluralism is not sufficient as a normative account, since it could be that ‘science is disunified simply because it has not yet been unified’ (Dupré, 1996, p. 102). Therefore, to get rid of epistemological pluralism it is essential to reject metaphysical monism, a consequence of which would be that disunity in science is its ‘inevitable and appropriate condition’ (Ibid, p. 102).
In addition to this, this debate between epistemological and metaphysical pluralism is in a way close to the realism/anti-realism debate in the monist framework. While the former is concerned with the fundamental nature of things, the latter does not attach any truth- content to the theories. Both positions offer different versions of pluralism as a normative account and both possess strengths in different aspects. In particular, one of the strength of realism and in this case Dupré’s ‘promiscous realism’, is the motivating component: the idea that scientists are discovering the fundamental nature of the universe, which from the metaphysical pluralist perspective is ‘complex’ but is still intelligible.
To sum up, in this essay I have compared Hasok Chang and John Dupré’s pluralist philosophical positions and have investigated the benefits of each as a normative account for science. While Hasok Chang’s account emphasizes the importance of having multiple systems of scientific practice and views knowledge as ‘ability’ rather than ‘justified true belief’, Dupré is concerned with the fundamental nature of the natural world and argues that metaphysical assumption play an important role in the scientific inquiry. Hence, both positions provide different and legitimate views on scientific practice that justify pluralism as the framework in which science should be carried out.