Tuesday, August 10, 2021

The interaction problem with substance dualism

The major difficulty with substance dualism is the interaction problem. This is the problem of accounting for how something physical and something non-physical could interact with each other. This problem is characterized in various different ways. If substance dualism is true, then the mind/soul has causal influence over the brain (which is how you are able to will your arm to move or act on any of your desires), and the brain has causal interaction with your mind/soul (which is how you are able to perceive through your sensory organs).

I came up with a solution one time that I have since then abandoned, but let me tell you about it. My solution was to say that maybe the mind has the unique ability to create energy ex-nihilo. Let me explain how I thought this could solve the interaction problem.

Imagine you've got some particle at rest, and you want it to move. Well, if that same object began to move, then it would have to have kinetic energy that it didn't have before, and that energy would have to come from somewhere. In the case of physical causation, energy is transferred to the particle by something else that has energy. Maybe something collided with it, or maybe it was pushed. But something that is non-physical doesn't have energy because energy is a physical thing. So it would appear to have no way to move the particle unless it had the ability to create energy ex-nihilo. So imagine that it could create another particle. All it would have to do is create the particle in proximity to the other particle, and the forces of nature could take over from there. If both particles were electrons, then there would be a force of repulsion between them. The direction of motion could be determined by the location of the created particle in relation to the already existing particle.

The causal interactions in the brain could be so subtle as to be unobservable or indistinguishable from random quantum events. One new electron could be sufficient to set of an avalanche of chemical reactions in the brain resulting in behavior. It might only require the release of potential energy through the pulling of a trigger.

I liked this solution when I first came up with it because it had a second use. In the Kalam cosmological argument, you get an immaterial cause of the universe, but then you need additional arguments to show that it's a person. William Lane Craig has two arguments for the personhood of the cause of the universe, and I don't think either one is all that persuasive.l But if it turned out that minds had the unique ability to create ex-nihilo, then we could argue for the personhood of the cause of the universe by saying something like this: Since minds are the only things we know of capable of creating ex-nihilo, it follows that a mind is the best candidate for an explanation for the beginning of the universe.

The only problem is that this solution only works when the direction of causation goes one way. It doesn't work as well when causation goes in the other direction. It explains how a mind could have causal interaction in the brain, but not how a brain could have causal interaction over the mind.

One possible solution was to imagine that the reverse happens. When the brain causes something in the mind, it does so by annihilation rather than creation. I don't think this works, though. It would require that matter has the ability to annihilate itself, but only when interacting with the mind. That just seems unlikely. You can't attribute the ability to the mind since that would require that the mind was doing the causing. We are trying to explain how the brain can do the causing, so it's the material of the brain that has to bring about the annihilation. Maybe somebody else can toy with that idea and make it work, but I don't see how it would work. It is for this reason that I've pretty much abandoned this whole solution to the interaction problem.

Currently, I have no good solution to the interaction problem. But the interaction problem isn't a major obstacle to my belief in substance dualism for a few reasons.

One reason is because in spite of the difficulty of solving the interaction problem, the arguments for substance dualism seem sound to me. If I were to give up substance dualism, I'd be trading one problem for even more problems. I think physicalism and idealism are even more problematic than substance dualism.

Another reason is because we don't have to know how something happens to know that it happens. There are mysteries in the physical world that we don't deny in spite of how strange they are. I'm thinking particularly about quantum entanglement. If two particles are entangled, then no matter how far apart they become, measuring the properties of one appears to determine the properties of the other. There appears to be instantaneous causation over large distances, or what Einstein called "spooky action at a distance." We know that it happens, and it's very strange, but we have no idea how it happens. If the world is strange enough to contain phenomena like this, then the interaction problem shouldn't bother us.

Lastly, it isn't as clear to me as it is to others why the interaction problem is a problem in the first place. I mean I do see that there's a problem. I just don't think the problem is as formiddable as some people think it is. That may be due to my own lack of understanding, but I can't help that.

Monday, August 09, 2021

Fine tuning, the anthropic principle, and the puddle analogy

According to the fine-tuning argument, the fact that there's this universe in which various constants had to have very precise values in order to make life possible requires an explanation which can be found either in a cosmic engineer (which would pretty much have to be a god) or a multiverse (which expands our explanatory resources). Some people say that fine-tuning can be answered by appeal to the anthropic principle. The anthropic principle is a particular manifestation of the observer selection effect. In this case, we would have to find ourselves in a life-permitting universe since a universe would have to be life permitting in order to contain us. We couldn't very well observe ourselves in a universe incapable of supporting life. So there is an observer selection effect that makes it possible to only observe life-permitting universes.

Some people think this answers the fine-tuning problem. Since we could only observe a universe that is life-permitting, it shouldn't be any surprise that that's exactly what we observe. Therefore, there's nothing that requires explanation.

The problem, though, is that the anthropic principle only works if you also invoke a multiverse. If there were a multiverse, and we were asking why we observe a life-permitting universe instead of a life-prohibiting universe, the anthropic principle would answer that question. Even if life-permitting universes are rare in the multiverse, they are nevertheless the only kinds of universes that can be observed since they're the only kind that can support observers.

But the question raised by the fine-tuning argument isn't why we find ourselves in a life-permitting universe instead of a life-prohibiting universe. Rather, the question is why we find ourselves at all given how unlikely it is that a universe that could support us would exist.

Consider the firing squad analogy. I got this from somebody else, but I don't remember who. Sorry about that. Anyway, imagine you're in front of a firing squad, and after they all fired, you're still alive. That requires some explanation. Why are you still alive? It wouldn't do to say, "Well, there's nothing here that needs to be explained since I would have to be alive in order to be asking the question." That doesn't answer the question. The question isn't why you're in front of a missing firing squad instead of a hitting firing squad. The question is why you're still alive at all since the probability was against you.

The puddle analogy is kind of like the anthropic principle. The puddle finds itself in a hole that seems perfectly suited to it. We know, however, that it's actually the puddle that has conformed to the hole rather than the hole that just happens to be suited to the puddle. In the same way, a lot of people say the universe wasn't made for us; rather, we conform to the way the universe already was. We are the way we are because the universe was the way it was, so there shouldn't be any surprise that we find ourselves in a universe that's perfectly suited to our existence.

It's certainly true that we have come to conform to the way the universe actually is. But remember, the fine-tuning argument isn't about why life turned out one way rather than another way. Rather, it's about why there's life at all, or why the universe is life-permitting at all. In the puddle analogy, the question shouldn't be why the puddle and the hole are perfectly suited for each other, but why a hole should exist at all that could contain a puddle.

The puddle analogy is similar to another objection to fine-tuning which is just based on a misconception about the fine-tuning argument. Some people take the fine-tuning argument to be about life as we know it. The assumption behind this misconception appears to be that if we just tweak the constants a little, we'd get a different kind of life. But that isn't the claim. The claim, rather, is that without fine-tuning, no life whatsoever, be it ever so exotic, would be possible since life of any kind (or at least any physical kind) requires complex chemistry, and complex chemistry requires fine-tuning.

Sunday, August 08, 2021

What did Jesus say?

This morning (8/7/2021), I was talking to a couple of family members about houses on beaches. I asked how they built them or what they did for a foundation since they were on sand. One of them explained how they drive beams or poles deep into the ground until they hit some kind of solid foundation. The conversation reminded me of what Jesus said in Matthew 7 about building your house on the sand. He said,

Therefore, everyone who hears these words of Mine, and acts on them, will be like a wise man who built his house on the rock. And the rain fell and the floods came, and the winds blew and slammed against that house; and yet it did not fall, for it had been founded on the rock. And everyone who hears these words of Mine, and does not act on them, will be like a foolish man who built his house on the sand. And the rain fell and the floods came, and the winds blew and slammed against that house; and it fell—and its collapse was great. ~Matthew 7:24-27

I read this to the said family members as kind of a joke, inserting "tsunamis" along with the wind and rain. They were talking about buying a house on the beach, and the joke was that Jesus said only a fool would build a house on the sand. One of them wanted to challenge whether Jesus actually said it, so first he asked who wrote it, and then he asked when it was written. I didn't go into detail about that, and it's beside the point of this post anyway. This is just a preface to explain what got me to thinking about what I'm going to say in this post.

The point of this post is to talk a little bit of what I think about whether and to what degree the gospels accurately portray what Jesus said. I only want to speak in generalities here because otherwise this would be really long. Besides, I haven't done an in depth study on the sayings of Jesus, and I'm probably not qualified to do that anyway.

But I can talk in generalities, and I have just a handful of points I want to make. I want to talk a little about what we should expect of the gospels and also what the gospels actually show.

First, Jesus was an itinerant teacher. Like most traveling teachers we know of (e.g. Christian and atheist apologists), they give a lot of the same talks over and over again or they repeat the same things over and over again in their various talks. If you follow certain people, you begin to pick up on speech patterns, aphorisms, and one-liners they use. A person can be famous for a quote or two, and that quote gets repeated by their followers and even by people who don't follow them. We should expect that the same thing would be true of Jesus. Jesus likely had very devout followers--people who looked up to him in a way that nobody looks up to Richard Dawkins, Christopher Hitchens, or William Lane Craig. So we should expect that many of them hung on his every word. They followed him from town to town, hearing him say the same things over and over again. Some were part of his inner circle who eventually became apostles who then repeated those teachings to other people. So we should expect that at least some of the sayings of Jesus in the gospels would be almost verbatim what Jesus said. This would be true even if people didn't intentionally commit their teacher's sayings to memory. It would just stick as a matter of course.

That is probably the case in some of the more pithy sayings of Jesus as opposed to the long monologues. But we also see certain speech patterns that are peculiar to Jesus, like how he says, "truly truly I say to you. . ." or how he talks about the Son of Man in the third person even though it appears he's always talking about himself in those sayings. Jesus has a certain voice. We recognize "voice" in people we know really well. So if somebody were to try to fake a letter from your wife to you, you might read the letter and think, "That doesn't sound like how my wife speaks or writes."

Contrast that, though, with John's gospel. In John's gospels, the voice of Jesus often sounds more like the narrator than like the Jesus of the synoptics. I'll come back to this point in a little bit.

There are other reasons besides having a peculiar voice to think some of the sayings of Jesus are nearly verbatim when recorded in the synoptics. One is that they are multiply attested. For example, sometimes when Jesus tells a parable, he'll preface it by saying, "The kingdom of God is like. . ."

If you look at the synoptic gospels in parallel, you notice that while he might say the same things in similar words, the exact wording is often altered. This can be attributed to a combination of two things--Jesus himself likely altered the way he said things in different places and in different contexts, and the authors themselves might've altered the way Jesus said something to fit the context.

That brings me to another point I wanted to make which is that I definitely don't think everything the gospels quote Jesus as saying is verbatim what he said. I think in a lot of cases, especially in the longer monologues, they are trying to capture the gist of what Jesus said or taught. Returning to what I said earlier about John's gospel, I think John does this more than the synoptics. If Jesus himself varied how he delivered certain teachings, there's no reason for why the gospels authors shouldn't do the same.

There is a question, though, of what they intended to accomplish. Were they attempting to capture Jesus' sayings as accurately as they could, were they happy to capture what they took Jesus' teachings to be, but put them in their own words? Or were they making stuff up, maybe to attribute things to Jesus that they themselves already believed?

This can be partially answered by looking at the genre of the gospels, which is Greco-Roman biograpy. I've become so convinced of this position over the last year that I've decided to just state it as a fact rather than hedging by saying, "According to most scholars," or citing Richard Burridge. Anyway, Greco-Roman biography covers a wide range of styles. According to some ancient historians, the goal ought to be to capture the essence of what somebody said in a speech, but you ought to do it in an artistic way. I think John took more artistic license than the synoptics, but I think John accurately conveyed what Jesus taught. I am an inerrantist after all.

My suspicion is that once some saying of Jesus was committed to writing, authors who used that writing as a source took less artistic license than they would have if they were writing a completely fresh gospel. So Mark might have taken some artistic license in how he conveyed Jesus' teachings, but once he did, Matthew and Luke only altered them slightly. And I don't really know how much of that alteration is due to the artistry of Matthew and Luke or due to the fact that Jesus himself worded things differently from time to time. Even if Matthew and Luke were writing independently of each other about the same event, they might have worded things differently because nobody knows which way Jesus said a particular thing in one place as opposed to another place. If he said the same thing in slightly different words in Capernaum and Bethsaida, it could be that nobody remembered which way he said it in which place. But it doesn't matter unless the difference in wording fits the context better in one place than in another.

I suspect that in at least some Greco-Roman biography, authors made things up. In some cases, they might make up a speech to capture a moment that they think would've been appropriate for the occasion. Or maybe they went so far as making stuff up because it's what they wish the person had said. If I were looking at the gospels from a purely secular perspective, I wouldn't rule out that possibility in the case of Jesus either. But because I think the gospels are the word of God, I think that puts limits to how loosely they could have been written. I don't think, for example, that the authors would have Jesus saying something when Jesus never said any such thing, and I especially don't think they'd have Jesus saying something if it were actually contrary to something Jesus taught.

But even from a secular perspective, there's another reason to think the gospels accurately capture at least some of Jesus' teachings besides the fact that he was an itinerant teacher and is portrayed as having a peculiar voice. It's because it seems very unlikely that a religion that grew up around his memory would end up having nothing to do with the real Jesus. While a secular person might allow that legends grew up around Jesus, it's highly unlikely that the movement he started would diverge so thoroughly in such a short amount of time (especially during the lifetime of his apostles) that nothing of the real Jesus survived, and all of it was completely replaced by fiction. I wouldn't believe that no matter how anti-Christian I was. I would think the gospels must retain at least some of what Jesus said and did, especially the really important stuff, and I would think one could apply historical methods to discover at least some of the authentic teachings.

That is not to say it would be easy. If you look at the history of historical Jesus studies, you see that consensus is hard to come by. In spite of that, there is consensus on at least a handful of things. The Jesus Seminar attempted a few decades ago to see if they could reach a concensus, and they did reach a concensus on about 18% of the sayings of Jesus. They've been criticized as not being representative of scholarship as a whole, but if the critics had their way, that concensus would be higher, not lower, because the dispute wasn't in what the Jesus Seminar affirmed, but in what they denied.

Saturday, August 07, 2021

Entropy, fine-tuning, multiverses, and Boltzmann brains

I got my car inspected this morning, and as I was waiting in the waiting room and looking at the TV, I got to thinking about the pixels and how one time I had looked at my iphone screen through a pocket microscope and seen a bunch of small squares coloured red, green, and blue. I imagined that the TV screen was built the same way and how any image you might see on the TV could be formed from just those three colours.

Then it hit me how this could be used as a perfect analogy to talk about entropy, probability, and one of the first objections I had to teleological arguments.

I was first introduced to "the" teleological argument in my freshman philosophy class in the spring of 1997. At the time, I thought the teleological argument was the weakest argument for God because whereas the other arguments were deductive, the teleological argument could only give you a probability. Supposedly, life was improbable because, like a watch, it required a specific arrangement of parts in order to function. My main objection to this argument was that any arrangement of parts you could think of was equally improbable. I remember using this analogy: If you were to toss up a handful of pennies, no matter how they land, that arrangement will be extremely improbable. Yet there's nothing remarkable to be explained since they had to land some way.

The mistake in my argument was in thinking of each possible arrangement in isolation. The reality of the matter is that there are different kinds of arrangements, and what's improbable is that any given arrangement will fall within a certain kind. I don't know why this wasn't more obvious to me back then because it's so plainly obvious to me now. Anyway, let me use the TV analogy to explain myself while it's fresh on my mind.

Let's imagine the TV screen has 1080 pixels, and each pixel can be either red, green, or blue. So there's three possibilities for each pixel, and we want to know how many possible arrangements there can be on the whole screen. To find that number, you'd have to multiply 3 by itself 1080 times. So, 3 x 3 x 3 x . . . equals 31080. That's an enormous number. I'm not sure how to convert it to base 10 because it's been too long since I took a math class.

[EDIT: I figured it out. You just set 31080 equal to 10x, and solve for x. You can take the natural log of both sides, which gives you 1080*ln(3) = x*ln(10), so x = [1080*ln(3)]/ln(10). If I did that right, then x = 515.29. That means 31080 = 10515.29, which is a big ole number. Somebody correct me if I did that wrong.]

[2nd EDIT: I guess it would've been simpler if I had used log instead of ln. It's just that I remember using ln to solve these kinds of problems back in the day. Anywho, carry on.]

Statistically, any arrangement is just as improbable as any other arrangement. If you were to randomly shuffle the screen, the probability of any given arrangement is 1 in 31080. Yet it has to land on some arrangement. So why think it's any more probable to get static noise than to get a recognizable picture of my cat?

The reason is because if you compare the number of arrangements that produce a picture to the number of arrangements that produce random noise, the noise-type arrangements vastly outnumber the picture-type arrangements. So it's far more probable that you will end up with random noise than that you will arrive at a picture. Never mind a picture of my cat. It's highly improbable that you'd end up with any picture.

So I was just looking at the wrong probability. The question isn't how probable it is that you'd get one particular arrangement instead of another, but how probable it is that whatever arrangement you got, it would fall within a certain kind. In the case of living beings, the question isn't how probable it is that you'd end up with a particular arrangement of molecules that makes a human being compared to any other arrangement. The question, rather, is whether you'll end up with the kind of arrangement the operates like a mechanical machine capable of performing some function instead of random noise or a puddle of homogeneous goo. There are certain kinds of arrangements that are special in some way, whether they produce a recognizable image on a screen, information, a machine, biological life, or whatever.

This applies to teleological arguments from biological life as well as fine-tuning. Of course in the case of biological life, there is a mechanism that makes it possible to arrive at improbable arrangements through a series of small steps. A lot of people hope that something similar will come along to explain fine-tuning.

One popular attempt to answer fine-tuning is to artificially increase our probablistic resources. Using the TV analogy, you can consider each shaking or random try as a probablistic resources. If you shook things up randomly 31080 times, you'd be practically guaranteed to get one of those special arrangements that produces an image of something. The more random tries, the more probable it is to get a special arrangement. In the same way, the more universes with randomly ordered constants there are, the more probable it is that you'd get one with just the right arrangement to make chemistry, and therefore life, possible.

The problem with taking this approach is that it creates the Boltzmann brain problem. This is where the TV analogy can be used to explain entropy. The second law of thermodynamics can be thought of in statistical terms. Given a fixed amount of energy (i.e. a closed system), there are many forms that energy can take and many different arrangements it can be in. Take heat energy, for example. If you have a room with a hot end and a cold end, heat will move from hot to cold until the room reaches a state of equilibrium. Once the heat is equally distributed, the temperature will be the same everywhere. And once that happens, heat will no longer flow. Well, for energy to be used to do work, it has to be transformed from one kind to another or from one thing to another. Heat energy can be converted into mechanical energy, for example, in a heat engine. Mechanical energy can be converted to electrical energy in a generator. Electrical energy can also be converted to mechanical energy in a motor, or into heat energy on your stove.

This process is never done with 100% efficiency, though. In the case of the room whose temperature equalizes, you have just as much energy at the end of the process as you have at the beginning because it's a closed system, and the energy remains constant. But once equilibrium is reached, none of that energy is available to do work anymore. In the same way, when you convert energy from one form to another, there will be a certain fraction of that energy that is no longer available to do work. This is the problem with perpetual motion matchines. If you had a motor that turned a generator, that created electrical power to the motor to keep turning the generator, eventually, the whole system would reach a state of equilibrium. None of the energy would be available to do work, and the machine would shut down. When I was in the nuclear power school in the navy, we were taught the rule: "A heat engine must reject heat." That's because there's always going to be a certain amount of energy that can no longer be used, and if you have a closed system, eventually none of the energy will be available to do work anymore.

The amount of energy that's no longer available to do work is called entropy. Entropy can be thought of as the amount of energy unavailable to do work or as the amount of homogeneity of energy, or the spreading out of energy, or the degree of equilibriunm, or randomness, or whatever. They all amount to basically the same thing. The second law of thermodyamics says that the total entropy in a closed system (i.e. a system in which energy neither increases nor decreases, leaves or enters the system, etc.) will increase with every process. Basically, when anything at all happens in the universe, the total entropy of the universe increases. This is true even when it appears as if entropy had gone down. The reason is because if something becomes more ordered or arranged in such a way that energy can be used, the entropy will increase somewhere else. For example, when ice crystals form, it does so by giving off heat, and that heat dissipates in the universe, increasing the over all entropy of the universe.

So let's go back to the TV analogy. If you started off with a nice crisp image of a cat, and you shook it just a little, that image would be less crisp. And the more you shook it, the less you'd see an image, and the more you'd see randomness. The reason is because each time you shake it, it's going to end up in a less ordered state because disordered states are statistically far more probable than ordered states. Since the universe is in a constant state of change, the arrangement of particles is constantly changing. And since there are more disordered states than ordered state in all the possible configurations of particles in the universe, it follows that as the universe changes, its entropy increases. It would be mind-blowingly improbable for this process to ever reverse. And even if it did reverse for just a brief moment, it would immediately go back to increasing entropy.

Now let me explain how this applies to the multiverse solution to fine-tuning and how that creates the Boltzmann brain problem. Let's say that I shake the TV enough times that I create an image of a butterfly in some random place on the screen. The background remains random. Well, that is far more likely to happen than to have the entire background filled in with other butterflies and leaves, flowers, and stuff. So if we shook the TV, say 3100,000,000 times, you'd get far more screens with an image of just one butterfly and a random background than you would screens that were filled with butterflies, leaves, flowers, etc., and no random background.

Now, consider the universe. At the beginning of the universe, the total entropy was very low. It's been going up constantly for the last 13.8 billion years. The universe is approaching a state of equilibrium, and when it reaches that state, there won't be anymore life, stars, galaxies, etc. But we are far from there yet. There is still enough order in the universe to produce stars, galaxies, and biological life. But imagine if instead of an entire universe like ours filled with galaxies and containing as much life as there is on earth, you instead had just one sentient life form, and the rest of the universe was in equilibrium. Well, obviously, given the same amount of matter and energy, a universe with one life-form in a sea of equilibrium is statically far more probable than a universe full of stars, galaxies, and billions of life forms. It's just like how a screen with one butterfly in a sea of randomly ordered colours is more probable than a screen filled with images of butterflies and things. And just as shaking the screen a gazillion times would produce far more scenarios with just one butterfly and a random background than screens filled with butterflies and things, so also creating random universes would produce far more universes consisting of just one life form in a sea of thermodyamic equilibium than in universes like ours where the whole thing is full of order and consisting of billions of life forms.

What needs to be explained, though, is just the perception of a universe like ours. After all, it is from this perception that we draw all our conclusions about the universe. Presumably, if we want to assume physicalism, this perception is produced by our brains. So all you'd need to produce these images is a brain whose internal structure is exactly like the internal structure of a brain that is getting input from its sensory organs. And you really only need that brain to exist for a split second in order to explain your experience. After all, you only experience the present. It's possible you came into existence a split second ago complete with perceptions, beliefs, memories and everything, and if you really are just a brain floating in space, you're probably going to die in just a moment. The fact that you haven't already died only means you just now came into existence a split second ago.

Statistically, it is far more probable that a brain without a big well-ordered biologically complex body would spontaneously emerge in a sea of thermodynamic equilibrium than it would be that a whole universe like ours would spontaneously emerge if you were just producing random universes.

So if you appeal to a multiverse in order to explain fine-tuning, then you run up against the Boltzmann brain problem. A Boltzmann brain is an isolated brain that comes into existence complete with perceptions, beliefs, memories, etc., and it perceives a universe like ours. Since Boltzmann brains are vastly more probable than universes like ours, it follows that if we try to explain fine-tuning by appealing to the probablistic resources of a multiverse, there would be far more Boltzmann brains than there will be people living in universes like ours. With that being the case, it is far more probable that you are a Boltzmann brain than it is that you are living in a real universe that looks like ours appears to be.

You could respond to this by biting the bullet and saying, "Okay, so it's likely I'm a Boltzmann brain." After all, this argument is similar to the simulation hypothesis in the fact that we are comparing the number of sentient beings inside a simulation to the number of people in the real world. A lot of people think we are in a simulation because of this argument. If you click on the link, you'll see my reasons for thinking we are not in a simulation. One of those reasons is just an appeal to common sense realism--the view that we should take the world as it appears to be apart from any good reason to think otherwise. We have such a strong intuition that the world is real that we only pretend to take brain-in-vat type scenarios seriously. They're great thought experiments, but if we're totally honest with ourselves, hardly any of us really believe them. We have such a strong intuition that our senses are giving us true information about a real external world that we cannot bring ourselves to deny its reality even in the face of arguments (like Zeno's paradoxes) that we can't answer.

That's why Boltzmann brains are problems. If you have a model of reality that generates the Boltzmann brain problem, then that's a good reason to reject that model. You have to reject it on rational grounds because you probably don't think you're actually a Boltzmann brain. If we're going to be serious, we can't embrace models of the world that make it more likely that we are Boltzmann brains. So we have to reject any multiverse model that generates the Boltzmann brain problem.

There are multiverse models that don't generate the Boltzmann brain problem, but those models also don't answer the fine-tuninng problem. Maybe somebody will come up with a model that answers fine-tuning without generating the Boltzmann brain problem, but so far I don't know of such a model. Let me just mention a few I'm aware of.

First, there's the many worlds interpretation of quantum mechanics. This one doesn't explain fine-tuning because each branching universe has exactly the same values to its constants.

Second, there's string theory (or M-theory). This doesn't explain fine-tuning for two reasons. First, it doesn't predict a multiverse. It only makes a multiverse possible. The possibilities are limited to about 10500 because there are 10500 different possible spacial geometries, each producing a different configuration of constants. Second, if string theory did predict a multiverse, it would generate the Boltzmann brain problem because while these 10500 different kinds of universes are possible, the actual constant configuration of each universe is still random. It's random which of the 10500 possibilities any given universe will turn out to have.

Third, there's a model that I think is called the ekpyrotic model. I'm not 100% sure, though, because there's also the "eternal inflation" model, which might be the same thing, or might be a feature of the ekpyrotic model, or might be a different thing altogether. Anyway, according to this model, the whole of space is in a state of constant rapid expansion, and every now and again, some small bubble will come out of this rapid expansion and coalesce into a bubble universe. Ours is just one of them, which is why our current big bang model has an inflationary period at the beginning of it. When inflation ends in some bubble universe, it takes on a set of values for its constants. This model, too, creates the Boltzmann brain problem. It may also run up against the Bord, Guth, Vilenkin theorem, but I'm not sure.

Fourth, there's another model that's almost just like the inflationary model above except that there's no inflation. There's just an infinite sea of equilibrium that exists for infinity. Given an infinite amount of time, it becomes statistically probable that in isolated regions, you'll get a state of low entropy just by random chance, and our big bang was just one such state. This model obviously creates the Boltzmann brain problem.

There are other models. Some of them don't create isolated universes. Some of them create sequential universes, so they're not really multiverses by the usual meaning of the term. Instead, they are cyclic universes in which the same universe gets a fresh start multiple times. In Roger Penrose's cyclic model, I don't think the constants are different in each cycle, so it doesn't answer the fine-tuning problem. But if they were different each time, then it would solve fine-tuning, but it would create the Boltzmann brain problem.

I guess that's about all I had to say today.

Sunday, August 01, 2021

Don't lose your iPhone

The "find your phone" feature that exists in the iCloud used to serve a purpose. If you lost your phone, you could log in with your computer and locate your phone. I've used this feature before, and it was a big relief to have it.

But now they've rendered it useless by insisting on two-factor authentication. Now, if I want to log in to iCloud, they'll send a code to my phone which I can then enter on the web page to complete the log in. That doesn't help if I've lost my phone, which is why I was logging on in the first place.

I tried to shut it off, but I can't because it's mandatory. After googling around about the problem, I discovered that the only solution is to have a buddy who you can rely on in your time of need. You use their phone number in your iCloud so the code will go to them instead of you. Then they give you the code, and you can log in and find your phone.

Just one more reason to despise Apple. They giveth, and then they taketh away--like the mag safe charging port, the ordinary USB ports, and decent keyboards that work.