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The Diet That Might Cure Depression

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From March 2018, Olga Khazan writes in the Atlantic:

At the turn of the 20th century, prominent physicians who were trying to understand where mental illness comes from seized on a new theory: autointoxication. Intestinal microbes, these doctors suggested, are actually dangerous to their human hosts. They have a way of inducing “fatigue, melancholia, and the neuroses,” as a historical article in the journal Gut Pathogens recounts.

“The control of man’s diet is readily accomplished, but mastery over his intestinal bacterial flora is not,” wrote a doctor named Bond Stow in the Medical Record Journal of Medicine and Surgery in 1914. “The innumerable examples of autointoxication that one sees in his daily walks in life is proof thereof … malaise, total lack of ambition so that every effort in life is a burden, mental depression often bordering upon melancholia.”

Stow went on to say that “a battle royal must be fought” with these intestinal germs.

Another physician, Daniel R. Brower of Rush Medical College, suspected that the increasing rates of melancholia—depression—in Western society might be the result of changing dietary habits and the resulting toxins dwelling in the gut.

Of course, like most medical ideas at the time, this one was not quite right. (And the proposed cures—removing part of the colon or eating rotten meat—seem worse than the disease.) Your gut doesn’t contain “toxins” that are poisonous so much as it hosts a diverse colony of bacteria called the “microbiome.” But these doctors were right about one thing: What we eat does affect how we feel, and gut microbes likely play a role.

A poor diet is a leading risk factor for early death, responsible for one in five deaths globally. Depression, meanwhile, is the leading cause of disability worldwide. A relatively new line of research suggests the two might be related: An unhealthy diet might make us depressed, and depression, in turn, makes us feel even sicker.

In a recently released abstract, researchers studying 964 elderly participants over six and a half years found those who followed the dash diet, which emphasizes whole grains, fruits, and vegetables, had lower rates of depression, while those who ate a traditional Western diet were more prone to depression. The participants were asked how often they ate various foods, and they were screened for depression annually using a questionnaire.

“I think we need to view food as medicine,” Laurel J. Cherian, an assistant professor of vascular neurology at Rush University Medical Center in Chicago and the study’s lead author, told me. “Medications to treat depression are wonderful, but for many people, it’s going to be a combination of things.”

The research will be presented at the upcoming meeting of the American Academy of Neurology. The study has not been published yet in a peer-reviewed journal, but other researchers have found similar antidepression benefits from the dash diet, which was developed by the U.S. National Heart, Lung, and Blood Institute.

Past research has found that following the DASH diet was associated with reduced depression in adolescent girls and with less physician-diagnosed depression among thousands of Spaniards. The results in teens suggest that diet could be a way to stave off some mental disorders entirely, since half of all mental illnesses start in the teen years.

John Cryan, an expert in the gut-brain connection at University College Cork in Ireland, said he’s enthusiastic about this field, but there are a few cautionary notes about this study in particular. It’s an observational study, for example, and it studied a very old population. “Geriatric depression is a different beast,” he says.

Of course, rich people tend to be happier and can afford to eat better. Cherian’s study did not control for socioeconomic status. But overall, the evidence suggests diet improves depression symptoms even when controlling for factors like income or education, says Felice Jacka, a professor of nutritional psychiatry at Australia’s Deakin University.

Jacka found in 2010 that women who ate a diet high in produce, meat, fish, and whole grains had lower odds of major depression and anxiety than others. Since then, a meta-analysis of 21 studies found that “a dietary pattern characterized by high intakes of fruit, vegetables, whole grain, fish, olive oil, low-fat dairy and antioxidants and low intakes of animal foods was apparently associated with a decreased risk of depression.”

In fact, Jacka told me that at this point, the connection between diet and depression is so well-established that more studies like Cherian’s aren’t really necessary. “Given how many observational studies there are already published, the field does not really need more of these,” she said. “What it needs now are interventions that show that if you improve diet, you also improve depression.” Jacka found in a small study last year that depressed people were more likely to see improvements in their mood if they were given dietary advice over a three-month period, rather than just social support. She says such interventions are cost-effective, to boot. . .

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Written by LeisureGuy

12 November 2019 at 10:42 am

How the gut microbiome affects the brain and mind

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Written by LeisureGuy

10 November 2019 at 7:07 am

How to Increase Gut Bacterial Richness

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Dr. Michael Greger blogs:

We live in an “obesogenic environment,” with cheap junk food everywhere, thanks in part to subsidies going to the “‘food industrial complex,’ which manufactures obesogenic foods that foster addiction…The root causes…[may] make obesity difficult to escape,” but a lot of people do. If it were simply the external environment, why isn’t everyone obese?

“Some individuals seem to be more susceptible to the obesogenic environment…than others,” which suggests a genetic component, supported by studies of twins and adopted kids, but the genes that have been identified so far account for only 6 to 11 percent of the genetic variation in body mass index between individuals. Perhaps variation in our “other genome”—that is, all the different microbes that inhabit our body, known as the microbiome—may be playing a role. We have a hundred times more bacterial genes inside us than human genes.

As I discuss in my video Gut Microbiome: Strike It Rich with Whole Grains, a study found that people tend to fall into one of two groups: those who have lots of different types of bacteria in their gut (high “gut bacterial richness”) and those with relatively few types. Those with low bacterial richness had more overall body fat, insulin resistance, which is the cause of type 2 diabetes, high triglycerides, and higher levels of inflammatory markers, like C-reactive protein, compared to those with high bacterial richness. Not only did people with lower bacterial richness start out heavier, but the obese individuals with lower bacterial richness also gained more weight over time.

The question then becomes: Can a dietary intervention have any impact “A number of studies have associated increased microbial richness…with diets higher in fruits, vegetables, and fiber.”

Just giving fiber-type supplements doesn’t seem to boost richness, however, but the “compositional complexity” of a whole food, like whole grains, “could potentially support a wider scope of bacterial taxa,” types of bacteria, “thereby leading to an increase in diversity.” Human studies to investigate the effects of whole grains had been neglected, though…until now.

Subjects were given whole-grain barley, brown rice, or a mixture of both for a month, and all three caused an increase in bacterial community diversity. Therefore, it may take a broad range of substrates to increase bacterial diversity, and this can be achieved by eating whole plant foods.

Moreover, the alterations of gut bacteria in the study coincided with a drop in systemic inflammation in the body. We used to think that the way fiber in whole grains helped us was by gelling in our small intestine right off of our stomach, slowing the rate at which sugars were absorbed and blunting the spike in blood sugars one might get from refined carbs. We now know, however, that fiber is broken down in our colon by our friendly flora, which release all sorts of beneficial substances into our bloodstream that can have anti-inflammatory effects, as well. So, perhaps what’s happening in our large intestine helps explain the protective effects of whole grain foods against type 2 diabetes.

Interestingly, the combination of both barley and brown rice worked better than either grain alone, suggesting a synergistic effect. This may help explain “the discrepancy of the health effects of whole grains obtained in epidemiological [population-based] and interventional studies.”

Observational studies “strongly suggest” that those who consume three or more servings of whole grains a day tend to have a lower body mass index, less belly fat, and less tendency to gain weight, but recent clinical trials, where researchers randomized subjects to eat white bread rolls versus whole-wheat rolls, failed to provide evidence of a beneficial effect on body weight. Of course, whole grains are so superior nutritionally that they should continue to be encouraged. However, the “[i]nterventional trials might have failed to show [weight] benefits because they focused on a limited selection of whole grains, while in epidemiological trials [or the population studies], subjects are likely to consume a diverse set of whole grains which might have synergistic activities.”


Until recently, we knew very little about how powerfully our gut bacteria can affect our health. Catch up on the latest science with these related videos: . . .

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Written by LeisureGuy

10 November 2019 at 6:26 am

The smart move: we learn more by trusting than by not trusting

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Hugo Mercier, a research scientist at the CNRS (Institut Jean Nicod) in Paris where he works with the Evolution and Social Cognition team, writes in Aeon:

We all know people who have suffered by trusting too much: scammed customers, jilted lovers, shunned friends. Indeed, most of us have been burned by misplaced trust. These personal and vicarious experiences lead us to believe that people are too trusting, often verging on gullibility.

In fact, we don’t trust enough.

Take data about trust in the United States (the same would be true in most wealthy democratic countries at least). Interpersonal trust, a measure of whether people think others are in general trustworthy, is at its lowest in nearly 50 years. Yet it is unlikely that people are any less trustworthy than before: the massive drop in crime over the past decades suggests the opposite. Trust in the media is also at bottom levels, even though mainstream media outlets have an impressive (if not unblemished) record of accuracy.

Meanwhile, trust in science has held up comparatively well, with most people trusting scientists most of the time; still, in some areas at least, from climate change to vaccination, a share of the population doesn’t trust science enough – with devastating consequences.

Social scientists have a variety of tools to study how trusting, and how trustworthy, people are. The most popular is the trust game, in which two participants play, usually anonymously. The first participant is given a small amount of money, $10 say, and asked to decide how much to transfer to the other participant. The amount transferred is then tripled, and the second participant chooses how much to give back to the first. In Western countries at least, trust is rewarded: the more money the first participant transfers, the more money the second participant sends back, and thus the more money the first participant ends up with. In spite of this, first participants on average transfer only half the money they have received. In some studies, a variant was introduced whereby participants knew each other’s ethnicity. Prejudice led participants to mistrust certain groups – Israeli men of Eastern origin (Asian and African immigrants and their Israeli-born offspring), or black students in South Africa – transferring them less money, even though these groups proved just as trustworthy as more esteemed groups.

If people and institutions are more trustworthy than we give them credit for, why don’t we get it right? Why don’t we trust more?

In 2017, the social scientist Toshio Yamagishi was kind enough to invite me to his flat in Machida, a city in the Tokyo metropolitan area. The cancer that would take his life a few months later had weakened him, yet he retained a youthful enthusiasm for research, and a sharp mind. On this occasion, we discussed an idea of his with deep consequences for the question at hand: the informational asymmetry between trusting and not trusting.

When you trust someone, you end up figuring out whether your trust was justified or not. An acquaintance asks if he can crash at your place for a few days. If you accept, you will find out whether or not he’s a good guest. A colleague advises you to adopt a new software application. If you follow her advice, you will find out whether the new software works better than the one you were used to.

By contrast, when you don’t trust someone, more often than not you never find out whether you should have trusted them. If you don’t invite your acquaintance over, you won’t know whether he would have made a good guest or not. If you don’t follow your colleague’s advice, you won’t know if the new software application is in fact superior, and thus whether your colleague gives good advice in this domain.

This informational asymmetry means that we learn more by trusting than by not trusting. Moreover, when we trust, we learn not only about specific individuals, we learn more generally about the type of situations in which we should or shouldn’t trust. We get better at trusting.

Yamagishi and his colleagues demonstrated the learning advantages of being trusting. Their experiments were similar to trust games, but the participants could interact with each other before making the decision to transfer money (or not) to the other. The most trusting participants were better at figuring out who would be trustworthy, or to whom they should transfer money.

We find the same pattern in other domains. People who trust the media more are more knowledgeable about politics and the news. The more people trust science, the more scientifically literate they are. Even if this evidence remains correlational, it makes sense that people who trust more should get better at figuring out whom to trust. In trust as in everything else, practice makes perfect.

Yamagishi’s insight provides us with a reason to be trusting. But then, the puzzle only deepens: if trusting provides such learning opportunities, we should trust too much, rather than not enough. Ironically, the very reason why we should trust more – the fact that we gain more information from trusting than from not trusting – might make us inclined to trust less.

When our trust is disappointed – when we trust someone we shouldn’t have – the costs are salient, and our reaction ranges . . .

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Written by LeisureGuy

9 November 2019 at 2:09 pm

Scientist Who Discredited Meat Guidelines Didn’t Report Past Food Industry Ties

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Tara Parker-Pope and 

surprising new study challenged decades of nutrition advice and gave consumers the green light to eat more red and processed meat. But what the study didn’t say is that its lead author has past research ties to the meat and food industry.

The new report, published this week in the Annals of Internal Medicine, stunned scientists and public health officials because it contradicted longstanding nutrition guidelines about limiting consumption of red and processed meats. The analysis, led by Bradley C. Johnston, an epidemiologist at Dalhousie University in Canada, and more than a dozen researchers concluded that warnings linking meat consumption to heart disease and cancer are not backed by strong scientific evidence.

Several prominent nutrition scientists and health organizations criticized the study’s methods and findings. But Dr. Johnston and his colleagues defended the work, saying it relied on the highest standards of scientific evidence, and noted that the large team of investigators reported no conflicts of interest and conducted the review without outside funding.

Dr. Johnston also indicated on a disclosure form that he did not have any conflicts of interest to report during the past three years. But as recently as December 2016 he was the senior author on a similar study that tried to discredit international health guidelines advising people to eat less sugar. That study, which also appeared in the Annals of Internal Medicine, was paid for by the International Life Sciences Institute, or ILSI, an industry trade group largely supported by agribusiness, food and pharmaceutical companies and whose members have included McDonald’s, Coca-Cola, PepsiCo and Cargill, one of the largest beef processors in North America. The industry group, founded by a top Coca-Cola executive four decades ago, has long been accused by the World Health Organization and others of trying to undermine public health recommendations to advance the interests of its corporate members.

In an interview, Dr. Johnston said his past relationship with ILSI had no influence on the current research on meat recommendations. He said he did not report his past relationship with ILSI because the disclosure form asked only about potential conflicts within the past three years. Although the ILSI-funded study publication falls within the three-year window, he said the money from ILSI arrived in 2015, and he was not required to report it for the meat study disclosure.

“That money was from 2015 so it was outside of the three year period for disclosing competing interests,” said Dr. Johnston. “I have no relationship with them whatsoever.”

Critics of the meat study say that while Dr. Johnston may have technically complied with the letter of the disclosure rules, he did not comply with the spirit of financial disclosure.

“Journals require disclosure, and it is always better to disclose fully, if for no other reason than to stay out of trouble when the undisclosed conflicts are exposed,” said Marion Nestle, a professor of nutrition, food studies and public health at New York University who studies conflicts of interest in nutrition research. “Behind the scenes, ILSI works diligently on behalf of the food industry; it is a classic front group. Even if ILSI had nothing to do with the meat papers — and there is no evidence of which I am aware that it did — the previous paper suggests that Johnston is making a career of tearing down conventional nutrition wisdom.”

Notably, Dr. Johnston and colleagues thought it was important to fully disclose their personal eating habits. The meat paper includes an appendix titled “Summary of Panelists’ Potential Conflicts of Interest,” that discloses whether each author eats red or processed meat and how often. Johnston reported no financial conflicts of interest but disclosed that he eats one to two servings of red or processed meat per week.

“We think that’s a potential bias that is worth disclosing,” said Dr. Johnston about the researchers’ personal eating habits.

Dr. Johnston’s ties to the 2016 ILSI-funded sugar study show how ILSI has methodically cultivated allies in academia around the world, and how it recruits influential scientists to help shape global nutrition advice and counter what it perceives to be anti-food industry guidelines by health organizations.

When Dr. Johnston and his colleagues first published the sugar study, they said that ILSI had no direct role in conducting the research other than providing funding, but later amended their disclosure statement in the Annals after The Associated Press obtained emails showing that ILSI had “reviewed” and “approved” the study’s protocol.

Dr. Johnston said that when he published the sugar study in 2016, he put his connection with the food industry group “front and center.” He said in hindsight he was “naïve” when he agreed to work on the ILSI-funded study about sugar guidelines. It was during a conference call on the sugar study that he realized the extent that industry figures were involved with that organization. He declined to say who was on the conference call. . . .

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Written by LeisureGuy

9 November 2019 at 2:03 pm

What’s Your Gut Microbiome Enterotype?

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Yet another reason to favor a plant-based diet: it tilts your gut microbiome in your favor (and away from colon cancer).

Written by LeisureGuy

8 November 2019 at 5:57 pm

Minding matter: Physics vs. reality

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Adam Frank, professor of astrophysics at the University of Rochester in New York, writes in Aeon:

Materialism holds the high ground these days in debates over that most ultimate of scientific questions: the nature of consciousness. When tackling the problem of mind and brain, many prominent researchers advocate for a universe fully reducible to matter. ‘Of course you are nothing but the activity of your neurons,’ they proclaim. That position seems reasonable and sober in light of neuroscience’s advances, with brilliant images of brains lighting up like Christmas trees while test subjects eat apples, watch movies or dream. And aren’t all the underlying physical laws already known?

From this seemly hard-nosed vantage, the problem of consciousness seems to be just one of wiring, as the American physicist Michio Kaku argued in The Future of the Mind (2014). In the very public version of the debate over consciousness, those who advocate that understanding the mind might require something other than a ‘nothing but matter’ position are often painted as victims of wishful thinking, imprecise reasoning or, worst of all, an adherence to a mystical ‘woo’.

It’s hard not to feel the intuitional weight of today’s metaphysical sobriety. Like Pickett’s Charge up the hill at Gettysburg, who wants to argue with the superior position of those armed with ever more precise fMRIs, EEGs and the other material artefacts of the materialist position? There is, however, a significant weakness hiding in the imposing-looking materialist redoubt. It is as simple as it is undeniable: after more than a century of profound explorations into the subatomic world, our best theory for how matter behaves still tells us very little about what matter is. Materialists appeal to physics to explain the mind, but in modern physics the particles that make up a brain remain, in many ways, as mysterious as consciousness itself.

When I was a young physics student I once asked a professor: ‘What’s an electron?’ His answer stunned me. ‘An electron,’ he said, ‘is that to which we attribute the properties of the electron.’ That vague, circular response was a long way from the dream that drove me into physics, a dream of theories that perfectly described reality. Like almost every student over the past 100 years, I was shocked by quantum mechanics, the physics of the micro-world. In place of a clear vision of little bits of matter that explain all the big things around us, quantum physics gives us a powerful yet seemly paradoxical calculus. With its emphasis on probability waves, essential uncertainties and experimenters disturbing the reality they seek to measure, quantum mechanics made imagining the stuff of the world as classical bits of matter (or miniature billiard balls) all but impossible.

Like most physicists, I learned how to ignore the weirdness of quantum physics. ‘Shut up and calculate!’ (the dictum of the American physicist David Mermin) works fine if you are trying to get 100 per cent on your Advanced Quantum Theory homework or building a laser. But behind quantum mechanics’ unequaled calculational precision lie profound, stubbornly persistent questions about what those quantum rules imply about the nature of reality – including our place in it.

Those questions are well-known in the physics community, but perhaps our habit of shutting up has been a little too successful. A century of agnosticism about the true nature of matter hasn’t found its way deeply enough into other fields, where materialism still appears to be the most sensible way of dealing with the world and, most of all, with the mind. Some neuroscientists think that they’re being precise and grounded by holding tightly to materialist credentials. Molecular biologists, geneticists, and many other types of researchers – as well as the nonscientist public – have been similarly drawn to materialism’s seeming finality. But this conviction is out of step with what we physicists know about the material world – or rather, what we don’t know.

Albert Einstein and Max Planck introduced the idea of the quantum at the beginning of the 20th century, sweeping away the old classical view of reality. We have never managed to come up with a definitive new reality to take its place. The interpretation of quantum physics remains as up for grabs as ever. As a mathematical description of solar cells and digital circuits, quantum mechanics works just fine. But if one wants to apply the materialist position to a concept as subtle and profound as consciousness, something more must clearly be asked for. The closer you look, the more it appears that the materialist (or ‘physicalist’) position is not the safe harbor of metaphysical sobriety that many desire.

For physicists, the ambiguity over matter boils down to what we call the measurement problem, and its relationship to an entity known as the wave function. Back in the good old days of Newtonian physics, the behaviour of particles was determined by a straightforward mathematical law that reads F = ma. You applied a force F to a particle of mass m, and the particle moved with acceleration a. It was easy to picture this in your head. Particle? Check. Force? Check. Acceleration? Yup. Off you go.

The equation F = ma gave you two things that matter most to the Newtonian picture of the world: a particle’s location and its velocity. This is what physicists call a particle’s state. Newton’s laws gave you the particle’s state for any time and to any precision you need. If the state of every particle is described by such a simple equation, and if large systems are just big combinations of particles, then the whole world should behave in a fully predictable way. Many materialists still carry the baggage of that old classical picture. It’s why physics is still widely regarded as the ultimate source of answers to questions about the world, both outside and inside our heads.

In Isaac Newton’s physics, position and velocity were indeed clearly defined and clearly imagined properties of a particle. Measurements of the particle’s state changed nothing in principle. The equation F = ma was true whether you were looking at the particle or not. All of that fell apart as scientists began probing at the scale of atoms early last century. In a burst of creativity, physicists devised a new set of rules known as quantum mechanics. A critical piece of the new physics was embodied in Schrödinger’s equation. Like Newton’s F = ma, the Schrödinger equation represents mathematical machinery for doing physics; it describes how the state of a particle is changing. But to account for all the new phenomena physicists were finding (ones Newton knew nothing about), the Austrian physicist Erwin Schrödinger had to formulate a very different kind of equation.

When calculations are done with the Schrödinger equation, what’s left is not the Newtonian state of exact position and velocity. Instead, you get what is called the wave function (physicists refer to it as psi after the Greek symbol Ψ used to denote it). Unlike the Newtonian state, which can be clearly imagined in a commonsense way, the wave function is an epistemological and ontological mess. The wave function does not give you a specific measurement of location and velocity for a particle; it gives you only probabilities at the root level of reality. Psi appears to tell you that, at any moment, the particle has many positions and many velocities. In effect, the bits of matter from Newtonian physics are smeared out into sets of potentials or possibilities.

It’s not just position and velocity that get smeared out. The wave function treats all properties of the particle (electric charge, energy, spin, etc) the same way. They all become probabilities holding many possible values at the same time. Taken at face value, it’s as if the particle doesn’t have definite properties at all. This is what the German physicist Werner Heisenberg, one of the founders of quantum mechanics, meant when he advised people not to think of atoms as ‘things’. Even at this basic level, the quantum perspective adds a lot of blur to any materialist convictions of what the world is built from.

Then things get weirder still. According to the standard way of treating the quantum calculus, the act of making a measurement on the particle kills off all pieces of the wave function, except the one your instruments register. The wave function is said to collapse as all the smeared-out, potential positions or velocities vanish in the act of measurement. It’s like the Schrödinger equation, which does such a great job of describing the smeared-out particle before the measurement is made, suddenly gets a pink slip.

You can see how this throws a monkey wrench into a simple, physics-based view of an objective materialist world. How can there be one mathematical rule for the external objective world before a measurement is made, and another that jumps in after the measurement occurs? For a hundred years now, physicists and philosophers have been beating the crap out of each other (and themselves) trying to figure out how to interpret the wave function and its associated measurement problem. What exactly is quantum mechanics telling us about the world? What does the wave function describe? What really happens when a measurement occurs? Above all, what is matter?

There are today no definitive answers to these questions. There is not even a consensus about what the answers should look like. Rather, there are multiple interpretations of quantum theory, each of which corresponds to a very different way of regarding matter and everything made of it – which, of course, means everything. The earliest interpretation to gain force, the Copenhagen interpretation, is associated with Danish physicist Niels Bohr and other founders of quantum theory. In their view, it was meaningless to speak of the properties of atoms in-and-of-themselves. Quantum mechanics was a theory that spoke only to our knowledge of the world. The measurement problem associated with the Schrödinger equation highlighted this barrier between epistemology and ontology by making explicit the role of the observer (that is: us) in gaining knowledge.

Not all researchers were so willing to give up on the ideal of objective access to a perfectly objective world, however. Some pinned their hopes on the discovery of hidden variables – a set of deterministic rules lurking beneath the probabilities of quantum mechanics. Others took a more extreme view. In the many-worlds interpretation espoused by the American physicist Hugh Everett, the authority of the wave function and its governing Schrödinger equation was taken as absolute. Measurements didn’t suspend the equation or collapse the wave function, they merely made the Universe split off into many (perhaps infinite) parallel versions of itself. Thus, for every experimentalist who measures an electron over here, a parallel universe is created in which her parallel copy finds the electron over there. The many-worlds Interpretation is one that many materialists favor, but it comes with a steep price.

Here is an even more important point: as yet . . .

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Written by LeisureGuy

8 November 2019 at 4:43 pm

Posted in Daily life, Science

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