from the world's big
Nobody Really Understands Quantum Mechanics
Tim Maudlin is a professor of philosophy at Rutgers University. He is the author of "Quantum Non-Locality and Relativity," "Truth and Paradox," and "The Metaphysics within Physics," as well as many articles on the foundations of physics, logic, and the philosophy of science. His main areas of study pertain to the ways that physics intersects with philosophy.
Question: How can philosophers help us to understand quantum mechanics?
Tim Maudlin: How should anybody think about quantum mechanics? Quantum mechanics is a perfect example. So you have Richard Fineman famously saying he can safely say nobody understands quantum mechanics. Right? One of the greatest physicists of the 20th century who’s main work was in quantum mechanics claiming he didn’t understand it. He says he himself does not really understand the picture of the world that quantum mechanics is presenting us with. I would think a physicist, as I say, as a physicist should find that frustrating and upsetting and a failure of physics that this fundamental mathematical theory they’re using they find they don’t really even have in themselves the sense they understand what it’s telling you about the world.
It’s just that if you’re a philosopher, you have the luxury of spending all of your time with that worry of beating your head against it. As a matter of fact, it’s a hard question and it requires people thinking very carefully and very deeply and furthermore, coming up with detailed physical theories, detailed physical accounts to try to understand quantum mechanics. And that foundational work tends not to have immediate payoff practically. It doesn’t mean that the predictions of the theory when you make sense of quantum mechanics will change or will change much. Sometimes they even change a little. Sometimes people trying to understand quantum mechanics will propose a way of understanding it that actually means the very predictions it makes will be altered a tiny bit, often such a tiny bit that you can’t even check it in the lab.
But there’s not that much practical payoff, and insofar as you are a physicist who care about practical payoff or you’re embedded in a larger enterprise that cares about practical payoff, then you’re going to regard these questions as not of immediate interest. Right? They’re not going to repay you thinking about them. And the luxury that philosophers have is that as we’re paid to think about things that don’t pay to think about. And so we can spend our time worried about these foundational issues and not feeling guilty about them.
Question: What is the payoff that you get from this kind of inquiry?
Tim Maudlin: Well there are two things you would like to do. Ultimately you would like to settle on a clear physical account of the world. Like, what’s going on, like I say, go back to my electron. What’s really going on with that electron? The aim you have is to answer that question. Now as it turns out, if you look at the precisely defined interpretations of quantum mechanics that exist today; and by precisely defined, I mean the ones where you have a clear mathematical account of what’s going on, in terms that are not vague and ambiguous. For example, if someone in the standard theory you say, “Oh, a system will develop in a certain way until you measure something on it. And when you measure something, then things go very differently.” And as John Bell pointed out, that’s just unacceptable vagueness because, what does it mean to measure something? You know, you’re saying in on circumstance it does one thing in another circumstance it does another very different thing, but the difference between those two circumstances it not well defined.
So the first ting you want to do is have a clear theory. A theory that tells you clearly what exists, tells you clearly what it does, and that you see, well given that, I can understand the world around me. As it turns out, there are various ways to do this; quite different ways to do it. Ways that give you very, very different pictures of what’s going on in the world in a microscopic scale.
What you’d like to then do is choose among them. Now, you may not be able to do it. How do you choose among them? Ultimately you’d like to do it empirically. You’d like to say, well there’s some experiment I’d like to run to decide between these. But in certain cases, it’s sort of provable that no experiment can decide between them. Or you might hope that one of these pictures and not another, one of these models and not another can be extended to cover gravity or can be extended to cover some new phenomenon. And then that would give you a reason to prefer one.
It may turn out that at the end of the day, we will never know. It may turn out that the world has not been made and our brains have not been made and our access to the world through our senses has not been made to allow us to discover all of the facts about it. And then you’d be depressed a little bit. Those are the breaks, right.
Recorded September 17, 2010
Interviewed by David Hirschman
Physicists should find it frustrating and upsetting that they don't really get what this fundamental mathematical theory tells us about the world.
If machines develop consciousness, or if we manage to give it to them, the human-robot dynamic will forever be different.
- Does AI—and, more specifically, conscious AI—deserve moral rights? In this thought exploration, evolutionary biologist Richard Dawkins, ethics and tech professor Joanna Bryson, philosopher and cognitive scientist Susan Schneider, physicist Max Tegmark, philosopher Peter Singer, and bioethicist Glenn Cohen all weigh in on the question of AI rights.
- Given the grave tragedy of slavery throughout human history, philosophers and technologists must answer this question ahead of technological development to avoid humanity creating a slave class of conscious beings.
- One potential safeguard against that? Regulation. Once we define the context in which AI requires rights, the simplest solution may be to not build that thing.
Duke University researchers might have solved a half-century old problem.
- Duke University researchers created a hydrogel that appears to be as strong and flexible as human cartilage.
- The blend of three polymers provides enough flexibility and durability to mimic the knee.
- The next step is to test this hydrogel in sheep; human use can take at least three years.
Duke researchers have developed the first gel-based synthetic cartilage with the strength of the real thing. A quarter-sized disc of the material can withstand the weight of a 100-pound kettlebell without tearing or losing its shape.
Photo: Feichen Yang.<p>That's the word from a team in the Department of Chemistry and Department of Mechanical Engineering and Materials Science at Duke University. Their <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202003451" target="_blank">new paper</a>, published in the journal,<em> Advanced Functional Materials</em>, details this exciting evolution of this frustrating joint.<br></p><p>Researchers have sought materials strong and versatile enough to repair a knee since at least the seventies. This new hydrogel, comprised of three polymers, might be it. When two of the polymers are stretched, a third keeps the entire structure intact. When pulled 100,000 times, the cartilage held up as well as materials used in bone implants. The team also rubbed the hydrogel against natural cartilage a million times and found it to be as wear-resistant as the real thing. </p><p>The hydrogel has the appearance of Jell-O and is comprised of 60 percent water. Co-author, Feichen Yang, <a href="https://today.duke.edu/2020/06/lab-first-cartilage-mimicking-gel-strong-enough-knees" target="_blank">says</a> this network of polymers is particularly durable: "Only this combination of all three components is both flexible and stiff and therefore strong." </p><p> As with any new material, a lot of testing must be conducted. They don't foresee this hydrogel being implanted into human bodies for at least three years. The next step is to test it out in sheep. </p><p>Still, this is an exciting step forward in the rehabilitation of one of our trickiest joints. Given the potential reward, the wait is worth it. </p><p><span></span>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a>, <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a> and <a href="https://derekberes.substack.com/" target="_blank">Substack</a>. His next book is</em> "<em>Hero's Dose: The Case For Psychedelics in Ritual and Therapy."</em></p>
What would it be like to experience the 4th dimension?
Physicists have understood at least theoretically, that there may be higher dimensions, besides our normal three. The first clue came in 1905 when Einstein developed his theory of special relativity. Of course, by dimensions we’re talking about length, width, and height. Generally speaking, when we talk about a fourth dimension, it’s considered space-time. But here, physicists mean a spatial dimension beyond the normal three, not a parallel universe, as such dimensions are mistaken for in popular sci-fi shows.
An algorithm may allow doctors to assess PTSD candidates for early intervention after traumatic ER visits.
- 10-15% of people visiting emergency rooms eventually develop symptoms of long-lasting PTSD.
- Early treatment is available but there's been no way to tell who needs it.
- Using clinical data already being collected, machine learning can identify who's at risk.
The psychological scars a traumatic experience can leave behind may have a more profound effect on a person than the original traumatic experience. Long after an acute emergency is resolved, victims of post-traumatic stress disorder (PTSD) continue to suffer its consequences.
In the U.S. some 30 million patients are annually treated in emergency departments (EDs) for a range of traumatic injuries. Add to that urgent admissions to the ED with the onset of COVID-19 symptoms. Health experts predict that some 10 percent to 15 percent of these people will develop long-lasting PTSD within a year of the initial incident. While there are interventions that can help individuals avoid PTSD, there's been no reliable way to identify those most likely to need it.
That may now have changed. A multi-disciplinary team of researchers has developed a method for predicting who is most likely to develop PTSD after a traumatic emergency-room experience. Their study is published in the journal Nature Medicine.
70 data points and machine learning
Image source: Creators Collective/Unsplash
Study lead author Katharina Schultebraucks of Columbia University's Department Vagelos College of Physicians and Surgeons says:
"For many trauma patients, the ED visit is often their sole contact with the health care system. The time immediately after a traumatic injury is a critical window for identifying people at risk for PTSD and arranging appropriate follow-up treatment. The earlier we can treat those at risk, the better the likely outcomes."
The new PTSD test uses machine learning and 70 clinical data points plus a clinical stress-level assessment to develop a PTSD score for an individual that identifies their risk of acquiring the condition.
Among the 70 data points are stress hormone levels, inflammatory signals, high blood pressure, and an anxiety-level assessment. Says Schultebraucks, "We selected measures that are routinely collected in the ED and logged in the electronic medical record, plus answers to a few short questions about the psychological stress response. The idea was to create a tool that would be universally available and would add little burden to ED personnel."
Researchers used data from adult trauma survivors in Atlanta, Georgia (377 individuals) and New York City (221 individuals) to test their system.
Of this cohort, 90 percent of those predicted to be at high risk developed long-lasting PTSD symptoms within a year of the initial traumatic event — just 5 percent of people who never developed PTSD symptoms had been erroneously identified as being at risk.
On the other side of the coin, 29 percent of individuals were 'false negatives," tagged by the algorithm as not being at risk of PTSD, but then developing symptoms.
Image source: Külli Kittus/Unsplash
Schultebraucks looks forward to more testing as the researchers continue to refine their algorithm and to instill confidence in the approach among ED clinicians: "Because previous models for predicting PTSD risk have not been validated in independent samples like our model, they haven't been adopted in clinical practice." She expects that, "Testing and validation of our model in larger samples will be necessary for the algorithm to be ready-to-use in the general population."
"Currently only 7% of level-1 trauma centers routinely screen for PTSD," notes Schultebraucks. "We hope that the algorithm will provide ED clinicians with a rapid, automatic readout that they could use for discharge planning and the prevention of PTSD." She envisions the algorithm being implemented in the future as a feature of electronic medical records.
The researchers also plan to test their algorithm at predicting PTSD in people whose traumatic experiences come in the form of health events such as heart attacks and strokes, as opposed to visits to the emergency department.