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Making Sense of Quantum Mechanics

I’ll always be grateful to David Albert. In the early 1990s, when I was struggling to write an article called “Quantum Philosophy,” Albert, a philosopher of physics who specializes in quantum mechanics, took pity on me. He served as my guide through the netherworld of quantum interpretations, elucidating the relative merits of the Copenhagen, Bohmian pilot-wave and many-worlds interpretations. He told me about his own ideas too, including a many-worlds variant that involves many minds, and speculation on on how artificial intelligences based on quantum computation might differ from our own minds. Albert, who’s at Columbia, belongs to a philosophy salon to which I belong in New York City, and he always elevates the chitchat. He is erudite without being pedantic, by which I mean that he cuts through the bullshit, a trait that I, the amateur, appreciate. To see what I mean, check out his 2012 critique of a pop-physics book, one of my all-time favorite takedowns, and a preprint of his new paper “How to Teach Quantum Mechanics.” Interest in quantum mechanics has surged recently because of books like Beyond Weird by Philip Ball and What Is Real? by Adam Becker (for whom Albert served as a source). I thought it would be a good time to consult my trusty guide. – John Horgan

Horgan: You have a doctorate in physics, but you became a philosopher. Why? Did you decide physics is too hard?

Albert: Well, yeah – in a sense.  What was too hard (in particular) was getting somebody to hire me to think about the sorts of questions that interested me in a physics department that was located in a place where I wanted to live.  Thinking about foundational questions – which were the sorts of questions that I was interested in, and the sorts of questions that I felt I was good at thinking about – was very much out of fashion, and very much frowned upon, in most physics departments back in the early 1980’s.  But not so in philosophy departments.  So what it came down to, at the time, was that if I wanted to work in a physics department I was going to have to live in South Carolina, but if I was willing to work in a philosophy department I could live in New York.

Horgan: Good choice. What is the point, in our scientific age, of philosophy?

Albert: I’m not sure I see the connection.  It’s like asking, “What is the point, in our scientific age, of ice cream?”  People like it.  People – or some people – want to understand how things, in the broadest possible sense of the term, hang together.  And it happens (moreover) that the business of trying to figure that out has had obvious and enormous and innumerable consequences for the history of the world.  And if the thought is that what goes on in university science departments has lately somehow taken that function over, then that’s just clearly and wildly wrong – and the fact that it’s wrong, as I explained in my answer to your previous question, was part of the reason why I moved from a science department to a philosophy department.   

Horgan: Ice cream? Mmm. What is philosophy’s chief contribution to humanity?

Albert: Clarity.  Wonder.  A certain kind of anxiety.  The obvious and enormous and innumerable consequences for the history of the world that I mentioned above.  I don’t know.

Horgan: You demolished Lawrence Krauss’s A Universe from Nothing in 2012, pointing out that a quantum field, which Krauss said generated the cosmos, isn’t nothing. Here’s my question: Will science ever tell us why there is something rather than nothing?

Albert: I can’t see how that would work.  The question itself – the question (that is) of “Why is there something rather than nothing?” – seems to me to be predicated on a false or confused understanding of what it is to explain something, or what it is (at any rate) to explain something scientifically.  Scientific explanations (that is: scientific answers to “why” questions) are ways of showing us how to get from certain aspects of how things are to other aspects of how things are.  One explains certain aspects of how things are in terms of certain other aspects of how things are.  One explains (for example) where a projectile eventually lands in terms of its initial position and velocity, and its mass, and the atmospheric conditions, and the gravitational conditions, and the laws of physics.  One explains the rise of Trump in terms of the stagnation of wages, or in terms of the ubiquity of reality TV, or I don’t know what.  And so there need to be certain aspects of how things are already on the table (you might say) in order for anything like a scientific explanation even to get started.  And I can’t imagine what those would be – the ones that are already on the table – in the case of an “explanation” of why there is something rather than nothing.

Horgan: I’ll take that as a no. You’ve spent a lot of time pondering quantum mechanics. Have you figured it out yet?

Albert: Yup.  Sort of.  I think I understand it much better than I used to, and better than I used to imagine I ever would.

Horgan: What’s your favorite interpretation of quantum mechanics, and why?

Albert: Once upon a time, physics aspired to offer us an objective and literal and realistic and comprehensive and mechanical account of what the world is actually like.  And that aspiration suddenly began to look quaint and naïve and hopeless, in the early decades of the 20th century, under the fantastic assault of quantum mechanics.  And the interpretations of quantum mechanics that I like (although “interpretation” is really the wrong word here – since the various so-called “interpretations” on offer are really different physical theories, which often make different empirical predictions) are the ones that show, by explicit example, that an account like that can still be had – interpretations (that is) like Bohmian Mechanics, and theories of spontaneous localization.  And among those I have no favorite.  I think all of them are interesting, and promising, and since they make different predictions about the outcomes of certain performable experiments, it will be up to those experiments, and not to philosophers like myself, to decide which of them, if any, are actually true.

But there is a further puzzle here – something (as it were) more fine-grained, something that it has only fairly recently occurred to people to wonder about.  All of the “interpretations” I mentioned above make crucial use of something called the quantum-mechanical wave-function.  And there is a question – even once we have settled on one or another of those “interpretations” – about what sorts of things quantum-mechanical wave-functions are.  And various possible answers to that question have been hotly debated for 15 or 20 years now.  Everybody has always agreed that the simplest and most flat-footed and most obvious way to think about what wave-functions are is to think of them as concrete physical objects.  But the space that wave-functions live in, the space (that is) that we would be obliged to think of as the fundamental physical space of the world– if we want to think of wave-functions as concrete physical objects – happens to have a gigantic number of dimensions.  And this has always seemed to everybody to amount to a problem.  And I have lately become convinced that it is nothing of the sort.  I have lately become convinced that (as a matter of fact) it is the key to the whole business.  It turns out that if you imagine that the fundamental physical space of the world is something other, and larger, and different than the three-dimensional space of our everyday experience, then everything that has always seemed uncanny about quantum mechanics suddenly becomes clear and straightforward and understandable and in some sense to have been expected.  Anyway, that’s the work that I was thinking of in my response to your previous question. [For more details see this preprint.]

Horgan: Why does quantum mechanics inspire so much New Age nonsense?

Albert: Precisely (I guess) because quantum mechanics had for so long been understood – incorrectly – to have overthrown every hope of understanding the world in an objective and literal and realistic and mechanical way.

Horgan: Is consciousness a solvable problem?

Albert: I sort of feel the ground coming out from under me when I try to think about that.  I can’t understand how physics could possibly give us a fully satisfactory account of consciousness, and I can’t understand how physics could possibly fail, at the end of the day, to give us a fully satisfactory account of consciousness.  

Horgan: Are you a member of the Singularity cult?

Nope.

Horgan: I’m glad. Nietzsche said “there are absolutely no moral facts” and “what moral and religious judgments have in common is belief in things that aren’t real.” Was he right? Do moral rules have anything remotely approaching the status of scientific and mathematical truths?

Albert: I guess I think not.  I guess (that is) that I think that moral rules have a very different sort of nature, and a very different sort of status, than scientific and mathematical truths.  But a colleague of mine (Justin Clarke-Doane) has a cute argument to the effect that the epistemic status of mathematical truths can’t be much different from the epistemic status of ethical ones. 

Horgan: Why are most philosophical papers so damned hard to understand? Are you trying to keep out the riff-raff?

Albert: They’re not so hard to understand, and where they are it’s just because people are trying their best to be careful, and to get things right.  Do you ask Quantum Field Theorists why their papers are so dammed hard to understand?

Horgan: I guess I don’t. Is it fair to expect philosophers to be wiser and more ethical than non-philosophers?

Albert: It feels like it would be more to the point to expect that of our leaders.

Horgan: Fair point. What’s your utopia?

Albert: I see that some of your other respondents talked about someplace where they could sit around in bathing suits and have nice conversations with interesting people.  I like that too.

Further Reading:

For an alternative take on quantum mechanics, see “Tragedy and Telepathy,” a chapter in my free online book Mind-Body Problems.

David Bohm, Quantum Mechanics and Enlightenment

Do Our Questions Create the World?

Science Will Never Explain Why There’s Something Rather Than Nothing

What Is Philosophy’s Point? Part 1

Was Thomas Kuhn Evil?

See also my Q&As with Scott AaronsonDavid ChalmersNoam ChomskyDavid DeutschGeorge Ellis,Marcelo GleiserRobin HansonNick Herbert,Jim Holt,Sabine Hossenfelder,Stuart KauffmanChristof Koch,Garrett Lisi,Tim MaudlinPriyamvada NatarajanNaomi Oreskes,Martin ReesCarlo Rovelli,Rupert SheldrakeLee SmolinSheldon SolomonPaul SteinhardtPhilip Tetlock,Tyler Volk,Steven Weinberg,  Edward WittenPeter WoitStephen Wolfram and Eliezer Yudkowsky.



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