In a previous lecture we looked at Kuhn’s idea of history of science as broken by different paradigms that are incommensurable and which 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 you life.
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). 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 phenomena 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 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.
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. 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 they 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.
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.
 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.
 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.
 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)