00:00:19.040 Welcome to Topcast and this is episode 87 if you're an audio only listener. Otherwise it's the
00:00:25.280 discussion of chapter 3 of the fabric of reality. Chapter 3 being titled Problem Solving.
00:00:32.640 This is a great overview of the process of science in particular according to the
00:00:38.400 Papurian worldview and it's a great refutation of all the common misconceptions about how science is
00:00:46.240 supposed to work. Most of those misconceptions are still prevalent today and they come in all
00:00:51.920 sorts of guises I've mentioned this before. For example, Bayesianism is just a new
00:00:57.440 incantation of the problem of induction as applied to science. So what David seems to do here
00:01:04.800 in this chapter is to compile and kind of refine. Poppers take down of induction and it's a really
00:01:12.560 withering takedown here in this chapter of the fabric of reality. But it goes further than just a
00:01:17.920 withering takedown of induction. It gives you the alternative. It gives you the correct idea about
00:01:23.600 how science actually manages to generate objective knowledge about the world. And I would say that
00:01:30.960 no one who actually understands what this chapter is saying can remain a Bayesian or can remain
00:01:36.560 confused about what induction is supposed to be and what the problem of induction is let alone
00:01:42.880 how science really proceeds and really generates knowledge. And they would tend not to use phrases
00:01:48.720 like this evidence confirms the theory or this makes me more confident that the theory is true
00:01:54.480 and so on if you properly understand what's being said in this chapter. And this chapter is of
00:01:59.440 course timely and timeless. Right now we are in an epoch where politicians in particular are
00:02:08.000 supposed to follow Verscience, Capital T, Verscience. In other words there is supposed to be a
00:02:14.880 scientific consensus and all of us should have policies based on Verscience as if the
00:02:20.720 science is settled and we often talk about Versatile Science. But this is wrong and this is wrong
00:02:25.680 because science like every other area of knowledge is conjectural and at any time it can be overturned
00:02:33.360 by new evidence, new theories that explain what previously seemed to be true but in fact turn
00:02:41.120 out to be strictly speaking faults. Of course none of this is to say we shouldn't take our best
00:02:47.280 explanations seriously as our best explanations of the world and thereby make policy informed by
00:02:54.640 those best explanations. But whether or not the best explanations we have are really good
00:03:00.720 explanations. Well that's another matter. Sometimes the best explanation might be something like
00:03:05.280 we don't actually really know what's going on here. We don't have a good explanation. That could
00:03:09.680 be the best explanation, ironically, whatever the case. If you want to level up your thinking,
00:03:14.960 I think this chapter is a great place to start. It's a chapter that if you are so far not familiar
00:03:22.000 with the work of David Deutsch and Karl Popper, it's going to challenge your intuitions
00:03:27.600 and reformulate I would say the way in which you do think. That happens with all of David's chapters
00:03:33.680 in both of these books of course but this one in particular really will take the legs out from
00:03:38.480 underneath you if you haven't considered carefully these particular issues before. So whether you
00:03:44.800 have thought deeply about how science works or if you haven't, if you're unfamiliar with critical
00:03:51.120 rationalism or Popper's worldview, this chapter might very well blow your mind. So the chapter is
00:03:56.560 called problem solving and Popper actually had a book called All Life is Problem Solving and he
00:04:04.080 really meant it. If you can continue to solve your problems then you will just keep on going on
00:04:09.520 living solving your problems and in fact the joy is found in perpetually solving your problems.
00:04:14.800 The only reason you die is because you haven't been able to solve that problem but it too is
00:04:18.720 soluble and in fact if we consider life more broadly as in the evolution of species over time
00:04:25.280 that too on Popper's view was an attempt at problem solving what the genes are trying to do is to
00:04:31.440 solve the problem of how to survive in a certain niche. Now whether or not you want to push the
00:04:35.920 analogy that far I don't know but all of us have problem situations things that we're interested
00:04:41.520 in at a particular time and place and we're trying to sort out in order to have more fun,
00:04:47.040 be more healthy, have a more flourishing life and so on and so forth. So although any particular
00:04:52.240 problem might be parochial and might just be about you at a particular time and place.
00:04:56.640 This concept of life of problem solving is a universal one it's the way in which knowledge is
00:05:03.840 generated it's a certain lens through which we can view the way in which progress actually
00:05:10.320 happens. Progress happens by continually identifying and then solving problems or in other words
00:05:16.800 detecting errors and then correcting them. So all of this is a similar way of orbiting a
00:05:22.480 conception of what knowledge is all about. Now this chapter contains a lot of very deep ideas,
00:05:29.520 a lot of subtle ideas and a lot of what you might call aphorisms that I'm going to highlight
00:05:34.480 as we go through. It's dense, it's counterintuitive for people who again are not familiar with
00:05:40.640 this critical rationalist view of the way in which knowledge is generated. So it might
00:05:46.640 take a while to get through this chapter as compared to some of the others but we will persevere
00:05:51.280 and we'll get there in the end and hopefully we'll be able to clarify what papyrus said
00:05:57.040 and what David has said and what my understanding of this chapter is as always. Without further ado
00:06:03.840 let's get into it. Chapter three, problem solving and David writes, I do not know which is stranger.
00:06:10.880 The behavior of shadows itself or the fact that contemplating a few patterns of light and
00:06:15.360 shadows can force us to revise so radically a conception of the structure of reality. The argument I
00:06:22.400 have outlined in the previous chapter is not withstanding its controversial conclusion,
00:06:27.200 a typical piece of scientific reasoning. It is worth reflecting on the character of this reasoning
00:06:32.480 which is itself a natural phenomenon at least a surprising and full of ramifications as the
00:06:38.800 physics of shadows pausing their my reflections. So just remember that in the previous chapter
00:06:44.080 called shadows, it was essentially about the shadows being cast by, well at first a torch and
00:06:50.560 then a laser light. When the light passes through a double slit, this famous double slit experiment,
00:06:57.520 first done by Thomas Young back in the 1800s. And if you fire this single photon of light,
00:07:03.280 this single particle of light at the apparatus, you end up getting an unexpected interference
00:07:08.800 pattern. And through the chain of explanation that David provides in that previous chapter, go to the
00:07:14.320 previous episode of the fabric of reality for that. What you conclude, what you are forced into
00:07:20.560 concluding, the only known explanation of this is that there must be other photons that you cannot
00:07:26.080 detect in this universe. In other words, the universe is tremendously larger than what we think.
00:07:31.360 This is why we call it a multiverse because there are these other universes which are approximately
00:07:38.640 parallel to our own. They don't interact very often except through these interference experiments.
00:07:43.280 So this, what would otherwise might be turned an insignificant observation of the movement of
00:07:49.760 single photons leads to this tremendous conclusion that we live in a multiverse. Now,
00:07:55.920 a lot of people argue against this through simple incredulity. It's like, how could it be so? How could
00:08:01.040 this small amount of evidence lead to such a stupendous conclusion? But we can refer to any number
00:08:07.680 of other observations like this. David makes this point elsewhere that the history of astronomy
00:08:13.120 certainly is a history of seeing smudges on a photographic plate here rather than there. And that leads
00:08:20.400 to the conclusion that there is a whole galaxy of stars out there. Or imagine trying to explain to
00:08:26.640 the ancients that in rocks, we would find evidence that rules in favor or rules out. All other
00:08:34.160 theories except that there used to be these large flightless bird type creatures roaming the earth
00:08:41.520 millions upon millions of years ago. And that's found in rocks. Well, that some of the pinpricks of
00:08:47.280 light that the ancients could see in space were actually whole other worlds just like our own.
00:08:52.240 And in fact, beyond that, there were pinpricks of light that could not be seen except by the use
00:08:57.600 of melted sand which arranged in a metal tube would reveal these distant objects. All of the
00:09:05.280 knowledge that we have today seems from a particular perspective, the perspective of an ancient,
00:09:11.360 to be bizarre and ridiculous. A bizarre and ridiculous conclusion to draw on such
00:09:16.560 scant evidence. And the multiverse conclusion is just another in that long lineage of strange
00:09:24.480 stories that we tell about the world which just happened to be true. Let's continue and David
00:09:29.760 writes. To those who would prefer reality to have a more prosaic structure, it may seem
00:09:35.760 somehow out of proportion unfair even that such momentous consequences can flow from the fact
00:09:42.080 they tiny spot of light on the screen should be here rather than there. Yet they do. And this is
00:09:47.600 by no means the first time in the history of science that such a thing has happened. In this
00:09:51.840 respect, the discovery of other universes is quite reminiscent of the discovery of other planets
00:09:56.800 by early astronomers. Before we sent probes to the moon and planets, all our information about
00:10:02.880 planets came from spots of light or other radiation being observed in one place rather than another.
00:10:09.920 Consider how the original defining fact about planets the fact they are not stars was discovered.
00:10:15.120 Watching the night sky for a few hours, one sees that the stars appear to revolve about a particular
00:10:20.640 point in the sky. They revolve rigidly, holding fixed positions relative to one another.
00:10:26.400 The traditional explanation was that the night sky was a huge celestial sphere,
00:10:30.720 revolving around the earth and that the stars were either holes in the sphere or glowing embedded
00:10:35.600 crystals. However, among the thousand points of light in the sky visible to the naked eye,
00:10:41.280 there are a handful of the brightest which over longer periods do not move as if they were fixed
00:10:47.120 on a celestial sphere. They wonder about the sky in more complex motions. They are called
00:10:51.520 planets from the Greek word meaning wanderer. Their wandering was a sign that the
00:10:56.880 celestial sphere explanation was inadequate. Successive explanations of the motion of planets
00:11:02.880 have played an important role in the history of science. Capernicus's heliocentric theory placed
00:11:08.960 the planets in the earth in circular orbits around the sun. Kepler discovered that those orbits
00:11:14.480 are ellipses, rather than circles. Newton explained the ellipses through his inverse square
00:11:20.080 law of gravitational forces and his theory was later used to predict that the mutual gravitational
00:11:25.600 attraction of planets would cause small deviations from elliptical orbits. The observation of
00:11:32.000 such deviations led to the discovery in 1846 of a new planet, Neptune, one of many discoveries
00:11:38.080 that spectacularly corroborated Newton's theory, pausing their just my reflection. This word corroborate
00:11:45.280 yet proper uses it. It kind of means in this sense consistent with, but if you go and look
00:11:50.960 it up in a dictionary, what you find is that it says something like confirm or support,
00:11:55.760 which is absolutely not what is meant here. If your theory makes a prediction, for example,
00:12:01.680 if you use Newton's theory of gravity, to predict that the reason why Uranus Uranus is being perturbed,
00:12:08.960 it's orbit is being perturbed, is because there's another planet out there called Neptune,
00:12:13.200 and if you go looking and you find Neptune, that does not confirm, that does not support,
00:12:18.480 that does not say that Newton's theory is actually correct or true, or something like that,
00:12:24.800 probably true, anything like that. What it means is that there is no other theory that can do
00:12:30.160 as good a job as Newton, and so Newton's theory contains some truth within it, and any theory that
00:12:36.640 could not make such a prediction is therefore ruled out as inferior to what Newton's is.
00:12:42.480 All of this might be summed up with the word corroborate. It's just that warning,
00:12:46.240 flagging the situation that if you go to the dictionary and you look up what corroborate means,
00:12:51.120 sometimes you'll see confirm or support, explicitly not what Popper and Deutsch
00:12:56.240 mean by the word. Let's continue, David writes. Nevertheless, a few decades later,
00:13:02.560 Einstein's general theory of relativity gave us a fundamentally different explanation of gravity
00:13:07.040 in terms of curved space and time, and thereby predicted slightly different motions again.
00:13:12.880 For instance, it correctly predicted that every year the planet Mercury would drift by about
00:13:17.440 one-ten-thousandth of a degree, away from where Newton's theory said it should be,
00:13:23.200 it also implied that starlight passing close to the sun would be deflected. Twice as much
00:13:29.520 by gravity as Newton's theory would predict. The observation of this deflection by Arthur
00:13:35.200 Edington in 1919 is often deemed to mark the moments at which the Newtonian worldview ceased
00:13:41.120 to be rationally tenable. Ironically, modernary appraisals of the accuracy of Edington's
00:13:46.560 experiments suggest this may have been premature. The experiment, which has since been repeated,
00:13:51.200 with great accuracy, involved measuring the positions of spots, the images of stars
00:13:55.920 close to the limit of the sun during an eclipse on a photographic plate. As astronomical predictions
00:14:01.120 became more accurate, the differences between what successive theories predicted about the appearance
00:14:07.280 of the night sky diminished. Evermore powerful telescopes and measuring instruments
00:14:12.400 have had to be constructed to detect the differences. However, the explanations underlying these
00:14:18.320 predictions have not been converging. On the contrary, as I have just outlined, there has been a
00:14:24.400 succession of revolutionary changes. Thus, observations of ever smaller physical effects have been
00:14:31.840 forcing ever greater changes in our worldview. It may therefore seem that we are inferring ever
00:14:37.920 grander conclusions from ever scantier evidence. What justifies these inferences, pausing their
00:14:44.960 my reflection. The first thing here is that there has been a debate even among people who identify
00:14:50.880 as perperians about the extent to which and whether or not we are converging on anything like reality
00:14:57.360 or the truth or something like that. Given that it seems as though one new theory of gravity
00:15:04.640 or one cosmological theory seems to utterly overturn the previous theory. And so this sometimes
00:15:11.840 leads some perperians to gravitate towards what might be called a kunian worldview, Thomas Kuhn,
00:15:17.600 a far more popular philosopher, sociologist of science, a great rival of Papa. He's the most
00:15:25.840 again, I think I've mentioned this before. He wrote the structure of scientific revolutions,
00:15:31.520 the most cited work in the social sciences ever. Because it basically says that
00:15:36.960 science goes through these revolutions, much like happens in the social sciences. And so it
00:15:42.480 cuts the physical sciences down to size and it says, well, it's not really taken in a certain sense.
00:15:48.560 Some people think that it means that scientific knowledge is not objective. It just goes through
00:15:52.880 trends or fashions, that kind of thing. The fancy word used is paradigm. So we have a Newtonian
00:16:00.320 paradigm and then we have an iron-stinian paradigm and these two paradigms have nothing to do with
00:16:05.920 one another and one person operating in one paradigm can't see the truth of the other paradigm.
00:16:10.960 They both work within a certain domain and we can't say that we're converging on anything
00:16:16.640 like reality or the truth. The problem with this whole idea is that it concentrates on what
00:16:23.760 changes from theory to theory and not what remains the same from theory to theory. The simple
00:16:29.680 fact is that whether you are working with Kepler or Newton or Einstein, planets still exist.
00:16:37.440 This thing called gravity still exists. We just don't know the nature of it. What happens
00:16:42.560 is that in Kepler, there's some reason why called gravity that the planets go around the sun.
00:16:50.160 When we get to Newton, we say it's a force but it doesn't know what causes the force.
00:16:54.320 We still have planets and we still have orbits. And when we get to Einstein, we still have
00:16:58.400 planets. We still have orbits. We still have this thing called gravity and we still say that it's
00:17:02.960 approximately the that are approximately a Bayes the inverse square law and this is why we have
00:17:08.240 approximital ellipses in terms of all that's but we get to explain what the true nature of gravity
00:17:13.520 is so far as we know now, the curvature of spacetime. So so much is being preserved. It's not all
00:17:19.200 overthrown. It is an a complete revolution. Many of us like to concentrate on the fact that what
00:17:24.400 we're having is an incremental change in various parts of the theory. Of course, some parts are
00:17:30.640 utterly overturned but not the entire content of our understanding of that particular concept,
00:17:36.720 let alone all of our knowledge. I don't like to agree with the people who say it's a complete
00:17:42.240 revolution. It's not a complete revolution. A complete revolution actually undoes everything.
00:17:47.600 Everything that was good is completely cast aside and we're implementing something else for
00:17:52.720 reasons of fashion for not a good reason. And this happens in politics and if you would
00:17:57.520 take it seriously in science, what you would be saying is we're going to throw away even the
00:18:02.240 existence of planets, even the existence of orbits as we change from one theory of gravity to another.
00:18:07.920 But we're not. We're not doing that at all. We're throwing away some things,
00:18:11.840 replacing with others, tweaking things, coming to a deeper understanding but we're preserving
00:18:17.280 a whole bunch as well. So that's one thing. The other thing is David says, what justifies these
00:18:24.400 inferences. Now, I would encourage everyone to get a hold of the audiobook of the fabric of reality.
00:18:31.200 It's relatively new and at the beginning of that audiobook is an introduction by David Deutsch himself
00:18:37.840 and in that introduction recorded what 20 years after he first wrote the book, he says that he would
00:18:44.400 put certain things differently and one of the key things that he would put differently is use of
00:18:49.920 the word justifies and it comes up again in chapter seven of the fabric of reality where he says,
00:18:55.520 it really needs to be interpreted as an indication of the morally right thing to do or the
00:19:02.960 methodologically right thing to do. That's what he means by justifies. Unfortunately, it can have
00:19:08.880 echoes of justification. It doesn't mean that when you say what justifies such and such,
00:19:14.080 that you are saying what demonstrates as true such and such. That's not what he means.
00:19:20.240 Now, I tend to think that when I read the fabric of reality and I read David's use of the word
00:19:26.080 justifies. I'm reminded and I hope that David doesn't regard this as an insult. I'm reminded
00:19:30.480 what Wittgenstein said of his own philosophy. After all Wittgenstein, if you recall some of my other
00:19:36.880 podcasts I've talked about this, Wittgenstein argued that there are no such thing as philosophical
00:19:41.040 problems and going further that therefore there's no good reason for philosophy. All of our knowledge
00:19:47.040 can come to us via science and perhaps mathematics. But you have no need really for philosophy and so
00:19:53.200 then of course people might object to Wittgenstein himself and say, well hold on Wittgenstein,
00:19:56.720 you are a philosopher and you have a philosophy. Are you saying of your own philosophy that it's
00:20:01.520 useless? And he said, kind of, it's like a ladder in order to get yourself out of a deep well
00:20:07.840 if you've fallen in. That's a well-being philosophy. What you do is you use Wittgenstein's philosophy
00:20:13.760 to climb your way out of the well and then once you're out of the well you can also cast aside
00:20:19.680 the ladder. You don't even need that anymore either. Clever, clever little quip but I like to
00:20:24.160 actually think that that's the way to understand David's use of the word justify because if you
00:20:29.120 really do understand what's being said in the fabric of reality, you realize there is no way
00:20:34.320 in which you can actually justify as true anything at all. You can't justify stuff in science
00:20:40.400 or anywhere else. And by the end of the book you understand that. So that's what the word
00:20:45.840 justifies. It's like David gives you the ladder in order to throw away this justificationist scheme
00:20:51.920 and so you can even throw away the word to a large extent as well. However in order to get there
00:20:56.400 you have to grant people who don't yet agree with you the word justify. Okay so it
00:21:02.720 takes a while to undo these things. It's like the word confirm or support and various other things.
00:21:07.920 If I'm speaking with someone that he the two is completely unfamiliar with the popper
00:21:13.040 and that whole way of speaking, I might very well use the word confirm and support and that kind of
00:21:17.840 thing until such time as I can help them to understand the popularian worldview and once they do
00:21:24.720 then you can turn around and say you never you needed to use the word support and you can
00:21:28.480 never actually confirm a theory so you can do away with those entire concepts but until such time
00:21:34.000 as you're both speaking the same philosophical language you're going to have to meet them halfway
00:21:38.960 and so that's the way in which I interpret justify in this book. So anyway David goes on to say
00:21:46.400 quote can we be sure that just because I star appeared millimetrically displaced on
00:21:51.440 Eddington's photographic plate space and time must be curved or that because I photo
00:21:56.480 detector at a certain position does not register a hit in weak light there must be parallel
00:22:01.200 universes. Indeed what I have just said under states both the fragility and the indirectness
00:22:08.240 of all experimental evidence for we did not directly perceive stars spots on photographic plates
00:22:14.800 or other external objects or events we see things only when images of them appear on our
00:22:21.600 retinas and we do not perceive those images until they have given rise to electrical impulses
00:22:27.280 in our nerves and those impulses have been received and interpreted by our brains
00:22:32.400 thus the physical evidence that directly swathes us and causes us to adopt one theory
00:22:38.080 a worldview rather than another is less than millimetering it is measured in
00:22:43.280 thousands of emilometer the separation of nerve fibers in the optic nerve and in
00:22:48.240 hundreds of adult the changes in electric potential in our brains in our nerves that make the
00:22:54.720 difference between our perceiving one thing and perceiving another pausing there just my reflection
00:22:59.840 on this if you hear the phrase evidence is theory laden or something like that this is one sense
00:23:07.920 in which that phrase is cashed out when you hear that phrase evidence is theory laden or perception
00:23:13.840 is theory laden any of those things this is what is meant by that that when you say you've seen
00:23:21.280 something it's not a direct experience because we know we have a theory of site and how it works
00:23:29.280 and it's complicated it's not simply that you look outside and you see the sun shining what that
00:23:36.960 means is photons of light have actually entered your eyes and those photons of light have fallen
00:23:43.040 upon your retina which have given rise to well actually it's really complicated it goes through
00:23:48.320 causes chemical changes in the photosensitive cells of the eye in the light sensitive cells of the eye
00:23:54.960 and that gives rise to electrical impulses which travel along the optic nerve and then to the
00:23:59.360 brain so this whole process is what seeing is it is a complicated process speaking of perceptions
00:24:06.560 now your perception might change a little bit because I've decided that I'm going to just
00:24:11.440 slightly alter my setup here so that the audio sounds a bit better when I record video the
00:24:18.560 audio sounds one way I've noticed and when I don't by plugging my microphone directly into my
00:24:24.880 computer it sounds better you don't need to hear all the details I suppose anyway you won't be
00:24:29.440 seeing my face again for the remainder of this episode this is just an experiment I want to see here
00:24:34.960 the difference between the audio only type version and the video on audio type version
00:24:43.040 an overall majority of people only listen to me they don't watch me it's like a ratio of 10
00:24:48.240 to 1 almost and so just to make things a little bit easier from the I'm just going to record
00:24:53.840 audio only for the remainder of this with the exception that there are a few images to come
00:24:59.760 and the reason they're images to come is because David provides them in the book and I so I
00:25:02.960 want to show you those images so they'll be important but for now I'm just switching to audio only
00:25:08.960 okay so here we are back with the audio only version now to my ear this sounds better and it's also
00:25:17.840 rather easier for me to edit however if I get feedback to say that people would prefer the video
00:25:24.560 then I will continue to do that and I'm not going to stop doing that at least for the introductions I
00:25:30.080 would say but for rather the majority of the podcast makes things a lot easier and I think it
00:25:36.640 actually sounds better if I'm just doing audio for various technical reasons anyway let's keep
00:25:44.080 going I'm up to the point in the book where David writes quote however we do not accord
00:25:50.960 equal significance to all our sensory impressions in scientific experiments we go to great lengths
00:25:56.560 to bring to our perceptions those aspects of external reality that we think might help us to
00:26:01.600 distinguish between rival theories we are considering before we even make an observation we
00:26:07.440 decide carefully where and when we should look and what we should look for pausing their
00:26:12.720 my reflection okay this idea that we look for observations which can decide between rival theories
00:26:20.240 is so important this is the concept of a crucial test and David has written an absolutely
00:26:27.040 wonderful paper all about this called the logic of experimental tests with a particular emphasis
00:26:33.760 on ever reading in quantum theory but you can actually read through the paper without
00:26:37.200 a bothering with the quantum theory part unless you're a quantum physicist because it explains
00:26:42.080 what the point of a crucial test is this particular jewel in the crown if you like of
00:26:48.880 the scientific method insofar as there is a scientific method but this point of crucial test is
00:26:55.440 where you've got two rival theories there is an observation which will rule out one of them leaving
00:27:00.800 you with only one theory that explains the evidence before you this is where certain subjects
00:27:07.680 let's just call them out let's say psychology sometimes gets things wrong if you're going around
00:27:13.680 collecting data and you're trying to extrapolate from the data but you don't actually have a
00:27:19.200 theory to begin with you're missing the point of science you're missing the point of collecting data
00:27:24.000 collecting data essentially amounts to doing an experiment actually going out into the world
00:27:28.880 making observations but in psychology rather too often they simply collect data and then don't
00:27:36.000 have an explanation before they begin collecting the data here's a caricature or a cartoonish version
00:27:41.840 of such a psychological study and the other reason I know about this is because in schools of
00:27:47.360 certain kinds you can actually study a subject called psychology now what they do there is they
00:27:53.520 actually can force the students to undertake an experimental study and what they do is they do things
00:28:00.160 like well let's check how impulsive different groups of people are so let's check how impulsive
00:28:07.280 people are given their gender so we'll check how impulsive a male person is versus a female person
00:28:14.720 and the way in which you might do this well the standard thing of let's put them in a room with
00:28:19.440 a cake for a little while and let's see who eats the cake first and let's say you have a
00:28:24.080 statistically significant number of occasions where it's the male that takes a bite out of the cake
00:28:30.400 before the female does and so on this basis you then draw the conclusion therefore males are
00:28:35.440 more impulsive than females but you haven't actually at any point figured out the reason why
00:28:42.480 all you're saying is that there is a correlation that you've discovered there's no explanation
00:28:46.880 there though is it really the maleness versus the femaleness is that the thing is it something
00:28:52.240 deeper than that is it something about the amount of testosterone and if it is the amount of
00:28:56.400 testosterone why by what mechanism or is it something deeper still than that is it in the
00:29:01.520 genes if it is in the genes how so is it something to do with the weighing which males are raised
00:29:08.160 as children that causes to be more impulsive which could rule out this whole idea that males are
00:29:13.360 more impulsive than females in the first place it could simply be a cultural thing have nothing to
00:29:18.880 do with males whatsoever and having everything to do with ideas this is the poverty of explanation
00:29:26.400 less science you can't do an experiment a legitimate experiment a useful experiment until such times
00:29:33.760 you have an explanation and the explanation is then going to be tested again to reality that's
00:29:39.920 what the experiment is and in fact it's even worse than this because if you have only one
00:29:45.360 explanation and you do do an experiment and the experiment disagrees with your explanation there is
00:29:51.280 no way to refute throw away discard the explanation after all how then you go about explaining the
00:29:57.600 observations you are making and how do you know that it's not the experimental method that is
00:30:02.960 falling apart that is the reason for the disagreement this is the Jewham coin thesis again and
00:30:07.600 pop was fully aware of it and George is fully aware of it and anyone who is a proper
00:30:11.120 barbarian is fully aware that sometimes you can do an experiment and although the experiment disagrees
00:30:17.840 with the explanation with the scientific theory that doesn't necessarily it doesn't logically
00:30:22.320 mean that the theory is wrong especially in a case where you only have one explanation the only
00:30:29.440 explanation the scientific explanation which is why David has said there quote and I'll just continue
00:30:34.640 reading before we even make an observation we decide carefully where and when we should look
00:30:41.440 and what we should look for often we use complex specially constructed instruments such as
00:30:47.600 telescopes and photo multipliers yet however sophisticated the instruments we use and however
00:30:52.880 substantially external causes to which we attribute their readings we perceive those readings
00:30:58.240 exclusively through our own sense organs there is no getting away from the fact that we human
00:31:03.760 beings are small creatures with only a few inaccurate incomplete channels through which we receive
00:31:10.240 all information from outside ourselves we interpret this information as evidence of a large
00:31:16.480 and complex external universe or multiverse but when we are weighing up this evidence
00:31:21.840 we are literally contemplating nothing more than patterns of weak electric current trickling
00:31:27.280 through our own brains pausing their my reflection now you will notice if you are a
00:31:32.000 dutch super fan so to speak that he has used the phrase there weighing up this evidence
00:31:38.960 and again that might set off alarm bells I'm sure he doesn't literally mean in fact we know
00:31:44.240 he doesn't literally mean weighing up this evidence because he explains this in the beginning of
00:31:48.800 infinity what would be meant there is just a prosaic idea of considering this evidence okay we're
00:31:54.800 not weighing some evidence against others it's just a turn of phrase we're not actually weighing up
00:32:01.120 by some process after all evidence doesn't have a particular weight either the evidence agrees
00:32:07.360 with an explanation or it doesn't and if it doesn't then we have a problem and we have to guard
00:32:13.360 out solving that problem if we have two theories and it agrees with one explanation but does not
00:32:19.840 agree with the other the one that it doesn't agree with is refuted typically speaking could always
00:32:25.520 be it can always logically be the case that the experiment has been performed incorrectly it always
00:32:31.520 comes down to explanations and argument and having a good understanding of what's going on
00:32:36.240 throughout the experiment but especially in cases where you only have one theory and you have
00:32:43.040 one experiment which disagrees with your one theory you simply have a problem you don't know what's
00:32:48.080 going wrong you're not in a position to say therefore the theory is incorrect you don't know
00:32:54.240 you don't know if the theory the explanation is incorrect or your theory of the experiment is
00:32:59.520 incorrect the theory of how the instrument that is being used in the experiment is working that
00:33:05.440 it's all theories everything observation is theory laden as we say perception is theory laden
00:33:10.800 the evidence is theory laden the whole world is theory laden it's all being interpreted by your
00:33:16.480 mind and back to the book what justifies the inferences we grow from these patterns it is certainly
00:33:23.280 not a matter of logical deduction there is no way of proving from these or from any other
00:33:29.440 observations that the external universe or multiverse exists at all let alone that the electric
00:33:35.360 currents received by our brains stand in any particular relationship to it anything or everything
00:33:42.080 that we perceive might be an illusion or a dream illusions and dreams are after all common
00:33:48.720 solipsism the theory that only one mind exists and that what appears to be external reality
00:33:55.120 is only a dream taking place in that mind cannot be logically disproved reality might consist of
00:34:02.080 one person presumably you dreaming a lifetime's experiences or it might consist of just you and me
00:34:08.960 or just the planet earth and its inhabitants and if we dreamed evidence any evidence of the
00:34:14.160 existence of other people or other planets or other universes that would prove nothing about how
00:34:20.080 many of those things they're really are pausing there just my reflection so this idea of
00:34:26.240 solipsism this idea that only you exist and everything's being dreamed into reality it just keeps
00:34:31.680 cropping up again and again in the history of philosophy one of the earliest mentions is of course
00:34:37.040 Plato's cave this idea that what he got right of course in in Plato's cave is that we only
00:34:43.360 have access to our senses we don't have direct access to reality but taken too far it means that
00:34:50.080 perhaps external reality doesn't even exist at all that all you have are just your senses they
00:34:56.560 can't came up with a method of doubt and he thought that well it could be possible that there
00:35:01.120 would be this evil demon that might be deceiving you you know this all powerful almost all powerful
00:35:06.320 demon that could be tricking you into thinking the external reality actually exists some sort of
00:35:12.320 creature with superpowers then the movies the matrix are all about this as well that perhaps we're
00:35:18.640 sitting inside of some sort of computer simulation type thing and taken to an even more extreme
00:35:24.560 we have Nick Bosch from simulation hypothesis all of these are logically equivalent they're what
00:35:29.600 literally tannett has called super naturalism this idea that you're just appealing to some idea
00:35:35.760 that is a priori beyond our capacity to refute well refute experimentally anyway because it puts
00:35:42.880 itself beyond what physics can possibly probe in other words beyond physical or natural or it's
00:35:48.640 supernatural super naturalism I think that's exactly right we can ignore all these things because
00:35:55.520 we can refute them not by experiment but by argument which is where David's going to get to
00:36:01.040 and so David picks up the discussion where he writes quote since solipsism and an infinity of
00:36:08.080 related theories are logically consistent with your perceiving any possible observational evidence
00:36:14.800 it follows that you can logically deduce nothing about reality from observational evidence how
00:36:20.640 then could I say that the observed behavior of shadows rules out the theory that there is only
00:36:27.040 one universe or that eclipse observations make the Newtonian worldview rationally untenable how
00:36:34.080 can that be so if ruling out does not mean disproving what does it mean why should we feel
00:36:40.320 compelled to change our worldview or indeed any opinion at all on account of something being
00:36:46.720 ruled out in that sense this critique seems to cast out on the whole of science on any reasoning
00:36:52.880 about external reality that appeals to observational evidence if scientific reasoning does not
00:36:58.160 amount to sequences of logical deductions from the evidence what does it amount to why should we
00:37:04.640 accept its conclusions this is known as the problem of induction pausing them our reflection
00:37:12.320 okay so let's just recap that here so that we have in mind a clear understanding of what we
00:37:19.280 mean by the problem of induction so the story goes typically if you ask someone who is familiar
00:37:28.080 let's say with science but not necessarily with the philosophy of science what we do in science
00:37:35.760 to produce knowledge of the physical world what they might say sometimes is we make observations
00:37:43.120 and from those observations we deduce explanations we read from the book of nature so to speak
00:37:51.600 we observe the world and then from those observations logically derive a theory about what's going
00:37:59.840 on and in fact by the way this is what the Bayesians kind of think they just think that they
00:38:05.520 derive probably true theories rather than absolutely true theories and they can calculate
00:38:12.560 how confident they are in the theory that they deduce from these observations but whatever the
00:38:18.720 case this problem of induction as it was classically framed was something like well you observe day
00:38:27.280 after day morning after morning the sun rising and therefore you deduce in some way the theory
00:38:35.680 that the sun will continue to rise tomorrow now of course that's merely a prediction that's
00:38:39.920 our next one what we're about to get to that as well as David goes on to say quote the name
00:38:45.440 problem of induction derives from what was for most of the history of science the prevailing theory
00:38:51.360 of how science works the theory was that there exists short of mathematical proof
00:38:57.600 a lesser but still worthy form of justification called induction pausing there just my
00:39:03.680 reflection again this word induction has lots of different meanings firstly there is a deductive
00:39:10.320 method in mathematics called proof by induction and it is deductive so it's important not to
00:39:18.160 get the two confused because they're actually opposites of one another one is a logical method
00:39:24.240 of proof in mathematics what typically happens by the way and this is this happens in high school
00:39:29.280 mathematics among other things what you do is you're given a formula you then show that the formula
00:39:35.200 works for n equals one it's valid for n equals one then you assume that it's true for some general
00:39:41.440 case n equals k and then you show that given that assumption it actually works for n equals k plus
00:39:47.360 one and given that you've already shown that it works for the n equals one case then substituting
00:39:53.680 n equals one for n equals k and showing that therefore it works for one then two and off into infinity
00:39:59.840 given the formula you've just got you've proved via the method of induction that this formula works
00:40:06.000 for all possible cases of n now that's perfectly valid that is a perfectly valid way of doing
00:40:12.720 mathematical proof it's deduction by unhappy coincidence I get I haven't looked into the history
00:40:19.360 of this but by unhappy coincidence I guess that the philosophers of science early on went well there
00:40:24.560 must be a similar method in science we're going to use the same word induction where we can prove
00:40:29.600 such a thing holds for all cases often to infinity this doesn't work for a whole bunch of reasons
00:40:34.640 because unlike with a mathematical formula which is necessarily true it's predictable in
00:40:41.920 necessarily true ways the physical world is not like that it's not like that at all we know this
00:40:47.360 we know that tomorrow doesn't look like yesterday things change in the physical world all the time
00:40:52.720 we don't understand all the reasons why by the way but the certainly the laws of physics
00:40:57.360 mandate that not everything that happens from day to day today will be precisely the same
00:41:03.360 there are other forms of induction as well by the way this word induction it also works in
00:41:07.760 physics in various ways this is well it has different meanings there's charging something by
00:41:13.760 induction so if you have an electric charge on one object and you bring it close to another object
00:41:18.560 which is either to not yet charged and then in bringing these two things closer what happens
00:41:23.520 the neutral one well let's say let's say you've got an object a the way that electrical
00:41:27.920 induction works well static electrical induction anyway imagine two spheres metal one of which
00:41:34.720 has a negative electric charge you've charged the bias some methods and a second sphere which is
00:41:40.880 neutral you bring them close to each other but not touching not touching and if you have them
00:41:45.520 such they're not touching in the both metal spheres the first of which is negative well it will
00:41:49.360 push away the negative charges on the second sphere and you can then discharge those negative
00:41:54.960 charges on the second sphere because you have this dipole and when you do do the discharging this
00:41:59.600 is called charging by induction now there's also other kinds of electrical induction as well
00:42:05.840 that go on there's also the induction that happens when an employee enters a new workplace of
00:42:12.160 the first time they undergo a process of induction so induction is curious in that it has very very
00:42:19.280 many different meanings that have very little to do one with another but this kind of induction
00:42:25.760 this induction in the philosophy of science it's about if you can't derive logically
00:42:33.440 if you can't prove that a particular theory is true given the evidence perhaps you can get
00:42:39.040 almost true a highly confident something like that and so we don't have deduction but we have
00:42:44.240 induction which is almost as good that's what was hoped for in science David writes
00:42:50.480 induction was contrasted on the one hand with the supposedly perfect justification provided
00:42:56.480 by deduction and on the other hand with supposedly weaker philosophical or intuitive forms of
00:43:02.080 reasoning that do not even have observational evidence to back them up in the inductive
00:43:07.040 theory of scientific knowledge observations play two roles first in the discovery of scientific
00:43:13.280 theories and second in their justification a theory is supposed to be discovered by extrapolating
00:43:20.400 or generalizing the results of observations then if large numbers of observations conform to the
00:43:26.640 theory and non deviates from it the theory is supposed to be justified made more believable
00:43:32.240 probable or reliable this scheme is illustrated in this picture that I'm putting up on the screen
00:43:37.760 or figure 3.1 in the original book just pausing their my reflection on this I've written an
00:43:44.080 article that's on my website and you can just google my name Brett Hall induction and it should
00:43:49.360 come up for you and it's an attempt to show that precisely that sentence there the David writes
00:43:54.720 where he said quote if large numbers of observations conform to the theory and non deviates from it
00:44:01.120 the theory is supposed to be justified made more believable probable or reliable and my favorite
00:44:05.840 example of this is anyone with a thermometer and a stove and a pot of water can do the experiment
00:44:14.880 where you turn on the stove which typically is a relatively constant source of heat and monitor the
00:44:20.480 temperature over time and if you plot a graph of the temperature versus the time and you have no clue
00:44:26.320 or you pretend to have no clue about what's going to happen next you will notice a wonderfully
00:44:32.480 linear trend or very close to linear anyway for example maybe every minute the temperature of the
00:44:39.200 water goes up by 10 degrees Celsius and if you monitor the temperature between you know 20 degrees
00:44:45.360 Celsius up to 80 degrees Celsius you get this lovely trend line and you could you could monitor
00:44:49.120 at every single degree that it rises what does this suggest well let's suggest that if you
00:44:53.760 think induction is a thing then you can extrapolate the theory that as you heat the water it
00:45:00.480 continues to rise in temperature now until until you boil the water you don't know that at 100
00:45:06.880 degrees Celsius something special and unexpected happens the temperature of the water doesn't
00:45:12.800 continue to rise but you only know that you would only know that observation if you actually
00:45:17.600 ever got to the point where you reach the boiling point of water you can never rule out there's
00:45:22.880 not going to be a surprising observation out there like the boiling of water so anyway I think
00:45:28.480 that that is proof enough so to speak refutation enough at least that induction cannot possibly be
00:45:36.160 the way that science works putting aside what David's about to say next that it's not even
00:45:42.720 predominantly about extrapolation and prediction that's just a small part and anyway you can't make
00:45:48.400 the prediction until you have an explanatory theory behind you let's keep going David writes quote
00:45:55.360 the inductivist analysis of my discussion of shadows would therefore go something like this
00:46:00.160 we make a series of observations of shadows and see interference phenomena stage one the results
00:46:06.160 conform to what would be expected if there existed parallel universes which affect one another in
00:46:10.320 certain ways but at first no one notices this eventually stage two someone forms the generalization
00:46:17.120 that interference will always be observed under the given circumstances and thereby induces the
00:46:23.120 theory that parallel universes are responsible with every further observation of interference
00:46:28.880 stage three we become a little more convinced of that theory after a sufficiently long
00:46:34.320 sequence of such observations and provided that none of them ever contradicts a theory we
00:46:39.120 conclude stage four that the theory is true although we can ever be absolutely sure we are for all
00:46:44.960 practical purposes convinced it is hard to know where to begin criticizing the inductivist
00:46:50.400 conception of science it is so profoundly false in so many different ways perhaps the worst
00:46:55.920 flaw from my point of view is the sheer non sequitur that a generalized prediction is tantamount
00:47:01.920 to a new theory pausing there going back and just reading that that's really important
00:47:07.680 the sheer non sequitur that a generalized prediction is tantamount to a new theory okay so what
00:47:17.840 David saying there is that just making a prediction so if you're observing again classic theory classic
00:47:26.400 example rather the sun rising each day and on that basis you say therefore the sun will rise
00:47:32.000 tomorrow that's not a new explanatory theory you've been explained anything you're just saying
00:47:36.640 what will happen tomorrow but you've never said why you haven't said why that whole thing
00:47:42.480 that the blacks one thing you know you're just observing whites one after whites one after white
00:47:47.360 swan and therefore you conclude on that basis that all swans are white but that's not a theory
00:47:52.720 either that's not really a part of science saying all swans are white we want to know why why are
00:47:58.000 swans white why can't there for example be black swans even though there are that's not what
00:48:04.320 these science of ornithology the study of birds is about it's about trying to have an
00:48:09.280 understanding of the commonalities between different birds species what a bird is as distinct from a
00:48:14.800 mammal and so on and so forth it's not all swans are white it's not all xy or the sun will
00:48:22.480 continue to do this tomorrow or those things are derivations from good explanations which we don't
00:48:30.400 yet have on this conception of how science works but we're about to get there in the
00:48:34.800 purian view so David goes on to say like all scientific theories of any depth the theory that
00:48:41.120 there are parallel universes simply does not have the form of a generalization from the observations
00:48:49.600 did we observe first one universe then a second and a third and then induce that there are
00:48:54.480 trillions of them was the generalization that planets will wander around the sky in one pattern
00:48:59.840 rather than another equivalent to the theory that planets are worlds in orbit around the sun
00:49:05.120 and that the earth is one of them it is also not true that repeating our observations is the way
00:49:10.640 in which we become convinced of scientific theories as I have said theories are explanations not
00:49:16.560 merely predictions if one does not accept a proposed explanation of a set of observations making
00:49:22.000 the observations over and over again is seldom the remedy still less can it help us to create a
00:49:28.720 satisfactory explanation when we cannot think of one at all pausing their my reflection
00:49:34.160 it's interesting in the history of astronomy as well if you look at people trying to explain
00:49:39.680 astronomers trying to explain early on how the solar system formed the theory of our solar system
00:49:46.640 actually reached out beyond the solar system two other stars so the story here is that
00:49:54.160 around our sun coalesced all the other planets which formed from that original gas and dust cloud
00:50:00.480 out of which the sun formed as well and so did the other stars out there what do I bring this up
00:50:05.040 well we hadn't yet observed any other planets out there orbiting any other stars until I think
00:50:12.080 94 1994 I think that was the first time we saw if it wasn't then it was very close to then
00:50:17.120 certainly we hadn't actually seen with our telescopes any evidence of planets orbiting other stars
00:50:23.440 prior to let's say 1980 but theories of solar system formation were absolutely there
00:50:29.040 and suggested there should be planets orbiting most stars out there that was already thought
00:50:35.760 as being the case but the theory that we had of those planets also said that with the current
00:50:42.320 telescope technology we couldn't observe them they had to invent new techniques in order to observe
00:50:47.600 the planets that they predicted and thought were there so it wasn't like we were
00:50:52.560 observing planet after planet after planet orbiting star after star after star in order to reach
00:50:57.280 the conclusion that therefore there are planets orbiting most stars no we already had the theory
00:51:02.480 about solar system formation which applied not only to our solar system but also to all other
00:51:08.400 stars out there that's how science works we have the conjectured creative explanation which
00:51:14.960 reaches out from the thing we're observing to all the unobserved stuff and then maybe later
00:51:20.240 we can figure out ways to observe that unobserved stuff or hitherto unobserved stuff as we did with
00:51:26.400 extra solar planets David goes on to say as I have said theories or explanations not merely
00:51:32.160 predictions if one does not accept a proposed explanation of a set of observations making the
00:51:37.440 observations over and again is seldom the remedy still less can it help to create a satisfactory
00:51:42.800 explanation when we cannot think of one at all you're not just to repeat what David said there
00:51:48.640 as I have said theories are explanations not merely predictions if one does not accept
00:51:54.800 a proposed explanation of a set of observations making the observations over and over again
00:52:00.560 is seldom the remedy still less can it help us to create a satisfactory explanation when we cannot
00:52:07.440 think of one at all furthermore even mere predictions can never be justified by observational
00:52:14.560 evidence as Bertrand Russell illustrator in his story of the chicken okay pausing here I'm
00:52:19.680 just going to tell this in my own words just to make it faster than merely reading it so this
00:52:25.440 idea of Russell's chicken was I've had the parable of Russell's chicken which I think I'll tell
00:52:29.760 that a dozen times now in this podcast series the idea is this farmer is keeping a chicken
00:52:35.920 and the chicken is being fed day after day after day and so the chicken who's an inductivist
00:52:40.800 reasoner of a kind thinks that he's going to continue to be fed day after day after day
00:52:48.160 well he's sorely disappointed when on Christmas Eve or something like that his neck is
00:52:54.400 wrung and he's killed and biked and eaten by the farmer now what does this say well it says that
00:53:02.960 you number one you already need a theory in mind don't you you need to have the theory
00:53:07.920 that the farmer has some sort of benevolent feelings towards you if you're the chicken
00:53:13.840 being fed day after day after day but there's another theory that is consistent with those
00:53:17.600 observations perfectly consistent which is that the farmer is fattening you up to slaughter you
00:53:24.720 for Christmas dinner and an infinite number of other explanations as well as to why you're
00:53:31.120 being fed day after day after day the thing is whether or not you have a good explanation
00:53:35.840 and can be experimentally tested in some way what David says all about this in his way is that
00:53:42.000 um this disappointment experienced by Russell's chicken has also been experienced by trillions
00:53:47.120 of other chickens this inductively justifies the conclusion that induction cannot justify any
00:53:54.400 conclusions however this line of criticism lets inductivism off far too lightly it does illustrate
00:54:02.320 the fact that repeated observations cannot justify theories but in doing so in entirely misses
00:54:09.040 or rather accepts a more basic misconception namely that the inductive extrapolation of observations
00:54:14.800 to form new theories is even possible okay so that again that the inductive extrapolation of
00:54:22.560 observations to form new theories is even possible in fact it is impossible to extrapolate observations
00:54:32.000 unless one already has placed them within an explanatory framework for example in order to
00:54:37.920 induce its false prediction Russell's chicken must first have had in mind a false explanation
00:54:43.200 of the farmer's behavior perhaps it guessed that the farmer harbored benevolent feeling
00:54:46.960 towards chicken causing their more reflection yes so the idea is you need you start with theories
00:54:53.120 you must have a theory to begin with before you can make an extrapolation so in this case the theory
00:54:58.320 was it's almost like you're assuming the conclusion you're assuming okay the farmer is benevolent
00:55:05.280 okay that's the idea so therefore the farmer will continue to feed the chicken
00:55:10.080 well why is the farmer continuing to feed the chicken because of benevolent it's this wonderfully
00:55:13.440 self-contained little thing but whatever the case you've already got the theory there the theory
00:55:18.960 is already in hand it's not observations leading to the theory no it's a theory that explains
00:55:25.200 the observations or purportedly explains the observations in fact it's quite wrong it's a false
00:55:30.320 explanation absent absent a theory you're not really saying much like if I go back to that the
00:55:36.160 son has risen every day of my life let's say and I say well on that basis therefore the son will
00:55:42.960 rise again tomorrow what problem am I solving it is the problem should I expect the son to rise
00:55:49.600 tomorrow and if if the answer is yes why because it's risen every day previously how does that
00:55:57.680 follow it follows only if I have an explanation as to why all times in the past should resemble
00:56:05.680 all times in the future you know for example in the real in the real case you know this particular
00:56:10.160 place on the earth the earth is rotating and therefore that causes the son to come to appear on the
00:56:15.760 horizon approximately every 24 hours but of course we now it's completely false if you go you know
00:56:20.880 up to the arctic circle or something like that I'm skipping apart and David goes on to explain
00:56:25.760 more about Russell's chicken you know the on the one hand you can say Russell's chicken extrapolates
00:56:31.120 and he's going to continue to be fed every single day based on the fact that he has thus far been
00:56:35.680 fed every single day and on the other hand if he has a different theory that he's being fed
00:56:40.640 every single day only because he's being fattened up so they can be slaughtered well you've got the
00:56:46.560 same set of observations you know namely on being fed every single day leading to two contradictory
00:56:54.160 theories so what does David say about that he goes on to write quote the fact that the same
00:56:58.800 observational evidence can be extrapolated to give two diametrically opposed predictions according
00:57:04.640 to which explanation one adopts and cannot justify either of them is not some accidental limitation
00:57:11.840 of the figure out environment it is true of all observational evidence under all circumstances
00:57:17.040 observations could not possibly play either of the roles assigned to them in the inductive
00:57:22.480 scheme even in respect of mere predictions that alone genuine explanatory theories admittedly
00:57:29.120 inductivism is based on the common sense theory of the growth of knowledge that we learn from
00:57:33.360 experience and historically it was associated with deliberation of science from dogma and tyranny
00:57:39.040 but if we want to understand the true nature of knowledge and it's placed in the fabric of reality
00:57:43.360 we must face up to the fact that inductivism is false root and branch no scientific reasoning
00:57:49.120 and indeed no successful reasoning of any kind has ever fitted the inductivist description
00:57:55.040 pausing their my reflection yes so of course we have this idea which is also known as empiricism that
00:58:03.120 it at least gets something right okay there's something that it gets right is better to learn from
00:58:08.640 experience better to learn from an encounter with reality how is that better better than what
00:58:14.960 better than authority better than just opening up your scripture let's say or listening to the
00:58:21.840 man wearing the dress the priest or whatever listening to what they say and just doing what they say
00:58:27.200 okay which is certainly better than just making you all up on your own constantly as well okay so
00:58:31.840 there are there are degrees of getting things wrong so to speak trying never to learn anything
00:58:38.720 and never listen to anything never to observe anything that's one level of error thinking that
00:58:43.840 one particular person or one particular book has all the answers that's another level
00:58:47.680 at least you're taking into account the ancient wisdom perhaps and then there is of course well
00:58:54.480 let's actually get feedback from reality in some way shape or form but if you think that getting
00:58:58.960 feedback from reality in the form of just repeatedly observing the same thing over and over again
00:59:03.760 is the why that it works that's wrong as well so all of those ways aren't as good at all they
00:59:10.960 don't capture the truth anywhere near like the critical rationalist way the popularian view of
00:59:18.320 observations are about ruling between competing theories okay which is what we're about to get to
00:59:24.640 David goes on to write quote what then is the pattern of scientific reasoning and discovery
00:59:32.480 we have seen that inductivism and all other prediction centered theories of knowledge are based
00:59:38.000 on a misconception what we need is an explanation centered theory of knowledge a theory of how
00:59:44.160 explanations come into being and how they are justified a theory of how why and when we should allow
00:59:51.840 our perceptions to change our worldview once we have such a theory we need no separate
00:59:57.680 theory of predictions for given an explanation of some observable phenomenon it is no mystery how
1:00:04.320 one obtains predictions and if one has justified an explanation then any predictions to
1:00:10.000 write from that explanation are automatically justified to pausing the more reflection now remember
1:00:14.240 of course David Deutsch is the person that figured out what a good explanation is and therefore a
1:00:21.840 way of distinguishing between different explanations this hard to vary criterion which meant that
1:00:28.880 well you know people make discovery throughout their life and so between the time of writing this
1:00:35.120 the fabric of reality and the beginning infinity apparently he's created the good way of delineating
1:00:42.240 between good and bad explanations which makes this talk of justification redundant like I say you could
1:00:49.280 view it as being Wittgenstein's latter allowing you to climb out of the well of justificationism
1:00:55.280 and once you're out of that well you can just discard the latter and you don't need to use the word
1:00:58.960 anymore but better yet read this in light of the beginning infinity just consider that the beginning of
1:01:05.600 infinity the content there explains what really a good explanation is so we don't have to worry
1:01:10.880 about justifying explanations we just have to worry about what a good explanation is compared to
1:01:15.360 a bad explanation or non explanation and therefore if we have competing good explanations at a
1:01:19.760 particular point in time what means by which we will refute one not the other and in science of
1:01:25.920 course that's the crucial experiment anyway here David goes on to write fortunately the prevailing
1:01:31.200 theory of scientific knowledge which in its modern form is too largely to the philosopher
1:01:36.480 Karl Popper and which is one of my four main strands of explanation of the fabric of reality
1:01:41.600 can indeed be regarded as a theory of explanations in this sense it regards science as a problem
1:01:48.080 solving process inductivism regards the catalog of our past observations as a sort of
1:01:54.080 skeletal theory supposing that science is all about filling in the gaps in that theory by
1:01:58.960 interpolation and extrapolation problem solving does begin with an inadequate theory but not
1:02:04.640 with the notion of theory consisting of past observations it begins with our best existing theories
1:02:10.880 when some of those theories seem inadequate to us and we want new ones that is what constitutes
1:02:16.640 a problem thus contrary to the inductive a scheme shown in figure 3.1 scientific discovery
1:02:23.760 need not begin with observation evidence but it does always begin with a problem by a problem
1:02:30.080 I do not necessarily mean our practical emergency or a source of anxiety I just mean a set of
1:02:34.160 ideas that seems inadequate and worth trying to improve the existing explanation may seem too
1:02:39.840 glib or too labored it may seem unnecessarily narrow or unrealistically ambitious one might glimpse
1:02:45.200 a possible unification with other ideas or a satisfactory explanation in one field may appear
1:02:51.280 to be irreconcilable with an equally satisfactory explanation in another or it may be that there have
1:02:58.320 been some surprising observations such as the wandering of planets which existing theories
1:03:03.840 did not predict and cannot explain this last type of problem resembles stage one of the inductive
1:03:11.040 a scheme but only superficially for an unexpected observation never initiates a scientific discovery
1:03:19.440 unless the pre-existing theories already contain the seeds of the problem for example clouds wonder
1:03:26.720 even more than planets do this unpredictable wandering was presumably familiar long before planets
1:03:32.800 were discovered moreover predicting the weather would always have been favorable to farmers
1:03:38.400 seafarers and soldiers so there would always have been an incentive to theorize about how clouds
1:03:43.920 move yet it was not meteorology that blazed the trail for modern science but astronomy
1:03:50.320 observational evidence about meteorology was far more readily available than in astronomy
1:03:55.040 but no one paid much attention to it and no one induced any theories from it about cold
1:04:00.640 fronts or anticyclones the history of science was not crowded with disputes dogmas heresies
1:04:06.400 speculations and elaborate theories about the nature of clouds in their motion why because under
1:04:12.560 the established explanatory structure for weather it was perfectly comprehensible that cloud
1:04:17.760 motion should be unpredictable common sense suggests the clouds move with the wind when they drift
1:04:24.160 in other directions it is reasonable to surmise that the wind can be different at different altitudes
1:04:30.080 and is rather unpredictable and so it is easy to conclude that there is no more to be explained
1:04:35.040 some people no doubt took this view about planets and assumed that they were just glowing objects
1:04:40.320 on the celestial sphere blown about by high altitude winds or perhaps moved by angels and that
1:04:46.480 there was no more to be explained but others were not satisfied with that and guessed that there
1:04:51.920 were deeper explanations behind the wandering of planets so they searched for such explanations
1:04:58.240 and found them at various times in the history of astronomy there appeared to be a mass of unexplained
1:05:04.560 observational evidence at other times only a sintilla or not at all but always if people had chosen
1:05:11.680 what to theorise about according to the cumulative number of observations of a particular phenomena
1:05:17.200 they would have chosen clouds rather than planets yet they chose planets and for diverse reasons
1:05:23.600 some reasons depended on preconceptions about how cosmology ought to be or on arguments advanced
1:05:30.160 by ancient philosophers or on mystical numerology some were based on the physics of the day others
1:05:36.320 on mathematics or geometry some have turned out to have objective merit others not but every one
1:05:42.480 of them amounted to this it seemed to someone that the existing explanations could and should
1:05:49.280 be improved on one solves a problem by finding new or amended theories containing explanations which
1:05:56.000 did not have the deficiencies but do retain the merits of existing explanations this figure three point
1:06:03.280 two from the book shows that after a problem presents itself which is stage one the next stage
1:06:09.760 always involves conjecture proposing new theories or modifying or reinterpreting old ones and the hope
1:06:16.160 of solving the problem that stage two the conjectures have then criticized which if the criticism
1:06:21.840 is rational entails examining and comparing them to see which offers the best explanations
1:06:27.760 according to the criteria inherent in the problem which is stage three when a conjectured theory
1:06:33.280 fails to survive criticism that is when it appears to offer worse explanations than other
1:06:38.960 theories to it is abandoned if we find ourselves abandoning one of our originally held theories
1:06:44.560 in favor of one of the newly proposed ones which is stage four we tentatively deem our problem
1:06:49.600 solving enterprise to have made progress I say tentatively because subsequent problem solving
1:06:56.640 will probably involve altering or replacing even these new apparently satisfactory theories
1:07:02.160 and sometimes even resurrecting some of the apparently unsatisfactory ones thus the solution
1:07:08.320 however good is not the end of the story it is a starting point for the next problem solving
1:07:14.000 process which is stage five this illustrates another of the misconceptions behind inductivism
1:07:20.400 just pausing their my reflection this is a reminiscent of now I'm going to have to go from
1:07:26.000 memory here um a quotation from pop bar and he said words to the effect anyway I'm going to
1:07:32.800 mangle the exact quotation but something to the effect of I think there is only one way to do
1:07:38.000 science or any kind of inquiry for that matter and that is to fall in love with a problem until
1:07:44.160 such time as you solve it at which point you will find a whole family of new daughter problems
1:07:50.960 in other words if you find a problem you're really interested in and you solve it you will find
1:07:56.960 that in solving that problem it doesn't end your quest there in fact it reveals it gives birth
1:08:03.520 to if you like it gives rise to all these other more interesting problems as well you know this is
1:08:09.280 the history of science for example uh in in solving the problem of what's the correct theory of
1:08:16.320 gravity or the more correct theory of gravity and Newton's theory of gravity or on sincere gravity
1:08:20.640 once we figure out we've solved the problem it's on science theory of gravity we then have a
1:08:25.120 whole bunch of other new problems what can we use this new theory of gravity for what does it
1:08:30.240 permit or what does it prohibit what does it allow all these new kinds of technologies based
1:08:35.520 upon this new theory of gravity so we end up with a whole bunch of new problems that quest
1:08:41.760 for identifying problems and solving those problems thereby growing knowledge is an unending
1:08:47.040 quest and on this point David writes and this is I think where we'll end it for today as he said
1:08:54.400 the solution however good is not the end of the story does starting point he goes on to say
1:09:00.240 this illustrates a number of the misconceptions behind inductivism in science the objective of the
1:09:06.480 exercises not to find a theory that will or is likely to be deemed true forever it is to find
1:09:14.480 the best theory available now and if possible to improve on all available theories a scientific
1:09:21.360 argument is intended to persuade us that a given explanation is the best one available it does not
1:09:28.640 and could not say anything about how that explanation will fair when in the future it is subjected
1:09:34.160 to new types of criticism and compared with explanations that have yet to be invented a good explanation
1:09:40.560 may make good predictions about the future but the one thing that no explanation can even begin to
1:09:46.080 predict is the content or quality of its own future rivals just pausing their end of the reading
1:09:54.640 for today note that really important limitation upon the growth of knowledge that David really
1:10:00.400 emphasizes in the beginning of infinity but here it is here in the fabric of reality that
1:10:06.160 no theory today no explanation we have can predict the content of its successes that would be
1:10:14.720 to predict the growth of knowledge something that cannot be done and this is why by the way we
1:10:21.680 can't predict what people will do at moment to moment people are knowledge creators they're inherently
1:10:27.760 unpredictable they use their capacity to generate knowledge to come up with the subsequent theories
1:10:34.160 but you can't predict the content of those subsequent theories if you did you would have it in
1:10:38.880 hand already so it wouldn't be a prediction it would be a theory that you already have this is why
1:10:45.680 we say it's inherently unpredictable if it was predictable if the growth of knowledge was
1:10:51.840 predictable then suddenly logically you would have a prediction of the future knowledge that is to
1:10:58.080 come but that's not possible if it was possible again it would mean that you've generated that
1:11:03.520 knowledge now and so you'd have it now so it wouldn't be a prediction in the first place it's
1:11:10.240 such a subtle point easily missed I prediction is about a future state of affairs but if you're
1:11:16.880 saying that the content of future knowledge is x, y and z and x, y and z is only supposed to be
1:11:22.880 discovered in the future at some point but you've discovered it now how is that a prediction
1:11:26.960 that's just a statement of the knowledge that you have now not the knowledge that you will have in
1:11:31.280 the future it's the knowledge that you have now so it ceases to be a prediction it's a curious
1:11:35.920 outworking of this particular way of arguing but it is completely sound that's what the truth of
1:11:42.000 the matter is and that is why people are unique and unpredictable and although they're determined
1:11:48.240 by laws of physics like everything else they're inherently unpredictable and this is why we use
1:11:53.680 terms like freewill at least why I use a term like freewill to label this unusual quality that
1:12:01.040 people have that sets them apart from all other known systems in the universe not merely other
1:12:08.080 animals everything else we know of everything else we've hitherto been able to create generate
1:12:13.600 explain okay so once we can explain ourselves how it is we go about generating these explanations
1:12:19.280 still we won't be able to predict the future content of our knowledge but we might have
1:12:24.800 whatever the algorithm is that is able to generate explanatory knowledge and then we'll have the
1:12:31.600 algorithm for a person but even then we won't be able to predict what that person will do that
1:12:36.480 person will have a creative capacity to generate explanations or freewill whatever you want to say
1:12:42.800 anyway going off on my hobby horse again that's why we'll end up for today there's still
1:12:48.320 more yet to read in this chapter problem solving this in all encompassing really vision not only
1:12:55.840 of science but as Popper said all life is problem solving all of the different areas of our
1:13:03.520 intellectual life that we're interested in our personal life that we're interested in
1:13:07.440 and just all the ways in which we might want to make progress personally as a community
1:13:12.800 as a civilization is encapsulated by this problem solving enterprise rather than a search for
1:13:21.440 final truth which would be an end of science and end of knowledge creation we don't expect
1:13:29.120 that we just expect to continually solve problems that's the way to find contentment in the world
1:13:36.160 to continually solve your problems that's fun finding solutions continuously and then finding
1:13:43.920 new problems that are more interesting that's one of the meanings of the life okay until next time bye-bye