This is the third part of a series examining the Many Worlds Interpretation of Quantum Mechanics (the MWI of QM). The popularity of the MWI in books, blogs, and science videos, especially among the science-minded, tends to keep in present in some corner of my mind. Blog posts are a way to shoo it out.
The first part introduced the topic and talked about cats. The second part discussed the Schrödinger equation, wavefunctions, decoherence, and the question of how multiple instances of matter can coincide. That question, to me, is a central issue I have with MWI.
This time I dig into quantum superposition and touch on a few other topics.
Last time I started exploring questions I have about the Many Worlds Interpretation of Quantum Mechanics (the MWI of QM). Obviously I’m not a fan; quite the opposite. It presents as parsimonious, hung on the single hook of a universal wavefunction, but I think it gets more complicated and cumbersome when examined. I can’t say it’s broken, but I don’t find it very attractive.
I suspect most people, even in physics, don’t care. A few have invested themselves in books or papers, but these interpretations don’t matter to real physics work. The math is the math. But among the philosophical, especially the ontological, it’s food for debate.
Being both philosophical and ontological, I do smell what’s cooking!
Back in January, in a post about unanswered questions in physics, I included the Many Worlds Interpretation of Quantum Mechanics (the MWI of QM). I wish I hadn’t. Including it, and a few other more metaphysical topics, took space away from the physical topics.
I did it because I’ve had notes for an MWI: Questions post for a long time, but shoehorning it in like that was a mistake. Ever since, I’ve wanted to return and give it the attention of a full post. I’m reminded about it constantly; the concept of “many worlds” has become such a part of our culture that I encounter it frequently in fiction and in fact (and in other blog posts).
Its appeal is based on a simplicity, but to me it doesn’t seem at all that simple.
Among those who study the human mind and consciousness, there is what is termed “The Hard Problem.” It is in contrast to, and qualitatively different from, problems that are merely hard. (Simply put, The Hard Problem is the question of how subjective experience arises from the physical mechanism of the brain.)
This post isn’t about that at all. It’s not even about the human mind (or about politics). This post is about good old fundamental physics. That is to say, basic reality. Some time ago, a friend asked me what was missing from our picture of physics. This is, in part, my answer.
There is quite a bit, as it turns out, and it’s something I like to remind myself of from time to time, so I made a list.
I’ve posted more than once regarding my view of the Many Worlds Interpretation (MWI) of quantum physics. I find its rise in modern popularity genuinely inexplicable. (I can’t help but think it’s exactly the sort of thing Dr. Sabine Hossenfelder is talking about in her book, Lost in Math.)
Hoping to find the logic that apparently appeals to so many, I read Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime (2019), by Sean Carroll. It is, in large part, his argument favoring the MWI. Carroll is a leading voice in promoting the view, so I figured his book would address my concerns.
But as far as I can tell, “there is no there there.”
I’ve come to realize that, when it comes to the Many Worlds Interpretation (MWI) of quantum physics, there is at least one aspect of it that’s poorly understood. Since it’s an aspect that even proponents of MWI recognize as an issue, I thought I’d take a stab at explaining it. (If nothing else, I’ll have a long reply I can link to in the future.)
The issue in question involves what MWI does to probability. Essentially, our view of rare events — improbable events — is that they happen rarely, as we’d expect. Flip a fair coin 100 times; we expect to get heads roughly 50% of the time.
But under MWI, someone always gets 100 heads in a row.
I was surprised to discover I’ve never posted about the Many Worlds Interpretation (MWI) of quantum physics — I would have sworn I had. I’ve mentioned it a few times, and I know I’ve discussed it in comment sections, but it seems I never tackled the subject explicitly for the record.
It’s been on my mind lately because others have talked about it. Sean Carroll’s book promoting it generated a wave of discussion. The final push for me was Jim Baggott’s Farewell to Reality, which consigns MWI to the “fairy tale physics” heap.
Since I quite agree, this seems a good followup to yesterday’s post.
My voracious reading habit has deep roots in libraries. The love of reading comes from my parents, but libraries provided a vast smörgåsbord to browse and consume. Each week I’d check out as many books as I could carry. I discovered science fiction in a library (the Lucky Starr series, with Isaac Asimov writing as Paul French, is the first I remember).
Modern adult life, I got out of the habit of libraries (and into book stores and now online books). But now the Cloud Library has reinvigorated my love of all those free books, especially the ones I missed along the way.
For instance, Farewell to Reality: How Modern Physics Has Betrayed the Search for Scientific Truth (2014), by Jim Baggott.
This post, and several that follow, veer into fairly trivial territory. Which, I suppose, is relative. To some, all my posts may be trivial, whereas to me none of them are. At least not totally, although some are less con carne than others. As it turns out, this week I’m serving salads.
More accurately, cleaning out my closet or, even more accurately, collection of — not even half, but — lightly baked post ideas. I’m one who jots down thoughts in case they grow into something interesting. Some do, but others never grow much beyond the seed.
Case in point: the difference, if any, between aspects and properties.
It’s been a long time since I’ve written a Sci-Fi Saturday post. (I didn’t post at all in 2017, so it’s been a long time since I’ve written a lot of things.) But last night I watched Mr. Nobody (2009), a slightly surreal science fiction film that I found hugely engaging and affecting, and it inspired me to write about it.
The truth is that Mr. Nobody isn’t actually surrealism — it does have a concrete narrative, but it’s a jumbled, imaginary, and fantastic one. That can sometimes be the case with really good science fiction. A common trick SF authors play is keeping you guessing until they reveal their mysteries.
Mr. Nobody isn’t particularly mysterious, but it does require that you pay close attention!