Falsification HM5501 Lecture 4

October 15, 2017

Karl_PopperWhat we want is some criterion which will allow us to distinguish science from any other discourse. In other words what makes science, science, as opposed to religion? What is specific to the method of science? Our simplest response to this question is that science deals with facts that are objective (out there in some way) and that religion has to do with belief and is subjective. We might want to say, then, that science is true, and religion is not. When we looked at this simple definition, however, the less certain and clear it seemed. For the idea that science is made up of many observations of facts that are then converted into theories breaks down in the problem of induction, which, in its most succinct form, is the impossibility of leaping from a singular judgement to a universal one. No amount of logical finessing will get you from a particular to a universal judgement. This would seem to imply that science is no more objective than religion, and that a theory is as much a belief as any faith, though a particularly strong one when it comes to habits of the human mind.[1]

Moreover, it was also clear that the ‘inductionist’ picture of science was not accurate at all, since facts are not just littered throughout the world such that we pick them up and notice common characteristics from which we then construct some universal law, as though coming up with a scientific theory were no different from observing black crows and coming up with the statement ‘All crows are black’. On the contrary, we already come to facts with a pre-existing theory, which determines which facts we take as relevant or not (or even which fact we can see). As Ladyman explained, Newton did not find the law of gravity in Kepler’s data, he already had to have it in order to interpret the data (Ladyman 2002, pp.55–6).

This reversal of the relation between theory and facts, that theory is first and facts second, is the basis of the next philosophy of science that we shall look at, Popper’s theory of falsification, and indeed rose out of the insurmountable problems of ‘inductionism’. His argument is that we should give up induction as the basis of science, but such a rejection would not lead to irrationalism. Rather we substitute for induction, deduction. But did we not argue already in the first lecture that deduction could not be the basis of science, since deduction is merely tautological? Deductive logic tells us nothing new about the world, but only analyses what we already know, whereas science actually tells us something about nature that we didn’t know before.

Deduction does not work as a basis of science only if we move from the singular to the universal, but if we go from the universal back to the singular then deduction does work. Indeed, this move from the universal back to the singular is exactly, Popper argues, how science operates. We do not start with facts and then make laws, rather we start with laws and then we attempt to test them with facts. The logical point is that we can’t go from observations to theories, even if the observations themselves are true, but it is possible the other way around. We can go from theories then back to observational statements to show that the theory is false. Thus to use Chalmers example, if someone was to see a white raven outside the lecture room today, then this would prove deductively that the statement ‘All Ravens are black’ is false. Such deductive arguments are known as modus tollens, which take the form if P, then Q. ⌐Q, therefore ⌐P (Chalmers 1999, p.61).

When we look at the history of science, this seems exactly what happens. Take for the example, Eddington’s proof of Einstein’s theory that gravity bends light. If the theory was correct then a star that was beyond the sun should be displaced from the direction of the observer so that we could see it. Normally the light from the sun would mean that these starts would not be visible to us, but would be if the light of the sun was blocked. Eddington managed to measure just such a displacement with the eclipse of the sun in 1919. For Popper, the point of this story is that he could have proved otherwise. In other words, Einstein’s theory could have been falsified, if there had not been any displacement.

The real difference between science and religion or any other discourse is not the theories or hypotheses put forward, but how they are tested. Popper is adamant that science is creative as any other human discourse and that the origin of this creativity is outside any logical explanation. That someone comes up with such an idea at such a time cannot be logically deduced. Thus, it would require a complex explanation, comprising of psychology, history, and sociology, for example, of how Galileo or Einstein came up with their ideas, and why not someone else, or at different time and place, but what we do know that what makes these creations scientific, as opposed to anything else is that they can be falsified (this is the difference between context of discovery and context of justification). In the opposite case, it does not seem possible to falsify a religion logically. I can always find a reason to believe something. Think for example of the classic problem of evil in theology. How do I justify the existence of God with evil in the world? It is perfectly possible to find such a reason, as Leibniz did, that this is the ‘best of all possible worlds’, and it is just our lack of human understanding that prevents us from seeing it so.

Here we might need to know a little of the story of Popper’s life. When he was young he was a communist and of course Marxism was treated as a science. He says that one day in went on a march with his friends and they were attacked by the police and some of them were killed. He was so shaken by this incident that he had to speak about to his political leaders. They told him that these deaths were necessary for the political emancipation of the workers as was explained by scientific Marxism. But what then would falsify Marxism, for they did not seem to be any instance, including the death of his friends that could not be explained by it.[2]

This is precisely the difference between a science and a pseudo-science (religion is only a pseudo-science when it takes itself to be answering scientific questions, otherwise it is perfectly meaningful for Popper): a pseudo-science has the answer to everything and can never not be true, whereas a science does not have the answer to everything and can always be false. It is this that demarcates, to use Popper’s word, empirical science, from anything else, and it is a question of method, rather than logical form, by which he means the positivist obsession with the correlation of statements with aspects of reality. Metaphysics and religion are only pseudo sciences when they pretend to be sciences. If they do not, then there is nothing intrinsically wrong with them. They are certainly not meaningless which is just derogatory word, rather than having any useful philosophical sense.

If what makes a scientific theory scientific is falsification, what exactly makes a falsification? Can any falsification be scientific? Such a broad generalisation does not seem to be correct because just to falsify something would not make it a scientific theory. I could falsify physics, by quoting Genesis but no one would think I was being scientific. The answer here is intersubjective testability. One cannot conceive of how it would be possible to set up an experiment that would test my falsification of physics that claimed God had created the universe in the way that it is described in Genesis. One can imagine, however how it might be possible to test the falsification of Newtonian science through the prediction made by Einstein, which is entirely what the example from Eddington proves, and it is perfectly possible that other scientists could conceive of such an experiment, whether in principal or in practice.[3]

Could a theory always secure itself by simple adding an ad hoc modification every time a falsification was produced? Thus, to use Chalmers’s example, we could take the generalisation that all bread was nutritious to be falsified by the death of all the members of French village who ate bread. We could then qualify our theory by saying that all bread is nutritious except when it is eaten by these members of the French village and we could do this every time any falsification was discovered. Such ad hoc modification would destroy any progress in scientific discovery. How then can we distinguish between an authentic and inauthentic ad hoc modification (Chalmers 1999, p.75). In this example, the modification cannot be falsified, so it does not tell us anything new about the world. It in fact tells us less than the original theory that all bread nourishes. So, an authentic modification must be one that is also falsifiable. If we had said instead that all bread nourishes except one that is contaminated by certain fungus called Claviceps purpurea, then this would be an authentic ad hoc modification, since it could be tested and falsified, and thus does tell us something new about the world.

This distinction between authentic and inauthentic ad hoc modifications of scientific theories, however, tells us that we should not over-estimate falsifications of theories. When we look at the history of science we can see that ad hoc modifications can confirm rather than deny a theory. Take the case of the discovery of Neptune. Irregularities in the orbit of Uranus predicted that there must be another planet that had not be observed. Rather than reject Newton’s theory, scientists argued that a planet must exist that would explain it. Thus, the fact that Neptune was found in 1846 confirmed Newton’s theory rather than falsified it. Rather than seeing science as just a series of falsifications, which lead from theory to the next, Aristotle to Newton to Einstein, we should see it as the confirmation of bold conjectures and the falsification of cautious ones. For what difference does it make to science if one falsifies conjectures such as the universe is made of porridge or confirms a cautious one? But how then do we determine what makes a bold conjecture? The only answer to this must be background theories themselves, for only in relation to them could we know what would be bold or timid. The background knowledge is therefore the cautious conjecture (what we take to be correct) and the bold conjecture flies in the face of what everyone thinks is the case. We can see, then, what the real fundamental difference between the falsificationist and inductionist is. The first takes the history of science seriously, and the second has no conception of the history of science at all. There is no background knowledge. Rather facts are accumulated as though there were no context at all and science existed in the eternal present.

Is falsification immune to criticism then? The answer must be unfortunately not. The real problem is still the relation to the theory and the observation. All we can say deductively is that if there is O, then the falsity of T follows if the O is not given, but it tells us nothing about the standard of the evidence itself. What if the evidence is incorrect? Perhaps when person who said that the raven was white and no idea what white was. Perhaps the photograph of the white raven was created in Photoshop, and no such evidence exists. Popper does not have a better story about the correctness of evidence than the positivist.

Moreover, when we look at science, it does not take the simple form of ‘All swans are White’. Rather, sciences are made up of complex collection of universal statements which are interrelated to one another. Now if a prediction tells us the theory is false it tells is that one of the premises might be wrong but not which one or even that our own experience might be the problem. It might not the theory that is out, but the ‘test situation’ itself, because we cannot isolate the premise which allows us to falsify the theory (this is known as the Duhem/Quine thesis). So to use Ladyman’s example, if we were to try and predict the path of a comet, the law of gravity would not be sufficient, so if the predication were incorrect we would not know that it was the theory of gravity that was being falsified or something else (Ladyman 2002, pp.77–8). You cannot isolate hypotheses in science and refute one and others, because these different hypotheses fit together to make a whole.

Even if such an isolation were possible, falsification does not seem to capture what scientists do, for when we look at the history of science we do not find one great conjecture following another, but that scientists stick to their theories despite the fact that they can be falsified or they adopt a new hypothesis even though all the known evidence at the time should have killed them off at birth. This is what we find when we look at the detail of the eventual transition from the Aristotelian to the Copernican view of the world as Feyerabend and Kuhn describe it. It certainly was not the simple falsification of the one by the other. Science works, to some extent, because scientists are dogmatic and not open to falsification. If that is the case, how is it possible to differentiate, or demarcate, science from any other dogma? Will we not have to use different criteria, which are more pragmatic and historical than methodological?

Works Cited

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

Ladyman, J., 2002. Understanding Philosophy of Science, London; New York: Routledge.

Popper, K.R., 2002. Unended quest, London; New York: Routledge.


[1] When we look at science as a method this is a problem. We might ask, however, if we think of science as an activity, whether it is such a problem since science is not a straightforward process of induction.

[2] The source of this story can be found in Popper’s autobiography (Popper 2002, pp.30–8).

[3] Does this open Popper to a more pragmatic account of science than an epistemological one? For if testability is inter-subjective how are we to describe it? Popper appears to want to separate questions of method from question of practice, but later criticisms will in turn want to question this distinction by asking whether it is really the case, when we look at the history of science, that scientists really are committed to the principle of falsifiability. This will be part of Kuhn’s critique of Popper.

Advertisements

The Problem of Induction HM5501 Lecture 3

October 15, 2017

HumeThe justification of science appears at first glance to be the generalisation of experience. I heat metal x and see that it expands, I heat metal y and see that it expands, I heat metal z and see that it expands, and so on, such that it seems natural that I can claim that all metals expand when I heat them. When you hear then talk, then you would think that most scientists think this is what a scientific argument is, and most would also think this is what we might mean by scientific objectivity. There are, however, two questions we might ask of them. First of all, does the inductive method really produce knowledge in the way they think it does, and secondly even if it did is this how science itself operates in its own history? I actually think the second question is more important than the first. The first question is about scientific method, the second is more about what scientists actually do, and not what they say they do. It is a matter of pragmatics, rather than the logical definition of a method in the abstract.

Let us take the first question first, because it is the more traditional problem of induction, and has its canonical form in the argument of Hume. To understand his problem with induction we first of all need to understand, even if in the most basic way, his epistemology. For Hume, there are two kinds of propositions: relations of ideas, and matters of facts. In the first relation, the truth of our ideas is confined by our ideas alone. Thus if you understand the concept ‘bachelor’ you know the idea ‘unmarried man’ is contained within it. When it comes to matters of fact, however, we have to go beyond our concepts to experience. They tell us something new about the world and not just the ideas we already know. A matter of fact would be that Paris is the capital of France, or metals expand when heated. Of course when you know the idea then you know what is contained in it, but to obtain the idea you first of all have to get the knowledge. You only know that Paris is in France, if you have knowledge of basic geography. You only know that metals expand when heated, if you know metallurgy.

There can be false relations of ideas as there can be false matters of fact. Thus if you think that a whale is a fish, then you have made an error about a relation of ideas (you don’t know that a whale is a mammal), and if you think that Plato died in 399 BC, then you have made an error at the level of facts (Ladyman 2002, p.32). Relations of ideas can be proved true by deduction since the negation is a contraction. Basically relations of ideas are tautologies, you cannot assert that Peter is not a bachelor at the same time as asserting that he isn’t married as well, since being unmarried and being a bachelor are one the same thing. On the other hand, matters of fact cannot be proved by logic alone, but can only be derived from experience and their contradiction is not a fallacy. If I say that Everest is the tallest mountain on Earth, none of the terms have a logical relation to one another, so I could assume that there is taller mountain. I would have to experience the different tall mountains on Earth to know which one was tallest or not (Ladyman 2002, p.33). For this reason Hume was extremely sceptical about what one could claim to know deductively. All that one could claim are logical relations between concepts that we already known (whose origin anyway would be the senses). What we cannot claim is to produce new knowledge about the world simply through examining our concepts (as theology and metaphysics is wont to do in his opinion).[1]

These distinctions seem very straight forward and at first glance appear to back up the ‘inductivist’ view of science. The problem for Hume, however, is whether the idea that matters of fact could have the same necessary conclusions as relations of ideas, as the idea of expanding metals as a universal law implies. The key to this problem for Hume is whether I can assert that what happens in the past is a necessary certainty for what will happen in the future. I have experienced the fact that the sun rises every morning. Does this give me the right to say it will rise again tomorrow, when I haven’t actually experience this dawn yet? If it does rise then I will be certain, and in terms of the past, I know that it did rise, but now can I know that I will rise again tomorrow? It is perfectly possible, even if it were unexpected, that the sun might not rise.

Induction for Hume is based upon causal arguments. Our only knowledge of cause and effect is through experience itself because there is no logical reason why any causal relation should hold or not hold. I know matches cause fires, because I know that from experience, not because matches logically contain fire. Just as we can only infer future behaviour of the world from the actual experience of the world, then we can only understand the category of causality from experience. In other words without experience we would not have the concept of causality as a generality. If I always experience the dawn as the rising of the sun then I conjoin this events. If A always follows B, then I will say that A causes B. This because I believe that the future always follows the same path as the past. So that if A happens, then B will happen. Linked to conjunction is contiguity and precedence. Contiguity means that B follows A in time and space, and precedence is that the effect is always after the cause. (the flame is after the lighted match and not before). It is because of conjunction, contiguity, and precedence, that we feel that we have good reason to say that A causes B, or that the sun will rise tomorrow. Hume assertion, however, is that this can never be a necessary reason, as is suggested by generalisation of a universal law, however compelling I feel this causality to be.

Take the example of billiard balls, which seems the most basic relation of causality. The ball X hits the ball Y and causes it to move. But what do we mean by that? Do we mean that the ball X makes the ball Y move or that it produces its movement? We think there is a necessary connection between the two events. X moving and Y moving. What we experience is conjunction, contiguity and precedence, what we do not experience is some mysterious ‘necessary connection’. What we see is ball X and ball Y, what we do not see is some other third thing (like an invisible connection, indeed what we do not see is causality). What does it add to our explanation of the events, even if we were to add this mysterious cause. Wouldn’t the ball X and the ball Y just move in exactly the same way?

The point for Hume is just because two events have always in the past be conjoined, does not mean that we can be universally certain that they will always do so. The conclusion of inductive argument could be false but that would never make it invalid (indeed it might make it more interesting, if the sun did not rise the next day), but this is never the case with a deductive argument if the premises are true, then the conclusion is necessarily true. What underpins the inductive generalisation is the belief that nature is well ordered spatially and temporally, that what happens many times will happen again in the same way. But that is just an assumption. Why must the future always be the same as the past and it certainly is not a logical contradiction if it were not.

Now of course we make these kind of inferences all the time, and Hume accepts that. I probably would not be able to live if I really though the sun would not rise tomorrow every time I went to bed. But this uniformity is a result of our psychology (perhaps it is an evolutionary trait) rather than reason or logic. We find regularity in nature because our habitual associations of events, and not because these events are necessarily connected.[2]

There is no doubt that Hume’s problem is very profound and does make us look at induction more critically, but we might think that the idea that science itself is inductive in the simple way that ‘inductivism’ implies is too simplistic. So the problem is not with induction as such, but how we are using it. It is important to note that this is a very different critique from the methodological one. In the first case, we investigate the method of induction, and like Hume say that is flawed, or might even argue that Hume’s own account of induction is not a correct description of induction.[3] Whereas in the historical account of science, we are arguing whether the description of method is actually how scientists themselves work. One is a description of the content of scientific knowledge, the other is a description of the activity of scientists themselves. Do scientists really act the way that Hume’s example suggests they do? This is a completely different way of doing philosophy of science. For it does not first of all describe a method of doing science and then apply it to scientists, rather it examines what scientists do and from that derives the method. We shall see that this way of understanding science is going to be very important to Kuhn.

Why might we think that scientists do not use the inductive method in the way that induction has been described so far? Take the example of Newton’s Principia (Ladyman 2002, pp.55–6). Newton presents in this work the three laws of motion and the law of gravity. From these laws in explains natural phenomena like planetary motion. He says that he has inferred these laws through induction from observation. Now it is French philosopher of science Duhem that points out that there is a problem with Newton’s explanation. The data he is using is Kepler’s. His data proves that the planet will move in circles, whereas Newton’s in ellipses. This means that he could not have inferred gravity from Kepler’s data, rather he already the hypothesis of the law of gravity to interpret Kepler’s data. Even Kepler’s theory could not have be derived from observation, because he took his data from Brahe, but could only organise it by already assuming that planets moved in circles, a hypothesis he didn’t receive from data, but from the mystical Pythagorean tradition.

So there are two reasons why we might be sceptical of the simple inductive explanation of science. One is methodological through the problem of induction (though we might come up with a better inductive method to solve this), and the other is historical, that science does not work in the way that theory of induction describes. I think the latter is the more serious issue than the former. For in the end science is what scientists do, and not what philosophers might idealise that they do. If you like, the problem of induction is a problem for philosophers. It isn’t one for scientists. They work in a very different way indeed.

Works Cited

Ladyman, J., 2002. Understanding Philosophy of Science, London; New York: Routledge.

 


[1] A group of philosophers from the 20th century called logical positivists also liked this distinction, and differentiated mathematical and logical truths, on the one hand, and science on the other. Anything that didn’t fit this schema was said to be nonsense or meaningless. I am not sure that Hume would have gone that far.

[2] Kant’s argument against Hume is that causality is not merely a habit of the mind but a necessary part of our representation of the world. It would not make sense without it.

[3] This is what Ladyman does when he lists all the different ways in which we might counter Hume, the most telling being induction as the ‘best explanation’ (Ladyman 2002, pp.46–7).


Induction HM5501 Lecture 2

October 2, 2017

BaconLast week we spoke about the difference between science and religion. We said it could be conceptualised as one between belief and facts. The more, we investigated, however, what a fact is, the less certain we became of its status as a starting point for scientific investigation. Common sense might tell us that facts are just out there and we simply observe them and scientific theories are merely collections of these observations, but when we look at the history of science, however, this is not how science works. What we take as facts are already determined by the way we understand and see the world, and our observations are equally shaped by this background conceptuality. In the next two lectures, we are going to investigate the problem of induction, which is probably the classic form of the philosophy of science, and we shall see that we’ll come up against the same barrier again. Moreover, the knowledge that science has of the world cannot itself be infallible, because of the very way that it interprets these facts. In this lecture, however, we’ll give a positive account of induction through Francis Bacon’s method in Novum Organum (1620) and we will investigate the problems of induction in the next lecture.[1]

Ordinarily we might think that scientific theories are obtained from facts through observation and this is what makes it different from belief. But what does it exactly mean that theories are obtained or derived from facts? How do we get from the one to the other? What we mean here is something logical rather than temporal. We don’t just mean that first there is a collection of facts, and then a theory, as though facts were just pebbles on a beach that we pick up. A theory, on the contrary, is supposed to tell us something about these facts before we have even discovered them. It is about meaning and context, rather than just what comes first or second in a temporal order.

What then do we mean by derivation when we speak about logic? We don’t have to go into the complexities of logic here but just the basic form since all we are interested is how theories originate from facts. Logic is based upon deduction. Here is a valid deductive argument, which comes from Ladyman:

All human beings are mortal

Socrates is a human being

Socrates is mortal. (Ladyman, 2002, p. 19)

1 and 2 are the premises and 3 is the conclusion. You cannot deny the conclusion if you take the premises as true. We can change the premises slightly, however, as Ladyman writes, and the deduction would be wrong.

All human beings are animals

Bess is an animal

Therefore Bess is a human being (Ladyman 2002, p.19)

What is important here is that it’s the form of the argument itself that is wrong. The conclusion does not follow from the premises even if one accepts them. Bess could be any kind of animal. What is positive about deductive arguments is that they are truth preserving. That is, if the premises are true and the argument is valid, then the conclusion is. The problem is that the conclusion does not contain any more information than the premises. It does not tell you anything more about the world and surely this is what science does. Although science uses logic and mathematics, it does tell us something new about the phenomena we observe. If it did not, then there wouldn’t be different theories about the world.

From this is follows that if science is derived from facts then it cannot be done so logically, because logic cannot tell us whether a fact is true or not. If we know there are true facts then we can logically relate them together (logic is ‘truth preserving’), but it is only from experience whether we know they are true or not. Take for example the scientific law that metal expands when it heats. It does not matter how many times that I repeat this, as Chalmers argues, it does not logically follow (as is implied below) that all metals will expand when heated:

metal x expanded when it was heated

metal y expanded when it was heated

metal z expanded when it was heated

All metals expand when heated (Chalmers, 1999, p. 44)

If scientific theories don’t come from facts logically, then how are they derived? The answer must be through experience itself inductively. What do we mean by induction? First of all, the difference between deductive and inductive arguments is that in the latter the conclusion always goes beyond what is contained in the premises, as the example above shows. I can never be certain that all metals will expand when heated, because this is precisely what I assert when I move from singular instances (this metal expands when heated) to the universal judgement that all do so.

How then can I adjudicate between a bad and good inductive argument in the way that I did with deductive ones? It would seem, through common sense, that I might be able to justify my universal judgements if I go through many singular observations. In other words, I observe many samples of metal to investigate whether they do expand or not, and if I observe in this large number that they do, then I would be justified in asserting ‘All metals expand when heated’. Thus, the laws of induction would be

1) The number of observations should be large

2) They must be repeated under a wide range of conditions

3) There should be no exceptions.

It is precisely for this reason that English philosopher and scientist Francis Bacon can up with his ‘new method’.[2] First this method is negative. The point is that we should avoid falling into bad arguments rather than coming up with new deductive ones. Bacon’s method is rules about how to practice science by avoiding some of the worst errors. These errors he called ‘idols of the mind’: that we tend to see order and regularity in nature when there is none is the idol of the tribe; that our judgements and are shaped by our language and concepts rather than what we see is the idol of the marketplace; and finally that are views of nature can be distorted by our philosophical and metaphysical systems of thought is the idol of the theatre.[3] From this follows the positive content of Bacon’s method that we ought to make observations of nature that are free of these idols. It is from the mass of information gained through observation that we should make generalisations, rather than understanding our observations through generalisations, which he accuses the philosophers of doing. This he calls the ‘natural and experimental history’.

It is important to understand what Bacon meant by observation is not just looking at the world, but doing experiments, and it this emphasis on experiments that distinguishes the new method from the old Aristotelian one.[4] It is experiments that preserve the objectivity of observations. First, it allows them to be quantified and secondly that they can be repeated by others and thus tested as to their reliability. It is this data from experiments that are then put into tables. To use then example from Bacon of heat: first we have the table of Essence and Presence that lists those things that are directly part of the phenomena of heat; secondly, we have the list of Deviation and Absence, which lists those phenomena that are related to the first but have no heat; and then we have the list of Comparison, where features that have a quantity of heat are listed and quantified. The empirical method is one of elimination. Let us say I argue that the colour white is explanation of heat. Then I would check my tables and I would see that not all the phenomena that are hot are white, or that some phenomena that are white are not hot and so on. White, then, could not be part of theory of heat. Through this process of elimination Bacon explained that heat was caused by the ‘extensive motion of parts’, which is not far from the modern kinetic theory of heat.

Bacon believed one can discover the forms that made what we observed possible, even though they were not directly perceivable. These forms where the direct physical cause of what we saw. This was the rejection of final causes, where natural phenomenon where viewed as purposive. The Aristotelian explanation, for example, that stones fall to the ground was because the earthly element sought to fall to the centre of the earth. Teleological explanations such as these are only suitable for human actions (since humans unlike stones do have desires) but not natural phenomena. The ubiquity of physical causes is the major different between new empirical science of the 17th century and the old science of Aristotle’s era that had dominated the explanation of nature for so long.

There are, however, problems with induction. First, what is the status of the non-observed forms that are the physical cause of what we observe. How can we make a leap from what is seen to what is not seen? It is possible to see how heat might be explained by Bacon’s method since in fact we can see the motion, but how would we go about explaining radiation? Also, we see in science that there can be two competing forms that explain the same visible phenomena such as the two theories of light, for example. Bacon does have an answer for the last problem. He says that we ought to set up two competing experiments that would test what we observe and we could see which was the more successful. But this already demonstrates what we might doubt about Bacon’s new method. In this case are not the theories themselves determining the experiments and not what we observe? Bacon says that science is made from two pillars: observation and induction and that we ought to be able to observe nature without prejudice (the prejudices being the idols of the mind). This is perhaps what most people think that science is. We take many instances and then we generalise a law. Yet the problem is how we account for this mysterious leap from the particular to the universal. How many instances make a general law and if there is an exception does this mean that law is no longer a law?

There are, then, two problems with the principle of induction as Bacon describes it. One is that we might doubt that any observation is unprejudiced. This is not just in a negative sense as Bacon describes it, but also positively, that without a theory it is hard to know what one would observe in the first place. If one didn’t have a theory of electricity why would you set up experiments to observe it? Secondly, we might worry about how it is possible to go from many observations to a general law. Just because X has happened many times before, how do we know we know that it will happen again? This problem of induction, as it is called, and was introduced by the Hume, and has for many made naïve induction untenable. We shall investigate this problem in next week’s lecture.

Works Cited

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

Gaukroger, S., 2001. Francis Bacon and the Transformation of Early-Modern Philosophy. Cambridge University Press.

Harrison, P., 2007. Was there a Scientific Revolution? European Review 15, 445–457.

Ladyman, J., 2002. Understanding Philosophy of Science. Routledge, London; New York.


[1] Although Newton had not read Bacon’s work, his scientific method was widely seen as following his account of induction, and through the fame of the former, has become the ‘common sense’ view of science. For a general account of the importance of Bacon for the image of science, see (Gaukroger, 2001).

[2] See (Ladyman, 2002, pp. 22–5) for this summary of Bacon’s method.

[3] As we can see, what Bacon sees as idols, we might see as unavoidable necessities and this precisely prevents us from accepting the naive inductive explanation of science.

[4] On the importance of experiments to Bacon’s conception of science, and the subsequent transformation of science from a solitary to a communal affair, see (Harrison, 2007).