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Philosophy of science

‘...the strength of the thread does not reside in the fact that some one fibre runs through its whole length, but in the overlapping of many fibres’ – Ludwig Wittgenstein. Photo by Getty

Getting it right


Michela Massimi


Michela Massimi


5,300 words

Edited by Sam Haselby

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Comte’s positivism was soon decontextualised from its political and social context (after all, Comte started his career working for the social theorist Henri de Saint-Simon, and positivism was inspired by the Industrial Revolution). By the end of the 19th century (and in its early 20th-century reappearance, which I do not have the space to discuss here), the word ‘positivism’ had become – to the ears of many – synonymous with an unfailing optimism in the power of science and technology, and their steady progress toward truth.

In some scientific quarters, this Comtean notion of how science evolves and progresses remains common currency. But philosophers of science, over the past half-century, have turned against the representation of science as a ceaseless forward march toward truth. It is just not how science works, how it moves through history. It flies in the face of the wonderful and subtle historical nuances of how scientific revolutions have in fact occurred. It does not accommodate how some of the greatest scientific minds held dearly to some false beliefs. It wilfully ignores the many voices, disagreements and controversies through which scientific knowledge has often advanced and progressed over time. Simple faith in the ‘Whiggish’ narrative of science naively presumes that progress is marked by some cumulative acquisition of ‘more true beliefs’.




A positive answer to the first question defines the philosophical stance known as ‘scientific realism’. Scientific realists maintain that the best scientific theories aim at truth as their final goal. But Van Fraassen pointed out (following the French philosopher Pierre Duhem), that often in science truth is not needed, and ‘saving the phenomena’ (or appearances) suffices. For example, Ptolemy’s astronomy could account for the appearance of planets moving in loops in the sky over months. This was called ‘retrograde motion’, and Ptolemy’s theory accommodated it by introducing a series of geometrical contrivances (epicycles and deferents) around which planets were supposed to move. In fact, there are no such circles of circles, and retrograde motion is just an illusion caused by the relative speeds of planets all orbiting the Sun. As Copernican astronomy realised several centuries later, Ptolemaic astronomy was false, despite its century-long success at ‘saving the observable phenomena’.

There are philosophers today who embrace the view that science does not need to be true in order to be good. They argue that asking for truth is risky because it commits one to believing in things (be it epicycles, phlogiston, ether or something else) that might prove false in the future. In their view, ‘empirically adequate’ theories, theories that ‘save the observable phenomena’, are good enough for science. For example, one might take the Standard Model in high-energy physics not as aiming at the truth about whether the world is really carved up into quarks, leptons and force carriers; whether these entities really have the properties that the Standard Model says they have; and so on. A more prudent approach aims for empirical adequacy. Insofar as the Standard Model saves all the observable phenomena (which are not about invisible particles, of course, but about macroscopic observable situations that we can see with our naked eye), the model is empirically adequate. Why ask for more?

When it comes to the second question – does science tell us the truth? – scientific realists and anti-realists of various stripes have debated it. Leaving aside the aim of science, let us concentrate on its track record instead. Has science told us the truth? Looking at the history of science, does it amount to a persuasive story of truth accumulated over the centuries? Philosophers, historians, sociologists and science-studies scholars have all challenged a simple affirmative answer to this question. They have in particular challenged the notion of factual truth implicit in the question. In this debate, philosophers take a well-defined set of facts about nature as responsible for making scientific claims true or false, and scientific progress consists in unveiling more of these facts until they are all finally revealed.

A crisp illustration of the view can be found in the Tractatus Logico-Philosophicus (1922), where Ludwig Wittgenstein right at the outset announced: ‘The world is the totality of facts’; and ‘the totality of facts determines both what is the case, and also all that is not the case’. Wittgenstein gave a deceptively simple view of how language maps on to reality and, more importantly, on to what he called ‘atomic facts’. For decades (without taking Wittgenstein as a direct target nor as an interlocutor in this specific debate on science), anti-realist trends in philosophy of science have called into question both the possibility of atomic facts and their ability to make scientific claims true or false. Many think these apparently simple matters face some formidable challenges.

This decades-long, multi-pronged, disenchantment-with-truth trend in philosophy of science starts by rejecting the idea that there are facts about nature that make our scientific claims true or false. Fact-constructivism is only one aspect of this multi-pronged disenchantment-with-truth trend. Outlandish as this might sound, its defenders claim that there is not a single, objective way that the world is; there are rather many different and ‘equally true descriptions of the world, and their truth is the only standard of their faithfulness’, in the words of the philosopher Nelson Goodman. For example, he claimed that we do make facts, but not like, say, a baker makes bread, or a sculptor makes a statue. In Goodman’s view, we make facts any time we construct what he called a ‘version’ of the world (via works of art, of music, of poetry, or of science). For example, Camille Saint-Saëns created a version of the world by composing his violin sonata no 1 in D minor, which in turn inspired Marcel Proust to imagine the Vinteuil sonata in the first volume of his novel À la Recherche du Temps Perdu (1913-27). Anyone who has read Proust cannot help thinking about the love story of Odette and Swann unfolding in the Verdurin salon when they hear Saint-Saëns’s mesmerising violin sonata.

Some argue that science does not tell the truth but does provide important non-factive understanding

Another way of constructing a version of the world is by clustering objects according to a particular shape and giving them a name. We do this all the time, for example, with stars and constellations. As the philosopher Hilary Putnam expresses it: ‘Nowadays, there is a Big Dipper up there in the sky, and we, so to speak, “put” a Big Dipper up there in the sky by constructing that version.’ Goodman’s world-making view has severe implications for truth in science. ‘Truth,’ he wrote, ‘far from being a solemn and severe master, is a docile and obedient servant. The scientist who supposes that he is single-mindedly dedicated to the search for truth deceives himself … He as much decrees as discovers the laws he sets forth, as much designs as discerns the patterns he delineates.’ Goodman’s view is similar in some relevant respects to the French philosopher Bruno Latour’s. In Pandora’s Hope (1999), Latour argues that facts about whether or not the savannah is advancing (and the Amazon forest retreating) are the outcome of laboratory practices about sampling soil, rather than independent facts about nature itself.






We see the spirit of Kuhn’s warning in discussions today. Truth itself is not enough to settle or even guide debates about expertise, trust, consensus and dissent in science. The philosophers of science Inmaculada de Melo-Martín and Kristen Intemann have described the matter well in their book The Fight Against Doubt (2018). When it comes to the role of science in policymaking, the key is ‘engaging in discussions with all relevant parties about the values at stake, rather than the truth of particular scientific claims’. Policymaking involves politics and values, and ‘disagreement about values cannot, and should not, be decided by scientists alone’ or by just scientific evidence. Intemann and de Melo-Martín have further maintained that, even if truth were the goal of science, consensus in a disciplinary or subfield community cannot always be ‘a proxy for truth, and whether it is necessary for adopting public policy is still questionable’.

To summarise, the history of science, the practice of science, and science policy all provide reasons for disenchantment with truth in science. That is why, in our time, philosophers of science who call themselves realists tend to add some qualifying adjective to the word ‘realism’ (be it ‘structural’, ‘selective’, ‘pragmatic’, ‘perspectival’ or ‘local’). The net result – the dethroning of truth – has left philosophical discussions about its nature to logicians, philosophers of language and metaphysicians, as opposed to philosophers of science.


While critical analyses of factual truth are indeed best left to logicians and metaphysicians, philosophers of science should not abdicate their responsibility to talk about truth in science. The quasi-Wittgensteinian myth of atomic facts as the truth-makers of scientific claims has proved inadequate to even scratch the surface of very complex practices in science. But that is not a good reason (or pretext) for forgoing truth altogether. Nor is it a reason for concluding that science should not be expected to tell us the truth. Philosophers of science have a social responsibility to talk about truth in science. Questions about truth cannot be left unspoken, delegated, or, worse, met with discontent and misgivings. For a serious engagement with the topic of truth in science – thorny and difficult as it might be – must be the starting point of any serious engagement with science in democratic, tolerant and pluralistic societies.

But whose truth? By whose lights? Some might be tempted at this point by a Jamesian pragmatist theory of truth. American pragmatism has traditionally provided an alternative way of thinking about truth, which some philosophers of science see as more congenial to capturing the complex nuances and the power structure of scientific practice. There are significant and important differences among pragmatists such as John Dewey, William James and Charles Sanders Peirce when it comes to truth (see Cheryl Misak’s Aeon Idea for an excellent introduction), and one should avoid assimilating or caricaturing this diverse and nuanced range of philosophical views. In James’s words: ‘“The true” … is only the expedient in the way of our thinking, just as “the right” is only the expedient in the way of our behaving.’ Stripped of its rhetorical flourishes, for James to be true is (to a good approximation) to work successfully. A scientific model is true – on a loosely Jamesian view – if it successfully facilitates and enables activities (be they epistemic or not). If the billiard-ball model of Brownian motion helps scientists to predict the behaviour of gas molecules, for example, the model is (pragmatically) true. The falseness of the presumption of perfectly spherical molecules does not matter. Is the Jamesian conception of truth more congenial to science, and more conducive to pluralism in democratic societies?



Truth is a normative commitment inherent in scientific knowledge

Thus, in physics, one can speak of the Newtonian perspective vs the Einsteinian perspective; in chemistry, the Priestley vs Lavoisier perspective; in economics, the Keynesian vs the monetarist perspective; or the classical-genetics vs molecular-genetics perspective in biology, and so forth. What is to be said about the flourishing array of scientific perspectives? One thing is certain: science works through producing a plurality of perspectives. Over time, it leads to scientific progress, a process Comte mistakenly theorised into a monist picture of ‘positive science’. But a plurality of scientific perspectives does not solve the problem of truth. On the contrary, it invites worrisome thoughts that truth is either redundant to scientific perspectives; or, worse, relativised to perspectives. One might ask again: whose truth? By whose lights?



Constructive empiricists, instrumentalists, Jamesian pragmatists, relativists and constructivists do not share the same commitment. They do not share with the realist a suitable notion of ‘rightness’. As an example, compare the normative commitment to get things right with the view of the philosopher Richard Rorty, in whose hands Putnam’s truth as ‘idealised warranted assertibilityreduces to what is acceptable to ‘us as we should like to be … us educated, sophisticated, tolerant, wet liberals, the people who are always willing to hear the other side, to think out all the implications’. Getting things right is not a norm about us at our best, ‘educated, sophisticated, tolerant, wet liberals’. It is a norm inherent in scientific knowledge. To claim to know something in science (or about a scientific topic or domain) is to claim for the truth of the relevant beliefs about that topic or domain. But, a critic might reply, how can our knowledge – which is perspectival, entrenched in historically and culturally well-defined scientific practices – track the way the world is? How can we be expected to truthfully believe the things we believe in science, despite being situated in a plurality of scientific perspectives? To put it in a different way, how can we – historically and culturally situated epistemic agents – reliably build scientific knowledge over time, despite the possible errors and false steps of past (and current) scientific perspectives?


Since the 16th century, the method of science has been at the centre of an important debate. The hope was that a method (if any could be identified) could lead to conclusions that ought to be shared, communicated, agreed upon. But we learned that there is no single scientific method, some magic recipe valid always and everywhere, across disciplines. A plurality of scientific perspectives is not however a royal road to some worrisome kind of perspectival solipsism, thanks to the normative realist commitment that scientific perspectives ought to (and typically do) share.

Scientists endorsing different scientific perspectives (and I stress the adjective scientific here to undercut a possible rejoinder that might trade on the ambiguity of the word ‘perspective’) do not construct perspectival facts. To do so would be to possibly commit scientific fraud. Rather, they ought to share a commitment to the same tribunal of evidence. They might adopt different experimental strategies, different models, different theories. They might endorse different values about what really matters in a given field. But it is the tribunal of evidence that they all ultimately ought to respond to. Getting the evidence right, in the first instance – via accurate measurements, sound non-ad-hoc procedures, and robust inferential strategies – defines any research programme that is worth being called ‘scientific’. The realist commitment to get things right must begin with getting the evidence right. No perspective worthy of being called ‘scientific’ survives fudging the evidence, massaging or altering the data or discarding evidence.

Scientists endorsing different scientific perspectives do not concoct the scientific standards by which their knowledge claims, and their resilience over time, are assessed. To do so would run the risk of partiality, or ad-hoc manoeuvring. Obviously, the notion of ‘scientific standard’ is complex and one has to tread carefully. Nonetheless, by and large (without any presumption of producing an exhaustive list), scientists ought to share a commitment to common scientific standards. They might disagree about what counts as a ‘simpler’ theory (eg, introducing new entities vs modifying laws of nature); they might place a different emphasis on the role of consistency vs explanatory power when it comes to modelling at different scales. But they ought to agree that any viable scientific theory must be able to make sense of the available evidence broadly along the lines of those (among many other possible) scientific standards.

Truth is not a commodity disposable with the old scientific paradigm

Scientists ought to share rules for cross-perspectival assessment. That our knowledge is situated and perspectival does not make scientific truths relativised to perspectives. Often enough, scientific perspectives themselves provide the rules for cross-perspectival assessment. Those rules can be as simple as translating the 10 degree Celsius temperature in Edinburgh today into the 50 degree equivalent on the Fahrenheit scale. Or they can be as complex as retrieving the viscosity of a fluid in statistical mechanics, where fluids are treated as statistical ensembles of a large number of discrete molecules. At other times, scientists might not necessarily possess a rule-book, so to speak, for ‘translating’ knowledge claims from one scientific perspective into another. In those situations, we need something like what Kuhn called ‘bilingualism’ (rather than translation).

Even in genuine scientific revolutions, when old taxonomies fall and new, previously undreamt ones, take their place, truth is not a commodity disposable with the old scientific paradigm. Critics of Kuhn – who emphasised continuities during periods of crises and scientific revolutions, and paid attention to the subtle nuances that scientific concepts undergo across centuries – have a point here. Namely, that it is our commitment to get things right across perspectives (indeed across major conceptual upheavals) that allows communities (before and after a revolution) to understand one another and to grow in their scientific knowledge – no matter how different and perspectival the local idioms in which their scientific claims might be couched.

Galileo, trying to escape the Inquisition, arrived at a new concept of gravitas that eventually advanced the new lexicon of Copernicanism against the backdrop of century-long criticisms of Aristotle’s theory of motion, elaborated by Jean Buridan and Nicole Oresme in 14th-century Paris, and before them by the Medieval Arabic commentators of Aristotle (the so-called Baghdad school, and Abu’l-Barakāt’s almost prescient study of accelerated motion). Lavoisier, a tragic victim of the French Revolution, knew how to use the old apothecary’s concept of weight to advance his critique of phlogiston theory and to usher in the new concept of oxygen and a new role for chemistry. Chinese knowledge about how to use saltpeter for making gunpowder entered Europe through the Silk Road and made possible Robert Boyle and Isaac Newton’s highly influential speculative experimentalism about ‘true permanent air’ being released in explosions, and an entire research programme for the study of fire and electricity in the British and Dutch natural philosophy of the 18th century (in addition to its use in pyrotechnic arts). And as Sandra Harding has argued in Objectivity and Diversity (2015), Micronesian knowledge about navigation systems has a lot to teach us today.


Communities of epistemic agents learn how to get things right across time, across historically and culturally situated scientific perspectives. Not because there are atomic facts as truth-makers of atomic propositions, but because the perspectival nature of our scientific knowledge resembles what Wittgenstein called the thread that ‘we twist fibre on fibre. And the strength of the thread resides not in the fact that some one fibre runs through its whole length, but in the overlapping of many fibres.’ Scientific truths are the resilient and robust outcome of a plurality of scientific perspectives that, over time, have meshed with one another in their (tacit, implicit and often survival-adaptive) normative commitment to reliably produce scientific knowledge for us as humankind. That is why, far from being an insufferable hindrance to scientific pluralism, truth is in fact its best safeguard in tolerant, open and democratic societies that are genuinely committed to the advancement of scientific knowledge in the very many faces it comes with.

Many thanks to Matthew Chrisman and Mark Sprevak for very helpful comments on earlier versions of this article. This article originates from a project that has received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (European Consolidator grant H2020-ERC-2014-CoG 647272, ‘Perspectival Realism: Science, Knowledge, and Truth from a Human Vantage Point’).

Michela Massimi

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