Realism and Anti-Realism in the Philosophy of Science – Lecture 6

December 23, 2013

SpaceIn 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.[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 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.[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 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.

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.

[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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Spinoza: What is Substance? – Lecture 5

December 18, 2013

SpinozaPerhaps one of of the greatest obstacles to modern readers of Spinoza’s Ethics is the language he uses. It is one which would be perhaps understandable to readers of his time, but has become pretty meaningless to us now. It is a language that has its roots in greatest obstacles to modern readers of Spinoza scholasticism, though, like Descartes, (who is the most important philosophical influence on Spinoza) everything he writes is a rejection of this tradition. Scholasticism obtains its language from Aristotle (or at least as he is handed down by the Islamic scholars to the West in the 9th century), so we first need to go back to this source.

Those of you who have done a basic cause in Greek philosophy might remember Aristotle’s philosophy and especially his notion of ‘substance’, and this is where we need to start, since ‘substance’ in one of the most important words in Spinoza’s vocabulary. We are also going to use as our guide here the excellent book by Woolhouse, The Concept of Substance in Seventeenth Century Metaphysics.[1]

When we normally think of the word ‘substance’ in English, we associate it with the idea of matter. As for example, when we think of the question ‘what substance is this table made out of?’, we would probably respond by saying, ‘wood’ or ‘plastic’, corresponding to the material it was constructed from. This is not what Aristotle means by substance at all, and certainly not what Spinoza means by it. In fact Aristotle has a completely different word for matter in Greek, which is hyle. The word in Greek for substance is, on the contrary, ousia. Ousia is the 3rd person singular feminine present participle of the Greek verb ‘being’. Now the grammar of this word is not particularly important for us, but what is important is that it has its origin in the verb ‘being’. Ousia is not the word for matter for Aristotle but for what is. Everything that is, is named by the word ousia, since everything that is must necessarily be; that is, must necessarily possess being, whether we’re talking about tables, galaxies or even ourselves. This notion of being, Aristotle says in the Metaphysics, is the proper subject matter of philosophy, and no other study. So the question we must ask ourselves is what did Aristotle think was the answer to the question what is being?

What is real for Aristotle are individual things like men, animals and plants and so on, and what is, is made up of these individual things. This seems to follow common sense, and it is clear those philosophers before Aristotle where not so ready to agree with common sense. Many of them tended to believe that there was a much greater reality behind the individual things we experience, which it is the task of philosophers to describe. Think, for example of the first Greek philosopher that we have any information about, Thales, who thought that every individual thing was in fact made of water, which was therefore the ultimate explanation and reality of the universe.

The best way to understand Aristotle’s idea of substance is to go back to his theory of predication. In fact we might say that it is this theory of predication which is the true source of his understanding of being: the way we understand being has its origin in the way we talk about the world. A substance for Aristotle is a subject of a predicate, but which at the same time is not a predicate of anything else. This is true definition of what we mean by an individual thing: it is independent of anything else. This notion of independence, as we shall see, is crucial to the meaning of substance, and is the key especially of understanding Spinoza’s use of the word. A substance is what undergoes change (it can have different predicates attached to it), but it itself remains the same, or holds onto its identity. Think of Socrates the man. He can be young or old, cold or warm, wise and ignorant, and so on. We can predicate all these different and opposite predicates of Socrates, but nonetheless it is still Socrates the individual (who is different from Peter and the chair over there) who we say these things of. Substance, then, has two very important parts of its definition: independence, and identity.

Now the question for Aristotle, as it is for every philosopher, is whether individual things are the ultimate substance or whether there is something greater than individual things, and which can explain them in a better way than they can explain themselves. This would mean that individual things would not be independent but would be dependent on something higher. In the same way that hot only makes sense predicated on some other individual thing, and can only have a meaning because of this; individual things would be, in fact, predicates of something else. This would mean, therefore, that their ‘substantialness’, in the Aristotelian sense of the word, would be an illusion. But it is precisely this kind of thinking he rejects. What is real are individual things, and it is they that undergo change and not something else. We tend to think there is some more ultimate reality because like Plato we confuse the definition of something with its reality – thus, because we notice there is something common between different horses, we make the mistake of thinking that there is some kind of ‘Horse’ which is the ultimate cause of them. Or we confuse substance with matter; that is to say, we think everything is the same because they are all made of the same kind of stuff.[2] It is true that things are made of matter, and there might be some ultimate matter which is the explanation of all forms of matter (like atoms), but that is not enough to explain what something is for Aristotle. For Aristotle what something is made up of its matter and its form, and it is this form which is explained by substance. The form, therefore, tells us what the thing is and why it is what it is. Matter, alone, for Aristotle, cannot do this, for it just tells what is the same about everything, but not why this thing is the thing that it is and not any other.

The most important influence, as we have already indicated, on Spinoza is Descartes, who will use this Aristotelian vocabulary, but will give it a very different meaning. The two important characteristics, however, remain: independence and identity. Descartes writes as though he has escaped Scholastic philosophy, which has been the dead hand on scientific progress by retaining the Aristotelian view of nature, against the new mechanistic theory of nature. But this is just propaganda, for he will still use their vocabulary, and in relation to the idea of God, there is much that is ‘scholastic’ in his thought. The most important influence is the very idea of God itself. For this is not something that would have been of concern for Aristotle, at least not as it is presented in theological thought. For Aristotle the universe is eternal, but for the Christian thinkers, such a view would deny creation; an idea which would have been utterly inconceivable to Aristotle. The idea of creation changes everything in the doctrine of substance, for the notion of independence belongs to its definition. If the universe is created by God, and it must be in Christianity, then everything that exists in creation must be dependent on Him. There, therefore, can only be one independent substance, which is God. Descartes, however, is not willing to go this far. Rather, he says, we can distinguish between two kinds of substance: infinite substance, which is God, and created substance, which is any individual thing which is dependent on God for its existence, but not anything else. We could say they have relative independence, and they correspond to what Aristotle defines as substance. A substance, just as in Aristotle, is everything which is conceived of through itself and not through some other kind of thing, and that which exists (apart from the fact that it is created) in its own right. A substance is therefore the subject of predication, of which we predicate qualities, properties and attributes to, and remains identical through change.

We say that created substance is similar to Aristotle’s notion of substance. It is similar in its definition (independence and identity), but not similar in what it describes. For substance describes individual things in Aristotle, tree, galaxies and you and me, but it does not do so for Descartes. To understand this difference, we are going to have to look at two other technical expressions, which are also fundamental for Spinoza: attributes and modes. Descartes’ philosophical system has three levels of reality: infinite substance, finite or created substance, and properties or qualities. We could see the relation between these levels as one of dependence: with infinite substance, created substance would not exist, and without created substance properties and qualities could not exist, for they always need to be properties or qualities of something. These properties or qualities of created substance Descartes calls modes. If modes are dependent on substance, then substance in itself cannot be a mode. We know substances, therefore, for Descartes through attributes, and there are two main attributes which explain all the possible modes that we know: extension and thought. The first explains objects in the world, and the second thoughts in our heads. These two are quite different, and this is why they are to be explained through two very different attributes, which cannot explain each other. A thought is not an object, and an object is not a thought. Attributes, therefore, have something in common with substances: they can only be conceived through themselves and not through something else – thus we can only understand the attribute extension through extension (length, breadth and shape – which can be understood mathematically) and not through anything else, whereas a mode must be understood through extension (heat is the motion of particles). In the same way a thought can only be understood through the attribute thought, and not through anything else, whereas any mode of thought (belief, love, desire and so on) must be understood through thought, since one cannot desire something, for example, which one cannot think. These principal attributes constitute the nature of substance for Descartes, and there must, therefore, be two kinds of substances, which explains his dualist metaphysics. Thus, whatever exists, substance, attribute, mode, must either be a body or thought, and cannot be anything else. He does not give a reason why there is only two kinds of substance, but only that there are only two. Or if you like, God was free to create two kinds of finite substance, but he could have created more of different kinds.

How then is Descartes different from Aristotle? In terms of nature, the notion of individual substances disappears, such as trees, galaxies and human beings called Socrates. Rather, there is only one corporeal substance, of which these things are only modes. Thus, Descartes gets rid of Aristotle’s notion of forms, which explains why each thing is what it is. For Descartes this can be explained by the location, motion and rest of matter itself, and no appeal to any form is required. Individual human minds are, however, for Descartes, individual substances in the way that Aristotle would still talk of them. Anyone who thinks is an individual thinker, and cannot be the same as any other individual thinker – we do not have the same thoughts (this follows the rule that any substance must be independent). So for Descartes it is my mind or soul that individualizes me and not my body.

How, then, does Spinoza’s thought fit within these two descriptions of substance by Aristotle and Descartes? First of all, it follows the same definition of substance that it must be conceived in and through itself. Again this is what is meant by saying that substance must be independent. Also his notion of attribute appears to be the same as Descartes, in that it expresses the way that we perceive substance. We might ask ourselves, therefore, how an attribute comes to express substance. Why this attribute and not any other, for example? We have already seen that Descartes just says that there are two, but not why there are only two. Attributes are ways through which substance is understood. Now we really need to take care with our propositions here. For though Spinoza will agree that it is through attributes that we understand substance, he will argue further that substance is not only conceived through itself, but also in itself. What is the difference between conceiving substance through itself and in itself? Descartes collapses the real distinction between finite substance and its attributes (whilst making the latter dependent on God who is separate and transcendent) and this is why he can only conceive of two principal attributes. But for Spinoza, thought and extension are only the way that we perceive substance, but it in itself must have infinite attributes, since it must be infinite.[3] If it were finite, then it would be limited by something outside of itself, and therefore it will fail the test of independence which is the definition of substance. There must, therefore, be only one substance, and not two kinds of substances, as Descartes argues. If can only do so because he holds onto the difference between creation and God, finite and infinite substance. For Spinoza, on the contrary, there is only one substance which is ‘God or Nature’. We will need to describe the essence of this substance in the next lecture.


[1] ‘Descartes and Substance’ in R. S Woolhouse, The Concept of Substance in Seventeenth Century Metaphysics. London, Routledge, 1993, 14-27.

[2] Later on it will be important to see whether Spinoza is doing this, and whether substance means matter for him, for it is clear that unlike Aristotle he thinks that there is only one substance.

[3] This does not mean that thought and extension is merely the appearance of substance, which is something different in itself. They are real distinctions.


Kuhn and Scientific Revolutions – Lecture 5

December 17, 2013

Science 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.

The first philosopher 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.

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 psychology and sociology 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 different elements, some of which will be psychological and sociological. As more and more scientists come on board, what is in the 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 psychological and sociological. 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.

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.