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Why physicists need philosophy

At a party, on a plane, in the locker-room, I’m often asked what I do. Though tempted by one colleague’s adoption of the identity of a steam-pipe fitter, I admit I am a professor of philosophy. If that doesn’t end or redirect the conversation, my questioner may continue by raising some current moral or political issue, or asking for my favorite philosopher. The reply “No, I’m not that kind of philosopher, my field is the philosophy of physics” typically induces silence as my interlocutor peers into the chasm separating C.P. Snow’s two cultures while I go on about how Einstein changed basic beliefs about space and time.

But now I have to be ready for a different response. “How can philosophers add anything to what physicists have been able to achieve without them? Richard Feynman made fun of philosophy, Steven Weinberg finds it useless, Neil de Grasse Tyson thinks it’s a waste of time, and Larry Krauss and Stephen Hawking say physics has answered big questions about our place in the universe that philosophers used to ask in ways contemporary philosophers simply can’t follow.” This response is a simple appeal to authority, based on scientific eminence, and lately on success in reaching a receptive mass market through popular books and TV shows. But expertise in one field is often not transferable to another, and popular science presentations are often more entertaining than enlightening.

Theoretical physicist Stephen Hawking last year presented a six-episode series of TV programs entitled “Genius.” With jazzy production technique, the series aimed to convince viewers of reality TV shows that they can reach the same answers to big questions as contemporary physicists. Hawking is notorious for his 2011 claim that philosophy is dead, so it is not surprising that his consultant “experts” included no philosopher. A pity: a little philosophical expertise could have provided the balance and coherence the series lacked.

Take the episode “Why are we here?” A medieval Christian would say “To serve God and seek salvation”: the US Declaration of Independence suggests an alternative purpose: the pursuit of happiness. Both count as reasons for being here, though neither offers the answer toward which the episode’s three “ordinary” participants are guided. The episode suggests two kinds of scientific explanations about why we’re here before settling on a third.

First, Laplacean determinism: every last detail of the present state of the universe (including the motions of our brains and bodies) is determined by its earlier state. This is deemed incompatible with our ability to freely choose what to do, with no mention of the long philosophical tradition of compatibilism (see my colleague Jenann Ismael’s recent book How Physics Makes Us Free.)

Second, quantum indeterminism, illustrated by the selective bombardment of our hapless trio triggered by random radioactive decay. Whether this would be any more compatible with free choice than determinism is not addressed.

So why are we here? Hawking professes his belief that understanding quantum theory requires acceptance of many worlds, (some) containing a different version of each of us. Our trio of participants joins an elaborate visual display of free choices by multiple actors, each wearing a face mask matching one of the participants. Initially the actors all line up behind the participant whose mask they wear. When alerted each chooses to step to one side or the other, progressively spreading the lines. Everyone in an initial line is a metaphor for a version of the same person: their position in line corresponds to the world they’re in.

What should we conclude? If their movements mimic the results of random quantum events, then in what sense are they freely chosen? If not, then how does the existence of many worlds help make the free choice of a person in any of them any more compatible with quantum physics? (The moral is supposed to be “I’m here because I’m in my world through my own previous free choices.”)

Hawking may believe there are many worlds, but plenty of physicists, mathematicians, and philosophers don’t. There is no consensus on how quantum theory should be understood. I doubt that most experts share Hawking’s belief. Behind a façade of experimental demonstration, the episode “Why are we here?” hides an appeal to authority. What is needed is the convincing argument that it is the job of the philosopher to provide.

Featured image credit: Provided by the author and used with permission.

Recent Comments

  1. Julien

    At the outset of your article, I was poised to gasp: “Finally, someone talks of this!”
    But I quickly discovered that you are too kind to the ignorant, arrogant, and dangerous (through the application of their half-way discoveries) “scientists”.
    You may like to tear down everyone who gives answers to the unanswerable questions. Such as: how does one define knowledge and knower, and what absolutes are supporting their methodology.
    A physicist is a child buried under the received lexicon, and a philosopher is one who only questions. If the latter gives answers to the unanswerable, they become “physicists”.
    Remember Kant? He had only one worthy question: “What are we?” And couldn’t answer it. Bravo to him!
    I hope you proceed to the demolition.

  2. Ld Elon

    It seems in the west, your main character influence is one geezer who takes credit for every others ideas/discoveries.
    Einstein
    Einstein
    Einstein
    Einstein
    Einstein
    Einstein
    Einstein
    Einstein
    Place on repeat>>>

  3. Jean-Claude Chetrit

    The author does not answer why we are here,
    nor why we should believe it. Maybe there is no reason, just like Darwin explanation of how we got here. Science is progressing and provides the only answers we can trust.

  4. Bhupinder Singh Anand

    Perhaps its time we distinguished explicitly between:

    • The natural scientist’s hat, whose wearer’s responsibility is recording—as precisely and as objectively as possible—our sensory observations and their associated perceptions (what some cognitive scientists, e.g., Lakoff and Nunez, term as `conceptual metaphors’) of a `common’ external world;

    • The philosopher’s hat, whose wearer’s responsibility is abstracting a coherent—albeit informal and not necessarily objective—holistic perspective (corresponding to Carnap’s explicandum) of the external world from our sensory observations; and

    • The mathematician’s hat, whose wearer’s responsibility is providing the tools for adequately expressing (corresponding to Carnap’s explicatum}) such recordings and abstractions in a symbolicl language of unambiguous communication.

  5. Julius Mazzarella

    Many Worlds is a bunch of Bull shit. Hawking may be smart but the Many Worlds evangelism is more of a fantasy than a theory. What decides when and how the “worlds” split? Are we to assume every particle in the universe has an infinite number of other universes one for each amplitude? or are they over lapped ? Who or what is overlapping them? And if no splitting occurs then no decision points are needed so why are they there to begin with? Many Worlds crap is a better way to describe it.

  6. Karl Young

    What a fantastic and elegant explanation of why all Graham’s number of me exist – oops there goes another Graham’s number cubed of me…

    Gee whiz it’s neat to know there are people who know everything (and thankfully will let you know they do).

  7. Sinem Sa

    I would like to ask how can free choice be related to existence? Then, how would it be possible to explain existence with conditions?

  8. Brian Lynchehaun

    This article is an excellent introductory paragraphs, but it ends rather abruptly before the meat of the discussion.

    Did you hit ‘post’ prematurely?

  9. Farhad Keyvan

    Thank you for this great article Professor Healey. You always bring fresh new perspectives to how physics and science in general are perceived. I never forget your exciting classrooms at UCLA. I loved all of our discussions.

  10. Stephen Goranson

    One problem I have with the many worlds proposal has to do with the concept of discrete forking paths. Some say, like a flip pf a coin, heads or tails. But what about how many times it flips, or lands on its side and rolls against a wall, or etc. What would be the boundaries of discrete options?

  11. J hernandez

    Existential questions like these should include both scientific and philosophical considerations. Science can explain the machinations of the universe but it’s starts to bleed into the philosophical realm when you ask the question “why.” Ultimately, perhaps the only right answer is the one you as an individual concludes as we are the center of our own universe and it ceases to exist when we do.

  12. Lucian Radu Teodorescu

    Thank you for the post!

    It gave me some additional arguments, in a quest to understand the power discourses that tend to articulate some of the sciences. Too much infatuation, too much transfer of authority, too many theories created with unsound foundations (I’m looking at you Universal Darwinism).

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