Realism and Anti-Realism in Science – Lecture 6

December 19, 2014

Stylised_Lithium_AtomIn a previous lecture we looked at Kuhn’s idea of history of science as broken by different paradigms that are incommensurable. Aristotelianism, Newtonianism, and Einsteinianism, mark revolutions in the history of science rather than a smooth flow of one epoch into another which will some day reach an ultimate Truth when we can all stop doing science because what our theories say and what is are exactly the same and there will be no exceptions. What Kuhn reminds us is that when we think about what science is, rather than taking the philosopher of science’s word for it, we should examine what scientists do. We will find that the philosophical version does not much look like the real history of science, rather they are idealisations in both sense of the word: an abstraction and a kind of wish fulfilment. Kuhn is not sceptical of science as such, but the philosophy of science. His book, The Structure of Scientific Revolutions, marks the death knell of a particular kind of philosophical history of science, so that it can be replaced by the proper history of science, whose object is what scientists actually do, rather than what philosophers think they might do. In other words, the new object of this history of science is ‘normal science’, in all its messiness and vagueness, rather than an idealised science that has never existed except in the minds of philosophers like Ayer or Popper.

At this point, however, we are going to make a little detour back to philosophy, and that is to the question which should have been bugging us from the very beginning, which is what exactly is science about, rather than what is the history of science. Early on we characterised the difference between religion and science as the difference between belief and facts. We said that science is about reality, that it makes true description of real things that happen in the world. In a word, it is objective. On the contrary, religion is subjective. It does not give us a true picture of the world, but offers us a moral compass through which we can live our lives. To confuse religion with science is to undermine the importance of religion rather than to give it more intellectual support. There is no conflict between science and religion, because they are completely different discourses. One tells you what something is, the other how you ought to live your life.[1]

But what do mean when we say that science is about reality? Aren’t we being a little simplistic when we do that? What is reality after all? Everyone knows the old paradox of whether a tree that falls down in a forest makes a sound or not if no one is there to hear it. Is reality what we perceive or is it more than that? I would say that it would be absurd to say that there would not be trees, stones or stars if there were no human beings. As though human beings were to vanish the universe would vanish with them. The universe does not have any meaning, however, except for the fact that it means something for some being or other in the universe. A stone is not a stone for a stone. It is only a stone for human beings who understand what it is to be a stone. We’ll come back to this at the end of the lecture.

Both Chalmers , Okasha, and Ladyman (perhaps because they all belong to what can be loosely called the analytic tradition) seem very reluctant to address these questions head on (as though they were too philosophical and could be avoided. I would say that it is their hidden philosophical assumptions which allow them to avoid these questions).[2] For them, on the contrary, the important distinction is between realism and anti-realism, rather than whether reality exists out there as such and what we might mean by reality as a whole. Chalmers simply dismisses the idea that reality being formed by language (what he calls global anti-realism), through a Tarskian theory of truth, which begs the questions, because such a theory already has a commitment to a certain view of language, and a certain view of reality, which remains unquestioned by Chalmers himself. Investigating this presupposition, however, would take us too far from the subject of this lecture itself.

What then is anti-realism and realism in science? First of all it is important to note that both theories accept the reality of the world. So it is important not to confuse either with a thorough going scepticism. The difference between them has to do with the status of scientific theories, on the one hand, and observable phenomenon on the other. A strong realist would argue that both observable phenomenon and theories are true descriptions of the world out there, whereas an strong anti-realist would say that only observable phenomenon are true, and theories are neither true of false. All these authors, as far as I can see, occupy a position between these two extremes.

The common sense view, I suppose, would take it that both theories and observable phenomenon are true, so we are going to approach this question from this point of view. None of us would think that observable phenomenon are not real, that when I see a donkey there isn’t a donkey out there (again I am not so sure that both Okasha and Chalmers skip over this supposed reality far too quickly, but let us leave them to have that truth for now). What isn’t so certain is that theories really point to something out there. This is because much of the basis of a scientific theories actually point to phenomenon that we cannot observe. If we cannot see something, then how can we say that it is part of the world? From what vantage point would we say that it is real? Of course, as Okasha points out, many sciences do have as their basis observable phenomenon, such as palaeontology whose objects are fossils, but modern physics does not (Okasha, 2002: 59). We cannot literally see inside of the atom. We only have theoretical pictures of what they look like, and we do not know if at that level the universe really looks like that at all.

The anti-realist is not saying that there is no difference between science and someone who thinks that the earth is balance on the back of a turtle. Rather theories only give us structures or the scaffolding in which we can observe phenomena through experimentation, but it is only this literally observable phenomenon which we can take to be true. The theory itself we cannot prove is real or not, because there is nothing there to see which we could demonstrate as real or not. The history of science itself seems to bear this out, because there have been false theories that have actually brought out true observable phenomena, so there does not seem to be an analogy between the truth of a theory and the truth of observable phenomena. The example that Chalmers gives is the history of optics, which is littered with what we now understand to be false theories of light, and yet which provided correct observable phenomena. Thus Newton believed that light was made up of particles, then Fresnel believed that light was a wave in a medium called ether, then Maxwell, believed that light waves were fluctuating electric and magnetic fields in ether, then in 20th century we got rid of the ether and the waves were entities in their own right, then finally the wave theory of light was supplemented by the particle theory of photons.

It seems to go against common sense, however, to say that theories are just fictions on which we hang our experimental results. When we look at the history of atomic theory it does appear that we are getting a progressive understanding of the structure of atom, and it would seem entirely bizarre that the theory would predict what we ought to see, and at the same time being entirely false. One way of getting around this is by arguing that the anti-realist is making a false distinction between what is observable and what is not observable, since though we cannot see inside the atom, we can detect the existence of atoms by ionisation when they are passed through a cloud chamber. The strict anti-realist, however would say that, all we know is real is the trails themselves, and we cannot not know whether the atoms are real or not, just as we should confuse the trail that a plane leaves in the sky with the plane itself. In other words, we have to make a distinction between direction observation and detection.

The fundamental issue here is whether we can make a complete separation between theories, on the one side, and facts on the other. This is the real issue, rather than whether facts are observable and theories not. In fact it is the anti-realist and not the realist who is committed to the separation. Both Okasha and Chalmers, though in different ways, would criticise this separation. Chalmers returns to whether the history of philosophy really does prove that theories which were once taken as true are shown to be false by the next one, and so on infinitum, so that we can never know whether are theories give us an accurate view of the world, by arguing that each new theory takes up some aspect of the previous one which gives us a more and more accurate picture of the phenomenon we are attempting to understand. Thus a true theory (unlike the turtle theory) captures some aspect of the truth of the world, if only a partial one, which is then improved by the subsequent one (does this conflict with the Kuhnian view of science, since it implies an accumulative image of science?). Okasha, on the other hand, will claim that the problems that the anti-realist claims would undermine the possibility of claiming theories to be true, could also rebound against what we would think were observable phenomena, and thus would destroy the basis of all science altogether, since we could only claim to know what we could see now in this moment, and not past events, since again they are only known by detection rather than direct observation (this would be mean that the anti-realist argument would be like Hume’s problem of induction).

As I said at the beginning, I find both Okasha’s and Chalmers discussion of realism unsatisfactory and indeed both of their chapters seems to end without any kind of resolution as though they had both been exhausted by the discussion. What I think is left unthought in their views is that the only way we could access reality is through science, and thus if we cannot, then we cannot access reality. To me the discussion of observable and unobservable phenomena is a red herring. Nothing has meaning unless it has meaning for us and that is true of both observable and unobservable phenomena, but the real issue is whether our reality is first of all something that we observe. Here I would turn to the philosophy of Heidegger, who would argue that it is prejudice of a very old metaphysics that our first relation to the world is one of perception, what he calls ‘present-to-hand’. What is true both for the realist and the anti-realist is that they take reality to mean ‘present to hand’. It is just that one thinks scientific theories are speaking about something present to hand and the other does not. The world for Heidegger, on the contrary is not something, present to hand, but ready to hand. The world is first of all something that we orientate ourselves in, rather than perceive.[3] This context can never be investigated as an object, because it is what objects make possible. Even science itself must have its origin in this cultural context or background. It is only because science as an activity means something to us that we can approach anything in the world as a scientific object, and not the other way around.

As Heidegger argues in Being and Time, Newton’s laws are only true because we exist. If we were no longer to exist, and the world in which these laws made sense were no longer to exist, then it would be absurd to still say that these laws were true. This does not mean that things do not exist separate from us, nor that truth is relative. Newton’s laws really say something about things, because these things only are, in the sense of ‘true’, through our existence. This truth would only be relative if we really thought that there was a truth of things beyond our existence that we did not know. Things are only because they are there for us, but this in no way means that any assertion is possible. This would be to confuse assertion and the condition of assertion. The truth of reality is dependent on our existence, but this does not mean that you or I can say anything we like about this existence. For you or I as individuals are just as much part of this existence as anything else is. To be a scientist is to already except what this existence means (what the world of science means, of which Newton’s laws are an example), and to refuse this is no longer to be a scientist.

Works Cited

Van Fraassen, B. (2006). Weyl’s Paradox: The Distance between Structure and Perspective. In A. Berg-Hildebrand, & C. Shum (Eds.), Bas C. Van Fraassen: The Fortunes of Empiricism (pp. 13-34). Frankfurt: Ontos Verlag.


[1] It is a wholly other topic whether religion is the only discourse that can do this, but that does not undermine our distinction between it and science.

[2] Okasha, Samir, ‘Realism and Anti-Realism’ in Philosophy of Science: A Very Short Introduction, Oxford: OUP, 2002, 58-76. A. F. Chalmers, ‘Realism and Anti-Realism’ in What is this Thing Called Science?, third edition, Maidenhead: Open University Press, 1999, 226-46.. Ladyman is more willing to discuss the philosophical issues in depth, but he does so from an analytic perspective. What is lacking in all these treatments is what I would call ‘ontological depth’, and I am going to turn to this in the next lecture which will look at some of the ideas of Heidegger.

[3] I think that this is what Fraassen is getting at when he says that a theory or model of reality is only useful when we locate ourselves within it, though I don’t think he is referring to Heidegger’s distinction here. (Van Fraassen, 2006, p. 31)

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Kuhn – Lecture 5

December 13, 2014

JastrowDuckRabbitScience does not begin with facts and then construct theories out of them. Nor does science begin with theories and then just find facts that would confirm them. Both these conceptions conceive of science as though it were a discourse that was completely context free. In the first case, facts are simply available as though they were waiting for interpretation of a specific kind, and in the second case, theories are simply open to facts as though there were no inertia or hindrance to the smooth progress of science from one theory to the next, each equally open to the possibility of falsification.

One of the first philosophers of science in the Anglo-American tradition to take the idea of context or background to scientific activity seriously was Thomas Kuhn.[1] Loosely characterised this approach might be called ‘historical’. What does it mean to treat science as though it were part of history rather than outside of it? It means first of all to take scientists seriously. It is to treat what they do the same way that we would analyse the thoughts and actions of French peasants or the 13th century or a military general in the 20th. First of all to record scientific achievements correctly (who thought of what at what time), and secondly to examine exactly how scientists come up with their theories in relation to the material they were investigating. What it certainly is not is the importation of philosophical theories from the outside (like verification or falsification) followed by squeezing the scientific activity to see whether it would fit these ideal models.

However much the logical positivists and Popper might differ, they both have the same idealised view of science: there is a sharp difference between theory and observation; knowledge is cumulative tending towards a true understanding of the universe; the language of science is precise and science is unified; science is either inductive or deductive; the key question of the philosophy of science is legitimacy and validity, rather than the contingency of discovery. Against all the suppositions Kuhn puts forward exactly the opposite: there is no sharp difference between observation and theory; knowledge is discontinuous; science is neither a tight deductive structure nor an inductive reading of facts; scientific concepts are not precise; nor is science unified; context is important and science is historical and temporal.

At the heart of the idealised picture of science is scientific progress. This is the view that science is leading to ever increasing knowledge about the universe and that finally one day we will have a theory of everything, and I suppose, science can come to end, because there will be no more questions that need to be answered. So first of all there are pre-scientific theories of the universe that we find in the religious and mythical texts (like Genesis), and then we get the first science, Aristotelianism (though this is a really a mixture of science and occult explanations), then Newtonism (which is the first science proper) and then finally in our times, Einsteinian science which is a response to the crisis that befell Newtonism. One imagines that sometime in the future, though one can never tell, there will be fourth science that will replace Einstein, but only because it contains more truth and is close to the universe as it really is than all the other theories that we have had. Such a view of the history of science, we might call ‘convergence’, since it views the series of scientific discoveries of converging on the true understanding of reality.

There are two problems with this image of science. One is temporal and the practical. First of all it has a conception of time, where the past is merely a stepping stone to the present but the past has no meaning in itself. For how can we measure the progress of science in this sense unless we imagine an end towards which it is moving and this end is supposed to be an advance on the past?[2] But how can we know that this advance is real unless we can stand outside of time and measure it? Is it not really the case that past is not the stepping stone to the future, but that we judge the past from the vantage point of the present, and in looking back, project a false teleology back into the past? In terms of the past itself, there were numerous possibilities and the present that we now occupy did not have to occur. Equally the present that we now stand in has infinite possibilities, so we cannot know what the future will be.

In terms of the practice of science, we also know that his temporal picture of progress is false. This is what Kuhn discovered when he did his own historical research. Rather than the history of science demonstrating that each scientific period progressed into the next one moving to ever greater level of truth and closing the distance between discourse and reality, we find that it is discontinuous and non-cumulative and that there is no reality out there, which we could know independently and through which we could measure the relative truths of each discourse because reality itself is a creation of discourse and not its external validation.

What does it mean to say that the history of science is discontinuous rather than continuous, non-cumulative rather than cumulative? Let’s go back to the image of progress where science moves smoothly from Aristotle, to Newton, to Einstein. What is left out in this description is the gaps or spaces between each scientific theory (or what Kuhn calls a paradigm, because it is more than just a theory) and it can leave this gaps out because the fantasy of some ultimate truth which is where reality and discourse are the same. As soon as we leave this fantasy behind, and realise that it too is a creation of a discourse (in this case metaphysics), then we can see that there is no transition of one to the other. Rather, they are separate or incommensurable. They belong to different worlds.

Again this is visible when we actually study the history of science, rather than project our own view of progress upon it. What we get instead of single continuous line is line of breaks: Aristotle, Newton and Einstein. What then causes these breaks? Why don’t we just go from one science to another in an endless progression towards the truth? The answer for Kuhn is to be found in history and not in the philosophical image of science as a universal method.

The new picture we have of science is now as follows: first we have pre-science – normal science – crisis or revolution – new normal science – new crisis (Chalmers 1999, p.108). When at first science begins to emerge we don’t have a collection of facts or theories that explain facts, rather we have a competition between many theories (Chalmers gives the example of the state of optics before Newton). Gradually different scientists will be attracted to the one explanation. What is important is that the reason for this attraction will not just be scientific or rarely just scientific. It will be a combination of difference elements some of which will be psychological, sociological and even metaphysical. As more and more scientists come on board, what is in a state of chaos will coagulate into a paradigm. Only at that point will normal science be possible (the kind of science that Popper and the logical positivists describe). But even a paradigm, which makes normal science possible, is not made up of merely theories and observations. Like Newtonian mechanics, it is constructed from fundamental laws and theoretical assumptions, standard techniques and methods of investigation, general rules about exceptions and application to reality and most importantly of all a kind of world view or metaphysics which will unify all of this together (in Newtonism, that we exist in an infinite deterministic universe).

Rather than anomalies, as Popper would have us believe, being antithetical to normal science, it can quite happily accept them as long as they don’t attack the fundamentals of the paradigm. Everyone can get happily to work devising their experiments and putting in their grants and anyone who goes against the status quo can be banished to the outer darkness. The paradigm is reinforced by the institutions themselves. If you don’t follow the paradigm you won’t get the grant money, and anyway the education of young scientists make sure that they follow the paradigm. This is clearly what Kuhn saw when he first looked into the history of science as a practicing scientist: young scientists were taught the idealised image of science that had nothing at all to do with the history of science at all.

So why do paradigms fall? Why are revolutions inevitable? This is because of the anomalies. Because no discourse can close the gap between itself and reality, there will always be the nagging doubt that something is not being explained by the paradigm. As more and more money and experiments are thrown at these anomalies, cracks begin to appear in the scientific establishment. Thus a normal science begins to take the form of the pre-science. Rather than scientists doing experiments, they start having ideas and hypothesis. Some might be said to be cranks and fools, but gradually they begin to attract other scientists. Again Kuhn is clear that the reason for this cannot be scientific or logical, because there is nothing in one paradigm that would justify the leap to another, for there is no commensurability that would link them together, such that one might say that one is truer than the other. The reasons are practical. As more and more are attracted to this new science, gradually a new paradigm is born and the whole process repeats itself. We get a new normal science, where again people can happily devise their experiments, apply for grants and get promotion. Until of course the cracks start appearing again.

Although this appears to be an accurate representation of what scientists do, there is a fundamental problem with it. If we are to give up the image of science as the progress towards a truth in which the distance between discourse and reality is progressive closed, for a discontinuous series of closed paradigms, then does this make scientific truth relative? We can distinguish normal science from pseudo-science because of how paradigms work (the difference between astronomy and astrology), but that does not make science itself any truer. Can we say that Einstein, for example is truer than Newton? We want to feel that this is the case, but Kuhn’s principle of incommensurability will not let us do so. The answer to this question, as we shall see when we read Kuhn’s The Structure of Scientific Revolutions in more detail, is that we might have to change what we mean by truth, rather than giving up truth altogether. It means that we have to think of truth as a practice or activity, rather than as a representation of a reality that stands outside of us waiting for our discourse to catch up with it.

Works Cited

Chalmers, A.F., 1999. What is this Thing Called Science?, St. Lucia, Qld.: University of Queensland.

Sharrock, W.W. & Read, R.J., 2002. Kuhn : Philosopher of Scientific Revolution, Cambridge: Polity.


[1] He might have been the first American philosopher to take this idea seriously. In France, this was the dominant view of science (Sharrock & Read 2002, p.1).

[2] It is science (think for example of evolution) itself that should make us suspect such teleological arguments.