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Our future, our universe, and other weighty topics

Monday, January 22, 2018

Masquerade of the Multiverse Metaphysics

Physicist Sean Carroll has a new paper trying to drum up support for the multiverse, the groundless idea that there is some vast collection of universes outside of our universe. The paper is entitled “Beyond Falsifiability: Normal Science in a Multiverse.” 

In his introduction, Carroll states this:

Multiverse models are scientific in an utterly conventional sense; they describe definite physical situations, and are ultimately judged on their ability to provide an explanation for data collected in observations and experiments. But the kind of science they are is perfectly ordinary science. The ways in which we evaluate the multiverse as a scientific hypothesis are precisely the ways in which hypotheses have always been judged.

None of this is true. Specifically:
  1. Multiverse theories are not actually models. In scientific terminology a model is a simplified conceptual representation of a complicated physical situation. For example, the Bohr model of the atom involved a simplified representation in which the complicated reality in an atom was depicted like a simple solar system, with the nucleus being like the sun and the electrons like the planet. Instead of imagining something simpler than the known reality, as in a model, a multiverse is imagining some reality almost infinitely more complicated than our known observable reality.
  2. Carroll's insinuation that something is scientific because it describes “definite physical situations” is wrong. If I imagine there are mile-high dragons on the far side of the moon, I have imagined a “definite physical situation,” but my fantasy is not scientific.
  3. Typical multiverse assertions do not at all assert “definite physical situations.” Instead of precise descriptions, we get thinking along the lines of “maybe there are countless other universes, each with a different set of characteristics.” Such airy fantasies are not cases of postulating a definite physical situation.
  4. Science can properly be defined as either (1) the body of facts that have been established by observations and experiments; or (2) the activity of scientists gathering observations, performing experiments, and interpreting such results. According to neither of these definitions is the concept of a multiverse science. And it is certainly laughable to call this very bizarre and non-scientific idea of the multiverse “perfectly ordinary science.”
  5. We can hardly show that the multiverse is science by arguing that “the ways in which we evaluate the multiverse as a scientific hypothesis are precisely the ways in which hypotheses have always been judged.” You could use the same logic to argue that palmistry and magic spells are science, on the grounds that the way such things are properly evaluated is precisely the ways in which hypotheses have always been judged.
  6. Multiverse theories do not actually explain anything, and it is not correct that they are “judged on their ability to provide an explanation for data collected in observations and experiments.”

Carroll gets into a discussion of whether falsifiability helps us distinguish between science and non-science. Falsifiability means when we can imagine observations that might disprove a theory. Carroll tries to suggest that we should discard falsifiability as an acid test for whether a theory is scientific.

It is true that it doesn't make sense to say that distinguishing between science and non-science is as simple as asking whether a theory is falsifiable. There are actually perfectly reasonable scientific theories that could never be falsified, such as the theory that life exists on some other planet. Falsifying such a theory would require observing all of the planets in the universe within some short time period, which is physically impossible because of the vast number of stars that exist, and the difficulty of traveling between them. But the fact that falsifiability is not suitable as a sole determinant of whether something is scientific does not mean that we should go “beyond falsifiability,” and pay no attention to falsifiability.

A reasonable program for judging whether an idea is scientific would be to have a kind of six-point system in which multiple criteria were considered. It might work like this:

  1. Your theory gets one point if there are possible observations that could verify the theory.
  2. Your theory gets one point if there are possible observations that could disprove the theory (meaning the theory is falsifiable).
  3. Your theory gets one point if there is substantial evidence suggesting the theory is true.
  4. Your theory gets one point if there is not substantial evidence that the theory is false.
  5. Your theory gets one point if it makes precise numerical predictions that can be tested.
  6. Your theory gets one point if it is simple and economical, and consistent with the long-standing scientific principle of Occam's Razor, that entities should not be multiplied beyond necessity.

This type of evaluation algorithm makes sense. It includes the idea of falsifiability, but only as one of multiple things that will be considered. We may note that according to such a reasonable evaluation algorithm, the idea of the multiverse scores only one point (as does the theory that there is somewhere a planet ruled by purple unicorns). The only one of these requirements met by the idea of the multiverse is number 4: there is no substantial evidence that there is not a multiverse. The multiverse fails all of the other evaluation criteria. It certainly fails requirement 1, as there are no observations that we could possibly have that could show there are other universes. Anything we might observe in our telescopes would be something part of our universe, not some other universe.

Conversely, a real scientific theory will score at least 3 points under such an evaluation system.

Most absurdly, Carroll attempts to persuade us that postulating a multiverse would be a case of “inference to the best explanation,” sometimes called abduction. He states the following:

Abduction lets you go the other way around: if you get sick, and there are no other obvious reasons why, you might conclude that you probably ate some spoiled food. This isn’t a logically necessary conclusion, but it’s the best explanation given the context. Science works along analogous lines....The multiverse, therefore, is a case of science as usual: we evaluate it on the basis of how likely it is to be true, given what we know on the basis of what we actually have observed.

This comparison is highly erroneous, and calling a non-scientific multiverse fantasy “science as usual” is preposterous. In the case of drawing a conclusion about a stomach pain, the numerical reasoning occurs like this:

  1. We consider the most common causes for a stomach pain – what percentage of the time it is caused by food, what percentage of the time it is caused by cancer, what percentage of the time it is caused by a kidney stone, etc.
  2. If one of these causes is more common than any of the other causes, we might deem that as the best explanation.

But no such reasoning can possibly can go on in regard to a multiverse. For we have no data at at all about anything caused by a multiverse, nor do we have any evidence that a multiverse exists. So there can be no “inference to the best explanation” comparable to what goes on in assuming that a stomach pain was probably caused by food. Inference is based on observations, and there have been no observations about a multiverse – no observation of other universes. It is wrong for Carroll to claim that a multiverse theory is evaluated “on the basis of how likely it is to be true, given what we know on the basis of what we actually have observed.” To the contrary, multiverse theories are speculations involving other universes very different from those we have observed. 

 There is a perfectly good term that has been used for centuries to describe speculations about that which is not observable. The term is metaphysics. Metaphysics is what is going on when you speculate about the nature of God, angels, life after death, and unobservable universes beyond our own. Multiverse speculations are properly classified as metaphysics. A multiverse speculation isn't science, which is properly defined as facts established by observations and experiments, or the activity of making observations and doing experiments that try to establish facts (or interpreting such observations and experiments). If you try to put a mask of science on the multiverse, such a ruse is best described as a masquerade. A multiverse speculation masquerading as “perfectly ordinary science” is as outrageous an impostor as some escaped convict masquerading as a doctor by putting on a white coat and a stethoscope.

Thursday, January 18, 2018

I Thought It Was a Nuclear Bomb Exploding

Recently people in Hawaii had a nuclear scare, as a false alert went out warning of an incoming missile. Those to blame for this event include a person operating a computer system, and the designers of the computer system, who made it too easy for such an operator to make a mistake. The incident reminded of the time I thought I was actually witnessing a nuclear bomb going off.

I have lived through two different terror bombings of the World Trade Center in New York. The first occurred on February 26, 1993 at 12:17 PM. I had a 12:30 lunch date with the woman who was then my fiancee and is now my wife. The lunch date was in the Sbarro's restaurant on the ground floor of the World Trade Center.

What occurred was an interesting illustration of how people will misidentify something they have never seen before, interpreting it as something they have seen before. Upon entering the World Trade Center, I saw a huge cloud of dust in its halls. The bomb had gone off a few minutes before I came in. At this time almost no one was thinking about any chance of terrorism in New York. So I did not at all think to myself: this must be a terrorist attack. Instead, I said something like, “Wow, I can't believe how careless those construction workers were – look at all the dust they kicked up.” Even with this huge cloud of dust in the halls, the food servers at Sbarro's kept trying to do their jobs. The police then told everyone to leave the building.

The first bombing of the World Trade Center did relatively little damage. People kind of said, “Those clumsy terrorists – their attempts at destruction are a joke.” Only a few years later, the people at the company where I was working had the idea of moving to a new building, and they chose the World Trade Center, which would turn out to be a horrible mistake. It's amazing how everyone paid little attention to a threat that had been clearly announced by the 1993 bombing.

I got into work at 7:00 AM on the morning of September 11, 2001, and took the elevator up to the fortieth floor of the World Trade Center. I was completely absorbed in what I was doing on my computer when the first hijacked jet liner crashed into the building. There was a very loud noise, and a tremendous jolt, like some giant hand was shaking the whole building.

I jumped up to look out the window, and then immediately saw a huge fall of flaming debris. It looked rather like a huge chunk of the upper building was collapsing in flames. Terrified, I yelled at the top of my lungs, “Get the f*** out!” I then ran for the stairs.

As I started to run down the stairs, I had a fleeting thought that a nuclear bomb had exploded. People had long feared that someone would sneak a small nuclear bomb into the city. What I had witnessed up until this point was consistent with a small nuclear weapon going off at ground level.

My chances looked good after I had passed down a few flights of stairs. There was no one in front of me. Then I encountered some smoke on the stairs. I remember thinking: this is it, I'm going to die. But the smoke cleared as I passed down several floors lower. At some point I encountered lots of water pouring out into the stairway. But after passing down a few more floors, I passed through the part that was flooded.

Eventually the stairs started to fill up with people exiting the building, and the stairways become clogged with people. The downward flow of people stopped entirely. I thought to myself: what could be causing the delay? It turned out to be a delay caused by people letting firefighters walk up the stairs. What went on at this time made no sense from a safety standpoint. No one should have tried to walk up the stairs until they had become uncrowded, so that as many people as possible could have exited. I will never forget the worried, tired look of the brave firefighters as they walked up those stairs. Many of them never made it out.

Finally, after about 20 minutes, I got down to the ground floor. I was now in the elevator lobby of the World Trade Center. I looked in amazement at one of the elevator entrance doors. They were all charred and black, as if someone had torched them with a flame thrower. This could have been flames traveling down the elevator shaft.

I made it into the shopping mall area of the World Trade Center, and was drenched by sprinklers that had been activated by the fire. Finally I made it out of the building. When I looked up at the top of the building, I saw a huge column of black smoke rising up from the top of the building. I walked home all the way from lower Manhattan to the Jackson Heights neigborhood of Queens. While passing around the Times Square area, I saw some giant TV screen showing the World Trade Center buildings collapsing. I was dumbfounded. I thought the buildings would last for a thousand years.

I knew one person who died in the attack, a very smart young man named Scott. Scott first appeared on our work scene in a rather lowly position, but later I overheard him interviewing for a programming position in a cubicle near mine. I was amazed by what I heard – it was like he had an encyclopedic grasp of the technology we were using. I wasn't surprised at all when he was hired as a programmer, nor was I surprised when he started rising up in the company as a technical manager. Apparently he had risen rather high in the company by September 11, 2001, for he worked on one of the high floors of the World Trade Center where pretty much only the upper echelons worked. It was, tragically, a case of rising too fast and too high in the organization, because nobody on those highest floors of the World Trade Center made it out.

They have made an impressive memorial to those who died in the World Trade Center attack. It is a beautiful and dignified monument. But in a book of alternate designs submitted for the memorial, I saw a design I liked a lot more. The design proposed a structure consisting of thousands of suspended bells, each with the name of a person on it. The great thing about such a design is that it could have turned the World Trade Center area from a place of sorrow to a place of joy – because children would have taken great delight in ringing all the suspended bells. 

Memorial at the World Trade Center

Sadly, there is a substantial risk of another terrorist attack, perhaps one much worse than the September 11 attacks. The problem is that the materials to make nuclear bombs are scattered all over the world. If you are in a skyscraper, and you ever think a nuclear attack has occurred, don't look out the window like I did – for it could be a flash that could blind you. Instead, run for the stairwells, and try to stay there as long as you can, doing what they call “shelter in place.” The area inside a stairwell of a skyscraper offers excellent shielding against radiation. The radiation from a nuclear bomb would decrease by about 50% every day. So anyone willing to wait several days in a stairwell could then emerge into an environment with much less radiation.

Monday, January 15, 2018

Pom-Pom Journalism of the Mainstream Science Writers

There is a certain viewpoint about US Presidents and military actions that cheerleaders for the President and the military like to present. The viewpoint is a kind of rose-colored viewpoint that is highly idealized. Below are some of the ideas that we might find in such a viewpoint.
  1. The President of the US always acts as a benevolent or fair figure who metes out kindness or justice to foreign nations.
  2. If a US president ever decides to take military action against a foreign nation, it is because he was forced into such an action, and such a nation (or people in it) deserved such a response.
  3. The US president never authorizes or continues military actions mainly or largely because such actions might benefit himself, his friends, or his party.
  4. Once the US military has been ordered to engage in military action, they engage in this violent activity with great reluctance, and take great care to minimize enemy deaths and civilian deaths.
  5. The military acts to keep any military engagement as brief as possible, and keep US soldier deaths to a minimum.

But sadly a great deal of historical evidence argues against this idealized outlook, and favors a more realistic outlook. If you take a close historical examination of the US military actions in places such as Vietnam, Iraq, Cambodia, and the Philippines, you might adopt a very different perspective with some of these ideas:

  1. The President of the US often initiates or continues military action largely for selfish reasons, to benefit himself, his campaign donors, or his political party – partially to make himself look strong or decisive or heroic, in a way that improves his election prospects, and partially to help corporate interests that may contribute to his re-election campaign.
  2. A US president may decide to order US military force when no such action is forced on him, and no such action is deserved by the nation that suffers from the military action.
  3. Once they are ordered into action, a very tiny fraction of the soldiers in the US military may proceed with excessive brutality, having little concern for civilian casualties.
  4. Rather than trying to minimize the damage and deaths in the country under attack, some untypical members of the military may attempt with relish to maximize such damage and deaths.
  5. In some cases, members of the US military may act to prolong or escalate a war, for doubtful reasons such as vengeance, achieving a more resounding victory, terrifying the enemy into subjugation, proving the prowess of particular weapon systems, or justifying the sacrifice of those already dead.
  6. Some untypical officers in the military may recommend particular attacks for dubious reasons such as winning medals, getting promotions, demonstrating their executive prowess, or testing their pet theories.

There is a great contrast between these two viewpoints. Just as it possible to view the activity of the US president and the military in two very different ways (one idealized and another more realistic), it is possible to view the activities of scientists in two different ways: one viewpoint that is very idealized and another viewpoint that is much more realistic. It is much more common for people to be exposed to the idealized, rose-colored viewpoint about scientific activity. Below are some of the ideas of this viewpoint:

  1. Scientists are people who judge truth in the same disinterested and dispassionate way that judges or jurors consider court cases.
  2. A scientist's statements on a scientific question are always dictated entirely by the relevant facts, and such statements are not heavily influenced by the scientist's ideology or by selfish considerations having to do with the scientist's economic interests or career prospects.
  3. Scientists are very careful about only making statements that are warranted by facts and observations.
  4. When a theory gains popularity among scientists, it is always because a great mass of evidence has accumulated showing that such a theory is very probably true.
  5. Unlike people in religion, scientists do not believe on the basis of authority.

The viewpoint above is a kind of an idealized rose-colored viewpoint that puts scientists on a pedestal, and attributes to them a kind of intellectual virtue that few humans have. There is a more realistic viewpoint you can have about scientists and scientific activity. Below are some of the ideas of that viewpoint:

  1. While most of the assertions of scientists are well supported by observations or evidence, it is also very common for scientists to assert claims that are not well supported by observations and evidence, particularly speculative theories that have gradually spread among scientist communities through a kind of bandwagon effect, a social contagion effect.
  2. Scientists often describe as “science” or “scientific” doubtful claims that are not actually science in the strictest sense, because they have not been well established by observations or experiments.
  3. Because there are very strong financial and professional penalties for being a “renegade” scientist who disagrees with the majority on some topic, scientists are under strong peer-pressure to conform to community norms of belief, even when such norms are unwarranted.
  4. Conformism and yielding to authority are very strong factors influencing scientific assertions, with scientists being under great pressure to conform to the opinions of revered scientific authority figures, living and dead.
  5. There is great overconfidence and hubris among many scientists, who often claim to understand things they don't understand, partially because such assertions enhance their prestige or the prestige of their group, making it appear they have a topic mastery that is not actually possessed.
  6. There are many problems in current science practice, including excessive jargon and obfuscation, research results that very often are never reproduced, and excessive hype of marginal results.

To do intelligent science journalism, a writer should at least occasionally take a viewpoint like the second of these viewpoints. Such a viewpoint involves some of the sociological insight that is needed for realistic analysis. But such a critical perspective is very rarely taken by our mainstream science writers, who seem to almost always be taking “looking up from under the pedestal” viewpoints toward the modern scientist. These pom-pom writers seem to act more like cheerleaders than journalists.

Let us imagine a country in which the press reported uncritically the assertions of the government. In this country, each time the leader of a country stated something, it would be reported as gospel truth by the press. In this country when some group of government officials such as a Senate committee came to a decision, the journalists would report that decision as if it were something that could scarcely be doubted. And whenever a president wanted to start a war, the press would publish the White House spin without criticism. Now clearly in such a country the press would not be doing its proper job. The proper job of the press is to not to just report what authorities in power are saying, but to subject such claims to critical scrutiny.

Thankfully we do not live in a country with a press that is a lap-dog to authorities in government. But we do live in a country where the press is pretty much a lap-dog to authorities in academia. Our science writers typically treat the pronouncements of professors with kind of the same  reverence that North Korean journalists treat the utterances of government officials. 

Mainstream science writers seem to think that their mission consists of the following:

  1. To get the public interested in science papers that are written in prose that is typically rather boring.
  2. To get people to understand scientific progress that may be written up in some jargon-filled prose that is hard for the layman to understand.

But there are additional important roles that science writers should be undertaking:

  1. To subject the claims of science authorities to critical scrutiny, which may involve sometimes pointing out that the evidence does not back up the claim being made.
  2. To point out inconsistencies, weaknesses, implausibilities or unwarranted assertions in the claims of science authorities, whenever such things occur.

But these two roles are hardly being performed by mainstream science writers, who seem to typically act like cheerleaders, like people no more prone to challenge the pronouncements of authorities than journalists in China or North Korea. 

Let us look at an example of how pom-pom science journalists failed to do their job. A scientific paper was published claiming to have produced evidence for memory traces in the hippocampus. Some mice were trained to fear an electric shock delivered in a particular spot. Then some fancy gizmo was hooked up to their brains, which supposedly delivered a kind of energy burst in some particular area of the brain where the scientists thought the memories were stored. The "fear freezing" behavior of the mice was reported as being different when such a burst was delivered, and the scientists reported this as evidence that parts of the hippocampus contain "contain memory traces for fear-inducing contexts." 

Our pom-pom science journalists reported such a result uncritically. But adequate coverage of this paper would have put such a paper in a proper light by discussing all of the following things:

  • The results were produced testing a number of mice, but the paper doesn't tell us how many mice were tested. If only a few mice were tested, we should have very little confidence in the results.
  • A mouse receiving a burst of energy may freeze not because some previous fear-training memory was activated by the energy, but because the mouse is responding to a novel, unexpected stimulus.
  • The paper was based on judgments of fear-freezing in mice, which is a very subjective thing to judge, the type of thing where an experimenter bias could easily have crept in.
  • The paper was experimenting with mice, but no such results have been produced with humans; so the result may not reveal anything about human memory.  
  • The result suggested by the experiment contradicts the result produced over many years of experiments by Karl Lashley, who did all kinds of experiments testing memories in animals after removing or damaging parts of their brains, and could find no evidence that any particular memory was stored in any particular part of the brain.
  • The leading journal Nature published an article entitled “Brain-manipulation studies may produce spurious links to behavior,” pointing out that shooting energy into one part of a brain (the technique used by the paper) may cause other parts of the brain to fire off, resulting in unpredictable effects.
  • The graphs of the scientific paper show only very small differences between the behavior of the mice that received the burst of energy and those that did not. After 10 or 20 tries, any experimenter could have probably produced such marginal results testing with a meaningless stimulus such as saying the word “Abracadabra,” because of mere chance variations.

Thursday, January 11, 2018

He Tries to Pump Some "Star Wars" Glamour into Panpsychism

In his post “Why Panpsychism is the Jedi Philosophy,” BigThink.com columnist Scott Hendricks starts out by describing the Force, the mysterious cosmic energy source depicted in the Star Wars movies. Here is how Obi-Wan Kenobi first describes the Force in the first Star Wars movie:

The Force is what gives a Jedi his power. It's an energy field created by all living things. It surrounds us and penetrates us; it binds the galaxy together.

Yoda the Jedi master of the Force explains it this way: “Life creates it, makes it grow. Its energy surrounds us and binds us."

After describing the Star Wars depiction of the force, Hendricks says, “There is a name for this philosophy in real life, panpsychism.” But Hendricks errs. The depiction of the Force in the Star Wars movies is not any statement of the philosophy of panpsychism.

Panpsychism is the idea that all matter is to some degree conscious. But the Star Wars idea of the Force is not an idea about matter.  It is an idea about a cosmic energy. No one in the Star Wars movies ever makes the panpsychist claim that all matter is conscious, nor does any such character claim that any nonliving material thing is conscious.

Hendricks incorrectly describes how the Force is depicted in the Star Wars movies. He tells us, “While only some things, notably Force-sensitive characters, can manipulate the Force, every object in the universe appears to be able to interact with the Force.” He provides a link to try to back up this claim, which merely takes us to the first description of the Force in the Star Wars movies:

The Force is what gives a Jedi his power. It's an energy field created by all living things. It surrounds us and penetrates us; it binds the galaxy together.

But that quote does not at all back up the claim that “every object in the universe appears to be able to interact with the Force,” an idea never presented in the Star Wars movies. To the contrary, the two quotes above (by Obi-Wan Kenobi and Yoda) tell us that the force is created specifically by living things, not by material things in general. 

Poster of the latest Star Wars movie

In the Star Wars movies, the Force is associated with psychic powers such as telepathy and psychokinesis. The masters of the Force known as Jedi can influence the minds of others through thought suggestion, as Obi-Wan Kenobi does when he gets out of a jam by telepathically influencing the mind of a security guard. A Jedi can also sense distant important events by sensing a disturbance in the Force, as Obi-Wan does when he detects a “great disturbance in the Force” when the Death Star destroys a distant planet. A Jedi can even use the force to move objects such as a light saber. Someone can also use the Force to achieve things he could never normally do, such as when Luke Skywalker uses the Force to help him perform the difficult task of blowing up the Death Star.

None of this has anything to do with panpsychism, and panpsychism is not associated with any claims or beliefs about psychic powers. Panpsychism has never been associated with any types of claims about a cosmic force, mysterious or non-mysterious.

From the table below we can see there is basically nothing that panpsychism has in common with the Star Wars concept of the Force.

Panpsychism Star Wars concept of the Force
Make a claim about matter? Yes No
Claims all matter is conscious? Yes No
Makes a claim about a cosmic energy field? No Yes
Makes a claim about psychic powers (telepathy, psychokinesis)? No Yes
Differentiates between living and non-living things? No Yes (the Force is described as a product of all living things, not all matter)
Suggests some cosmic will? No Yes (“will of the Force” in episode 1)
Associated with post-mortal survival? No Maybe (ghost of Obi-Wan Kenobi twice seen)

Although the Star Wars movies tell us nothing about how the Force might relate to life-after-death, the movies hint that there may be such a relation. In Episode 4 we hear the voice of the deceased Obi-Wan Kenobi telling Luke Skywalker to “use the force.” In Episode 5 we see the ghost of Obi-Wan Kenobi appearing to Luke Skywalker. In Episode 6 we the ghost of Obi-Wan Kenobi, Darth Vader and Yoda all appearing to Luke Skywalker. Since these were all great masters of the Force, we can infer some relation between the Force and their post-mortal survival.

Hendrick's attempt to glamorize panpsychism by calling it “the Jedi philosphy” is erroneous. If we want to find philosophical ideas that partially mirror the metaphysics of Star Wars, the two below are much better matches:

Vitalism: Vitalism is the idea that there is some mysterious life force involved with all living things. This sounds a little like the claim twice made in the Star Wars movies that the Force is created by all living things.
Spiritualism: Spiritualism is the idea that people survive death, and can communicate with the living. When the deceased Obi-Wan Kenobi communicates to Luke Skywalker in Episode 4 and Episode 5 of the Star Wars series, this is very much a fictional expression of the idea of spiritualism. 

Panpsychism is largely an attempt to help deal with the problem that there is no apparent reason why the neurons in a brain could ever generate a mind such as humans have.  The panpsychist kind of tells us that such a thing is not so unthinkable, because every little neuron (and every other little thing) is a tiny bit conscious. The problem is that similar reasoning would lead us to believe that the boulders at the seashore or the trees in the forest have bigger minds than we have, since they have even more material particles than are in our brains.  A better way to deal with the "How could minds arise from brains?" problem is to simply conclude: they don't.  The claim that minds arise from brains has been asserted countless times, but never proven.  There are good reasons for doubting such a claim, as you will sometimes read about on this blog.