Fine tuning - evidence for God or for multiple universes?

0:00 I'll take them back myself. So, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b-block, b- Thank you for your attention. So, yes, when I go on a conference, most of the other conferences, I go to Harvard, and I'm a college teacher, and I go to Harvard, and I go to Harvard, and I go to Harvard, and I go to Harvard, and I go to Harvard, and I go to Harvard, Speakers include mathematics, geometry, algebra, mathematics, physics, quantum mechanics, physics, quantum mechanics, physics, quantum mechanics, physics, quantum mechanics, physics, quantum mechanics, physics, quantum mechanics, physics, quantum mechanics, physics, quantum mechanics, physics, quantum mechanics, physics, quantum mechanics, Where is it? I don't know if you know, but any of these conceptions may be unknown. Thank you for your attention.

2:30 The technological side is that with this sort of revolution, you can only store 18,000 cars in 10,000 cars. But the most efficient one is the T-Series. Yes, you can run up to a mega-business on the T-Series side, and I think the T-Machines are like that. I think the T-Machines are like that. I think the T-Machines are like that. I'm not a member, that's ridiculous. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. I'm not a member. Okay, I think we think we can start. I'm delighted to welcome John Leslie. John Leslie this year is in fact a joint National Academy of Sciences in Canada and British Academy lecturer, so he's giving a number of lectures here. He's a sort of academic ambassador. Well, also from Canada. Royal Society of Canada. No, no, the Royal Society of Canada. No, they're about to change it to the National Academy because the British Royal Family is so unpopular. Ah, right. Royal Academy of Canada. I do, I do. Royal Society of Canada. That's right, Royal Society of Canada. Excuse me. Would it be possible, rather than waiting until afterwards and gambling through the selection choice table notes, would it be possible to have both of these in your responses? Of the transparencies, I've only got one or two transparencies, and I haven't... I can make photographs of them, but it's a bit of a chore, but if you twist my arm, I'll see what I can do.

5:00 I beg your pardon? I know, yes, but I... It can be done, but I really need an assistant, as it were, to slave over a hot photocopier while I do something else. Yes, certainly, yes, indeed. I actually have my photocopier. This is the only complicated transparency I have. But yes, you can do it yourself. John Leslie is a very unusual philosopher, both in his grasp of really quite intricate physics and his attempt, as it were, to make philosophical and indeed also theological sense of things. And he's written a number of very impressive books. The one that is perhaps most relevant to this course is his book, Universes, but he's also an earlier book, Value and Existence. Now in paperback and Dutch he has! He, like Dorothy Sayers, his career after leaving Oxford actually started in advertising and then he went into teaching. I must confess I think that advertising and teaching have a hell of a lot in common. Anyway, we're delighted to have you with us. I won't take up any more of the time in which we want to hear you talking. Okay, well, since you've got a lot of me today, let me explain that these sessions fall into two parts. In the first part, which will occupy the first session, I will be talking about the apparent way in which you might want to revive the design argument for God's existence on the basis of recent cosmological findings. And in the second part, I will be talking about whether the notion that there exists a God makes any sense.

7:30 The design argument for God's existence, otherwise known as the argument from design or the teleological argument, is an argument to the existence of God from the apparent signs of this in the universe. And so, as has often been said, it's an argument to design, really, rather than an argument from design. You look at the universe and you see signs that it seems as if it had been designed, and you then conclude, well, it has been designed, and then you say the only plausible designer is an infinite being, infinitely knowledgeable, powerful, and all the rest. That's the way that people have used the argument from design to get to God. And a lot of people have thought that the argument from design has been completely knocked on the head by Darwin. Because although it's fairly clear that living beings look as if they've been very cunningly designed, Darwin had an explanation for this, which is familiar to all of you, in terms of successive slight improvements in the structure of things, improvements which lead always in the direction of greater success at reproduction. And the notion is that you can get very, very complicated mechanisms looking exactly as if they had been designed, produced by natural selection without any actual designer. However, in order to get Darwinian evolution working, you do need a complicated universe which is fairly stable. And last a large number of years with the complexities not disappearing. And there is a large amount of modern evidence which is suggested to some physicists and some philosophers of religion, some theologians, has suggested that the universe we find ourselves in is... As is put, fine-tuned in such a way as to make Darwinian evolution possible. The idea here is that the laws of nature can be expressed as equations, and into these equations there come particular numbers.

10:00 And the suggestion is that these numbers have to be chosen very, very carefully in order that you can get a universe in which life would be able to evolve, a universe in which the Darwinian process would be able to lead to living beings. For instance, one needs a universe, it's often thought, in which there is such a thing as chemistry. And it suggested that chemistry would not be possible were it not for the fact that the difference between the mass of the neutron and the mass of the proton is just about exactly twice the mass of the electron. This was a point which was mentioned by Stephen Hawking in his inaugural lecture at Cambridge. And he said that were it not for this neutron-proton mass, The difference being so carefully adjusted, you wouldn't have had the couple of hundred stable nucleotides, as you put it, which are the basis of chemistry and then of biology. And the reason effectively is that if you muck around with those masses, you either get just neutrons or you just get protons and you don't get complicated atoms which require both neutrons and protons. Well, this would be one way in which it could seem that the universe had been fine-tuned through God's choosing those particular masses. And there's a large number of other claims about fine-tuning and I have put up some of them here. In my book on this subject I listed about 80 of these claims. Some of them are much more controversial than others. One of the things you keep on coming across is the possibility that certain numbers which you think you can put freely into your equations, you think that God could have put freely into his equations, choosing the numbers arbitrarily, in fact could be somehow dictated by basic theory. So it could be that where we've... Where present-day physicists think that certain numbers could have been chosen arbitrarily by God, actually in order to get a consistent system, God would have had to put particular numbers into particular places in the equations, in the formulae.

12:30 And this means that a lot of this so-called fine-tuning evidence is very controversial. But at the same time there's sufficient number of claims of fine-tuning to have persuaded a lot of people that something rather odd is going on here and when the people are theologically inclined they will tend to say the responsible factor is God and that is the view which has been taken by for example John Polkinghorne who was professor of I was a professor of mathematical physics at Cambridge and then I gave that up in order to become a priest. He takes the view that the so-called fine-tuning evidence is really rather good and the natural way of explaining it is that God did a good job of putting in the right numbers into the physical laws. But there is another approach. To this same evidence, if it is so evidence, if it's good evidence, and the other approach involves saying that there are a vast number of universes and that the numbers which I've been talking of, which are often referred to as constants. Aren't in fact constant across the universes. They are randomized across the universes. There's a vast number of universes and these various numbers which are so important to the possibility of having a world in which Darwinian evolution will get going and be able to produce complicated living beings such as ourselves. That possibility depends on having the numbers right in at least one universe. But there are vastly many of these universes. And if the numbers are randomized across the universes, sooner or later the numbers will all come out right. It's like saying if you had sufficiently many monkeys typing at typewriters for sufficiently long a time, sooner or later you'll get one which types the entire Encyclopedia Britannica. Well, here are the two possible ways of accounting for this so-called evidence of fine-tuning, the way which appeals to God, says that God fine-tunes the various crucial numbers, and the other which says that you have multiple universes, and sooner or later, one at least of the universes will come out with all the right numbers for Darwinian evolution to occur.

15:00 And then the crucial move, which is probably obvious to you, would be that that's the universe which we find ourselves in, or if there's a small group of universes which are all with the numbers coming out by chance just right for evolution of the Darwinian sort to be possible, then we're in one of that small group of universes. We have to be in a universe where life could have evolved because we are in a universe in which life did in fact evolve. Before going any further, I should make clear that when you talk about many universes here, you are not actually involved in a contradiction. I'm talking about many actual universes. And some people would say, particularly if they're trained in philosophy, which is a very tedious subject in many respects, some people will say, it has been proved, it has long been known by philosophers that you cannot have two universes. It's a matter of definition. Two universes is like a married bachelor. The universe is by definition everything that there is, so there can only be one of them. That is a tedious philosophical move which is luckily getting less and less made by philosophers. When I talk about this subject occasionally if I have an audience of philosophers there will be an indignant hand raised and an exasperated sigh and somebody will say, oh you must be simply talking about possible universes because when it comes to actual ones we all know that there is only one. Well, the cosmologists these days don't use the word universe like that. The cosmologists use the word universe to mean a region which is typically very large, but not necessarily. Typically very large, which is more or less independent from other such regions. It hasn't got much causal interaction with the other regions, so it may interact with them at its edges. It may be completely separate. It may have its own separate space of time. And a typical reason for talking of regions as different universes would be that you thought that their characteristics were very different. So the more that regions of reality as a whole are looked on as separate from each other causally, the more they are looked on as...

17:30 These are very large. It helps if they're very large regions. This helps them to be called universes, and the more that their characteristics are thought of as varying, the more you will be inclined to talk of these regions as separate universes. This has led to a lot of verbal confusion in the area, because what one person would like to call a universe, some other person would simply like to call a very large region. And you can see how this sort of thing works. If you look at a typical modern cosmological theory, which was introduced to us yesterday, the theory that we have a cosmos which has inflated, the theory here is that at very early moments of the Big Bang, there was a sudden accelerated expansion. Instead of the Big Bang constantly slowing down thanks to the influence of gravity, there was a very brief period of very fast expansion at which everything was blown up to tremendous size in a very, very small fraction of a second. And the result of this theory is to say that the region which we're actually able to see, the region... Which our telescopes can in theory probe, which is about radius 10 billion light years, that's just a very rough figure, that region is only an enormously small part of the total universe. Even in its first moments the universe could have inflated by a factor of perhaps 10 to the power of a million. That's a factor of one followed by a million zeros. It could have got that many times larger than it had been during a very short period. And effectively that would mean that now the region which we can see stands to the size of the whole thing in something like the proportion of one to... One followed by a million zeros. Something like that sort of proportion. You can get this quite easily out of some versions of the inflationary theory. In fact, you can get even much more inflation than that. On this view, we just see a very, very small part of reality. And there will be a tendency to talk about the parts beyond our horizon, beyond what we can see, as are the universes.

20:00 If you believe that the total cosmos is divided into domains in which the forces of nature have broken apart in different ways, the characteristics of the domains would then be such that, for example, some of them wouldn't have any such discipline as chemistry applicable to them because the mass of the neutron and the mass of the proton had come out wrong. This sort of theory is very speculative, but it has been given a certain amount of scientific bite, because people have worked out ways in which the various parts of a large universe could have the characteristics of the particles and so on in them made different, made subject to chance, and one way of looking at this matter is to say, well, it's... All due to the fact that at very early moments in the Big Bang, all particles didn't have mass, or technically speaking they didn't have rest mass. They're like the photon today, which doesn't have any rest mass. The photon particle of light has no rest mass. And it's often thought that all particles were like this very early in the Big Bang. And then later a field appeared, which is called a scalar field. Or maybe there are several such scalar fields and the result of the appearance of these scalar fields or this scalar field was that particles became massive to different degrees. They became massive through interacting with the field. And the suggestion is that this field could have taken different values in different regions of the universe. Just by chance because it was so to speak equally easy for it to take the various different values. It's as if a ball was rolling off a hilltop and it would be equally easy for the ball to roll off in all sorts of different directions. And if this is so, you can see that you could get a very large universe, and it would be split into a very large number of regions where the scalar fields would have differed, and as a result of this, the masses of the particles in those regions would have differed, the mass of the electron, the mass of the neutron, the mass of more obscure particles which you may not have heard of. All these masses could be different in the different regions of the universe.

22:30 And here we have a randomization mechanism which could lead to the existence, just by chance, of a few very rare regions of the total situation, the total cosmos, a few very rare regions where life is able to evolve. You'll tend to talk of these regions Which are different from one another as separate universes, but you don't have to. You can simply talk of them as separate regions. The Russians for years talked about meta-galaxies. They talked about our local galaxy and then the people who believed in... The large numbers of domains of the universe which were different in their basic characteristics would talk of these domains as meta-galaxies, but that has not spread to the West as a habit of speaking. Here are some of the claims which have been made about fine-tuning, and I do warn you that they are very controversial and that the force of the claims depends, I think, More on the fact that there's a very large number of them, and that they all have some plausibility, than on any particular claim on the list. Of course, you might want to say that since all the claims can be objected to on one ground or another, perhaps the whole lot is not very much worth having. There are some people who say that if you have a lot of sieves and they're all leaky, you're not going to be able to carry much water, no matter how many sieves you've got. Well, I've always thought, well, you can have quite a lot of water carriers as long as the holes in your buckets aren't too large. If you've got a lot of buckets and they're all carrying water, sooner or later you're going to get a lot of water across, you see. So I'm impressed by, as I say, the length of the list of things which you might want to claim have been fine-tuned by God or fine-tuned by cosmic randomization. So that life should become possible. Now, first, this came up yesterday, the question of the cosmic smoothness.

25:00 Roger Penrose suggested in his book, The Emperor's New Mind, that you could see the smoothness of the cosmos as tuned to one part in one, followed by ten to the power of one, two, three zeros. And all I can say is this is an enormous number. If you covered the entire surface of the Earth with zeros after the figure 1, you would still not have written down this number. You would only have written down a very small fraction of this number. It's a very large number. And the reason for writing down this number, which technicians will recognize as the Bekenstein found on the Kaltmarsch, is... That you would expect the universe coming out of the Big Bang to, you all know about the Big Bang since yesterday, to be built up of a very large number of regions which at early moments had not interacted with one another and therefore hadn't got their act together. Thank you for your attention and see you in the next lecture. It's not as if you'd have the Tremendous Heat very early and that would just die away or cool down. The Tremendous Heat would constantly be being generated by the fact that more and more regions which hadn't previously interacted would be coming over one another's horizons, would be seeing each other for the first time and they wouldn't have had time, they wouldn't have been able to get their act together and therefore they would be interacting in highly turbulent heat producing ways leading to cosmic chaos. Now, in fact, we don't see that. In fact, the universe is considerably smoother than a billiard ball, for example. This is an image which has been used by the cosmologist Peebles. P.J. Peebles says the universe is much, much smoother than a billiard ball.

27:30 The amount of smoothness of the universe is given by this sort of figure, tuning to one part in 10 to the 1, 2, 3, and Penrose has in his book a diagram of God with a huge space of possibilities and God has a pin with which he picks a particular possibility, and Penrose says that if this was what was going on, God would have to place the pin with this degree of accuracy. It's a degree of accuracy much greater than would be required to hit a particular fly at the other side of the galaxy with your high-powered rifle. That would be a much, much smaller degree of accuracy than what would be needed by God in putting his pin in place. Well, Penrose effectively says, I'm not going to believe in a huge number of universes in which this happens just by chance in one universe. He says that you get the universe which is tuned in this particular way just by having sufficiently many of them and giving them different characteristics. He says I'm not willing to do it by that route, nor am I willing to say that God did it. So I'll just say it's a basic principle that the universe has to be very, very smooth. And then he dresses up this basic principle with the technical terms. And as far as I can see this is just giving a name to the mystery. There's no particular reason why Penrose is willing to deal with the cosmic smoothness just by making it a basic principle, it's just that he doesn't like the God hypothesis, he doesn't think that God should be brought in at this level to explain what's going on, and he's not particularly keen on the multiple universes hypothesis which tells you that sooner or later you get the required degree of cosmic smoothness. Now, some people have argued against Penrose that actually the cosmic smoothness is given you by the inflationary theory which I've mentioned earlier, and this is one way in which this sort of claim which I've just made can be attacked. According to the inflationary theory, you could get a very small region in which the particles that got there act together, so that they all were behaving in an orderly way. And then this very small region could be inflated to such a size that it now stretches way beyond our cosmic horizon where right deep inside the region there's no way in which we can see the edges of the region.

30:00 And some people say that this would be an adequate explanation for the cosmic smoothness. You can imagine yourself with a very crinkly balloon which has been heavily inflated and the crinkles will tend to be smoothed out. The crinkles would originally look under high power like a series of mountains and valleys, but when the balloon has been inflated very much, then you get the... The smooth surface of the balloon replacing the earlier crinkles and some people have thought that if you have enough inflation going on then this gets rid of this problem of the cosmic smoothness. This is a technical matter. They haven't persuaded Roger Penrose. Roger Penrose is a top mathematician and physicist and so on. But he may be wrong. Nobody really knows who's right on this matter. Again, there's the question of the early expansion rate. The universe, in order to produce galaxies, and it's plausible that galaxies are needed in order for there to be life, in order to produce galaxies, the universe has to come out of the Big Bang in such a way that it's almost re-collapsing. And there will be then regions which do re-collapse which are the galaxies. That's to say they re-collapse sufficiently for there to be formed stars and planets and so on. It would seem that if you just look at general relativity's equations that your average universe would not do this sort of thing. Your average universe would either re-collapse after a very very short time I have my diagram here with the time of the universe size. Your average universe could be expected to re-collapse very, very quickly or else very, very rapidly to expand in such a way that it soon became very, very hard vacuumed as all the particles would be immensely far spread out and you wouldn't get any galaxies forming. You have to get the expansion speed just right. In order to avoid these two disasters, disasters from the viewpoint of life, the disaster of the universe re-collapsing after 10 to the minus 42 seconds, something like that, which is 1 divided by 1 followed by 42.

32:30 42 zeros, a very small fraction of a second. You could expect the universe to re-collapse, or you could expect it to just fall apart at a tremendous speed, no galaxies forming, unless you get the expansion rate attuned exactly rightly. In his recent book, Before the Beginning, the astronomer, Royal Martin Rees, compared the business of getting the expansion rate right to standing at the bottom of a well and throwing a stone upwards. So that it just stopped rising at the very top of the well. And that's a very difficult trick to perform. But actually this is, the trick is much harder to perform than that. A better image would be standing at the bottom of Mount Everest and throwing your stone up so that it stopped at the very top of Mount Everest. But even that wouldn't be good enough. The expansion rate has to be, it seems, tuned at early moments to something like 1 part in 10 to the 60, 1 part in 1 followed by 60 zeros, which is a very big number. But some people think that the inflation rate hypothesis can deal with this problem. They think that you look at the equations, you see that a If you have a heavily inflated universe, it's like a heavily inflated balloon. The surface of the balloon locally is virtually flat, and the equations tell you that a virtually flat universe is going to be expanding at just the right speed for galaxies to form. It's always going to be hovering on the brink, so to speak, of re-collapse, and that's what you want for galaxy formation. So, it's possible that the inflationary problem will get rid of both the problem of the initial expansion speed being exactly right for galaxies to form and also the problem of the cosmos being smooth enough that you don't have absolute chaos and searing heat which would exclude all life. The cosmic smoothness, the expansion rate, these might be fixed if you can get inflation to work, but then some people say that for inflation to work, you need to fine-tune what drives the inflation, which is an effective cosmological constant, and George Ellis, who by

35:00 Perhaps a fluke happens to be a leading Christian apologist who wants to understand cosmology very largely in terms of divine action. He thinks that to get inflation to earth you have to fine-tune this cosmological constant to one part in 10 to the 50. So he thinks that you can't get rid of your first two problems by bringing in this inflationary theory because the inflationary theory just sets up the third problem. This is typical of what's going on in this field. When you get the various claims made about how clever God has to be in order to get the universe working in such a way that life will come about, some people will say, well, no, God doesn't have to be clever at all. The whole thing is dictated. You'll even get some scientists trying to say there's only one possible universe. And God then, if he's going to create anything, has got to create that. That has been taught by some rather influential scientists, and this is an idea which was taught by Albert Einstein, for example. Maybe he's speculated there's only one way in which God could have created the universe. Other people think that a large number of numbers which seem to be coming into our formulas could take more or less any values and that God has done a good job or else you have an enormous number of universes with randomization of these numbers and then sooner or later you get the right mixture of numbers for life to be able to evolve. Here's another impressive number, the ratio of the strength of gravity to that of electromagnetism. Electromagnetism is about 10 to the 39 times stronger than gravity. And you know this by experience. If you want to get your hair to stand on end, you just can produce a very small electric charge in your comb by brushing it against something, and then you can put your comb above your head and your hairs will stand up. That tiny electric charge you put on the comb is counteracting the gravitational pull of the entire Earth. Gravity is really a very weak force, very much weaker than electromagnetism. It seems that you have to tune gravity to electromagnetism to one part in 10 to the 40

37:30 in order to get long-lasting, life-encouraging stars. And the reason for this is basically that stars can be of three sorts. I'm vastly simplifying here, okay. But vastly simplifying, a large number of the stars fall into three sorts. Stars like our sun, the red stars, and the blue stars. The blue stars are very much hotter than our sun and a typical blue giant will last for something like a million or a hundred million years, something like that. And that doesn't seem to be long enough for life to get going. A red star, there are various reasons for thinking that around a red star you're not going to get light forming because, for one thing, the individual particles of light aren't going to be packing enough punch. As you know, in a photographer's darkroom, the photographer can use red light and it doesn't affect the photographic film. It would be hard to see how anything like protopinthesis would get going around a small red star. And it can seem that in order to get a yellow star, in order to get any high portion of yellow stars like our sun, Yellow-white stars. You are going to have to get the correct ratio between gravity and electromagnetism into the form into the formula for calculating how the star will behave. One of the one of the numbers appears raised to its 12th power. Let's say it's raised It's multiplied by itself 12 times, so that any slight change in this number will lead to very great differences in how the star behaves. And this is the basis of the claim which is made by Paul Davies on the basis of calculations from others, I think, that the tuning of gravity to electromagnetism has to be one part in 10 to the 40 in order for there to be stars like our Sun. Okay, well, there are a lot of other claims about fine-tuning, but I have no time to go through them all. That's just a typical sample. It's thought that if you don't get the super-heavy particle masses tuned rightly,

40:00 then, for example, it will all of us be strongly radioactive, because our... The protons in our bodies would be constantly breaking down, and presumably if we were all strongly radioactive, well, we wouldn't be here anyway. No chance of our existing. In dealing with this sort of area, I have debated a number of stories in order to help persuade people that maybe there really is something which needs explanation. My first story is the fishing story. It's about a fish which has this length 23.2576 inches and you pull the fish out of the lake and you measure it and you see that's the length. What's so special about that? Every fish has got to have some length, no doubt all sorts of very special conditions are going to have to be satisfied for a fish to have this particular length. That's not going to be anything remarkable until you find that your fishing apparatus can only catch fish of this length plus or minus one part in a million. And then you've got a problem. And you've got a problem because you have two solutions to the problem which are attractive. This is a difficult point I'm going to go through it again in a moment. The reason you've got a problem is that you've got some solutions. Created that fish, made it exactly the right length for you to catch, because that person wanted you to have fish for dinner. There is a benevolent fish creator who has created the appropriately length fish for you. And the other possible solution is there are millions of fish in the lake and they've been swimming past your fishing apparatus. Sooner or later a fish of the right length comes along. That's the fish you caught. Now why do I say that this is an illustration of the principle that the reason why you have a problem is that you've got solutions. Well I think this is a case of the merchant's thumb principle in action and here I'm influenced by a story of Ernest Brahma, one of the Kailun stories and in this story they feature their character called Mok Cho who has sold

42:30 A silk robe to somebody, and his thumb has been concealing a tiny hole in the silk. So he has a silk robe, which is faultless. It's part of this little tiny hole, which would reduce the value by, you know, nine tenths, which is a very important robe. It's a funeral robe, you know. You do want to be buried in the right sort of robe, otherwise you don't get life. And his thumb has happened to be over this hole in the silk when he's displaying the robe. The charitably disposed were inclined to say that everybody's thumb has to be somewhere. However, the fact that it's over the hole in the silk suggests an explanation, and the fact that it suggests an explanation suggests that there really was a genuine problem. I think that this is what's going on in this area. But we see attractive explanations as to why the universe should be fine-tuned in such a way that life is able to evolve. One of them is the God explanation. God wanted life. He didn't want a lifeless universe. Our point of creating a universe was to have companionship or whatever, you know, and therefore God fixed it that nature would have all its numbers in the correct places for life to be able to evolve. That's the one approach. The other approach is the observational selection effect approach, which corresponds to there were lots of fish in the lake but I couldn't observe any fish which wasn't the right length for my fishing apparatus. The observational selection effect approach is that you have this huge number of universes, you have the force strength, the particle masses, various other crucial numbers randomized over these universes, and you, living beings, have to find themselves in the sort of universe in which everything has come out rightly. Well, I think that the Merchant's Sum principle, as I call it, is an important principle of reasoning. You all use it in everyday life. And it's a sort of principle of reasoning which should be relied on in this area. Before telling any more of the stories which I tell in this area, I ought to stress that this talk about fine tuning is meant to be talk of fine tuning not just for producing human beings, but for producing life of any plausible kind.

45:00 The suggestion is that if the universe had almost immediately collapsed, then it's unlikely that life would have evolved. This is, of course, by itself, it is a controversial suggestion because some people have been willing to speculate about very exotic forms of life. There's a wonderful book called Life Beyond Earth by Shapiro and Feinberg. I think it's one of the most beautiful books I've ever read, giving weird speculations about where you might find life in the universe. How about life in the sense of the sun, as was believed in, I believe, by William Herschel, one of the early astronomers, and even, by the way, Immanuel Kant in his early writings. He thought you could find life in the sun. Well, these days we think, oh, nonsense, you'd be fried, you know, no, don't look there. But the suggestion which is played by Weishaupt and Feinberg is that you have life based not on chemistry, but...