The physics vs. philosophy slow-motion blogfight continues, the latest major contribution being Sean Carroll's "Physicists Should Stop Saying silly Things About Philosophy. I've been mostly trying to stay out of this, but when I read through the comments at Sean's post to see if anybody offered any specific examples of problems that could've been avoided by talking to philosophers, I was kind of surprised to find a lot of people talking up Niels Bohr. (Likewise Ashutosh Jogalekar's Philosophy Begins Where Physics Ends....) If you're trying to talk up the virtues of philosophy over "pure" physics, I'm not sure Bohr's your guy. Not because Bohr wasn't philosophically inclined-- Werner Heisenberg famously described Bohr as "primarily a philosopher, not a physicist"-- but because I'm not convinced he was all that good at it.
If you asked me to draw up a list of the primary virtue of philosophy, I'd end up pointing toward a kind of intellectual precision. The thing that the best philosophers seem to do that is worth emulating is to think extremely carefully about what things mean, and work through the implications of those meanings. (This is also the thing that makes philosophy so tedious to read, because there's a hundred pages of term-defining before you get to the interesting new stuff, but that's a separate issue...) Philosophy at its best goes back to first principles, and verifies that those are, in fact, the first principles, before embarking on a clear and logical progression from those principles through their application to interesting problems.
And, you know, clarity of thought and expression just wasn't Bohr's thing. He was famous for his dithering equivocation (Graham Farmelo's Dirac biography tells a story about the one time Dirac was asked to work with Bohr on a paper. After several false starts and much waffling, Dirac offered "In school, I was taught that one should not begin a sentence until one knows where it will end.") This shows up most spectacularly in Bohr's attempted response to the Einstein, Podolsky, and Rosen paper of 1935. Admittedly, this is a tough problem to answer, and he was a bit rushed in producing it, but Bohr's paper is a hopeless muddle, and his responses didn't get much better when he had more time to think about them.
His primary philosophical contributions are the Copenhagen Interpretation and the principle of "complementarity," the idea of incompatible pairs of observables like the particle and wave natures of a quantum object. Nobody other than Bohr seems to have done much with complementarity other than attribute it to Bohr, because it doesn't seem to have a very precise definition. It's tempting to cynically suggest that complementarity meant basically whatever Bohr needed it to mean at the time he invoked it. (Later in life, he apparently tried to extend his philosophy of complementarity outside the physical sciences, which almost nobody talks about because it's kind of embarrassing)
As for the Copenhagen Interpretation, that's also kind of a mess, particularly during Bohr's day, a shambling creature stitched together from ad hoc rules. It demands an absolute separation between microscopic systems obeying quantum rules and macroscopic ones that behave classically, and a quasi-magical collapse of the wavefunction that was never adequately defined.
Bohr was also somewhat prone to weird and poorly motivated enthusiasms. For a while during the "old quantum theory" period, he was adamantly opposed to the quantization of light, for reasons that seem to have been mostly aesthetic (this proved untenable, but not until after some fairly bad work). Having succeeded with one revolutionary overthrow of classical physics on grand philosophical terms, he kept holding out hope for another. He wanted to discard the idea of energy conservation as anything other than a statistical principle in order to deal with the problem of beta decay (Pauli solved this by introducing the neutrino). And when the problems of QED became clear, Bohr kept pushing for a grand and revolutionary solution, when the actual answer proved to be surprisingly conservative-- the basic idea of renormalization was kicked around in the early 1930's, but demanded a more systematic and mathematically sophisticated approach that wasn't widely appreciated until the late 1940's.
Bohr's philosophical pursuits are important mostly in an inspirational sort of sense. That is, they became useful once other people got hold of them and sharpened Bohr's hopelessly vague notions into something, well, philosophical. The best example is obviously Bell, who worked through the implications of the Local Hidden Variable models preferred by people like Einstein, contrasting them to the more orthodox quantum theory, and ending up with something precise, mathematically sound, and most importantly testable. Bell was inspired in large part by the work of David Bohm on an alternative interpretation of quantum mechanics where particles have well-defined trajectories shaped by a non-local guiding potential. And the Copenhagen Interpretation remained kind of muddled until things like Everett's Many-Worlds Interpretation (which Sean evangelizes for here) and the general program of research into decoherence (which I tend to associate with Zurek, but he's one of many) forced it to take on a more definite shape.
So, while Bohr was unquestionably trying to do philosophical sorts of things, I'm not sure I'd claim that any of them were all that successful. Now, I suppose you can claim this as support for the pro-philosophy camp in the sense that the things Neil deGrasse Tyson and others have called out as airy piffle aren't any more airily piffilicious than Bohr's work, and that ended up all right. Which, you know, I guess you can do, but it doesn't mean that Bohr's stuff wasn't airy piffle. If you want to valorize people for thinking philosophically about physics, you'd be better off going with folks like Bell and Bohm, who brought some clarity and precision to the subject, like philosophers are supposed to do.
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I think part of the problem is that we don't have a universally agreed definition of what philosophy is. (Cue Inigo Montoya.) You have made a reasonable attempt at a rigorous definition, but the word is commonly used in English to mean other things. And as with all living languages, meaning changes with time. Compare Shakespeare's lines: "There are more things in heaven and earth, Horatio/Than are dreamt of in your philosophy." Here, "philosophy" includes what we now called science (which was called "natural philosophy" in English until the mid 19th century, and is still called that--Naturwissenschaft--in German).
I think a better example of a 20th century philosopher scientist would be Einstein, whose Gedankenexperimente explored some of the consequences of his theories. The conundrum of Schrödinger's cat is another good example of philosophy in science.
One should be loathe to trust a scientist wearing a necktie, much less a suit coat. Robes and bonnets are philosophical haberdashery affected by charlatans who cannot afford highest quality attire invisible to all but cognoscenti.
Tommy Aquinas proved the existence of God by exhaustive citation supporting postulate. Baruch Spinoza set out to rigorously derive God's existence, achieving elegant disproof. Thomas Edison invented the light bulb.
Night is dark so you can imagine your fears without distraction.
Philosophy used to be called Meta-physics, i.e. everything else other than Physics.
It is all the reasoning that is extra to (outside of) the equations and relationships that exist within physics.
Unfortunately the lines are becoming blurred as physics gets more complex, and the philosophy that people use, or meta-physics if you want to call it that depends on the complexity, and a persons intelligence (or ability) to deal with that complexity, i.e. their processing power that their mind has in visualising higher dimensional complex relationships. Simple people simplify relationships, and only deal with those relationships in simple ways.
Yes Horatio, how many of the higher dimensions can you deal with? How many can you see and their interactions?
With physics, going to quantum mechanics, the uncertainty principle (Heisenberg), Dark Energy, Dark Matter, there are loads of higher dimensions that people just cannot see their way into.
As we live in a paradox, you cannot disprove anything!
You cannot disprove that 2+2 doesn't =5
Unfortunately many people still don't understand why or understand what constraints/conventions they have applied to mathematics, restricting the possible answers.
Unfortunately physics, just as meta-physics, sorry, philosophy uses intellect, anyone can bias their beliefs and conclusions based on the limited picture they see of the universe, their environment, this world.
Are you implying that god played dice with Bohr's comments?
The odd thing about this discussion is that, within philosophy, everyone knows (from their first year undergraduate class) Kant's argument that metaphysics is impossible to study. A lot of philosophers agree, and the ones that don't certainly have strategies for addressing Kant's argument.
Now along comes a bunch of physicists talking about philosophy as if the important philosophical problems are metaphysical ones, to be considered from a naive realist point of view that completely ignores what Kant wrote.
I think the main value of philosophy of science is influencing the way scientists talk about science (not how they do science). For example, it's pretty common to hear scientists today talking about the non-falsifiability of whatever theory they believe to be pseudoscience. Philosophy of science moved past Popper quite a long time ago, but I'm sure scientists will catch up at some point. ;)
On a semi-related know, it could certainly be argued that Orzel's next book is a philosophy of science book. It sure sounds like the book is at least in part a discussion of what makes science science. And that's one of the central tasks of the philosophy of science.
To connect to my above point, I wouldn't be at all surprised if Orzel's book is sprinkled with the language of today's philosophy of science--if philosophers have done their job right.
God playing dice with Bohr comments?
The problem with philosophy, is that it is all based around the basic mathematical (logical) convention of
Define all the IFs as you like and see how all the THENs fall out.
What we have are a number of different populations working with so many different permutations of IFs, from which all their THENs have been established.
There is so much random noise in this world, that whilst may be interesting for a while or fill in the time of day, it is random noise. This is one of the throws of the dice, the randomness, the expenditure of energy achieving nothing but communication, but some communication is useful.
IF you want to define Bohr's comments as a throw of the proverbial dice, THEN you would be defining his comments as nothing more than random noise that could be forgotten about immediately and the world would not be better or worse off for it.
If you look at where chemistry science came from, what about phlogiston theory?
Science has always had philisophy as an essential part of it. It has too.
OK, help me out here. So philosophy has some utility in particular professions, it's just that philosophers (people who do philosophy for a living) have become toilers searching for relevance in a profession that's largely been superseded by advances in other fields.
Sounds to me like they're just having trouble accepting their demotion from Crowning Glory of Civilization and All-Around Source of Cutting Edge Thought to Docents of the Relics.
That about right?
There once was a very big employment of philosophers. They were called the "Court Jester". They would posit various arguments and then finally reveal how absurd any position, either way is ridiculous. You just have to know your Shakespeare.
Philosophers could be useful at times, but as with anyone or any profession, we could choose to live without them. E.g. we could all decide we don't want doctors and when we get sick, we don't get treatment. We could live without philosophers, but someone somewhere trains them, or they train themselves, and pays for their training or their costs of living. If there was no demand, they wouldn't exist, unless someone wants to be as one.
With all the advances in science, physics and chemistry and biology, neuroscience, psychology, the philosophy part of each has become subsumed into that science.
But don't forget, philosophy is actually a major part of all religions around the world.
I'm OK with that, BTW.
When I did a quick search to see if it was worth nominating "piffilicious" as the new word of the year, I discovered that there is a UK company with that name!
Can I still suggest it be promoted as a term for use in analysis of the upcoming wave of piffle during the current election cycle?
My only comment on your main argument, which I generally agree with, is that I'm not really sure if you can argue that Bohr's work turned out all right. In my mind, its mainvirtue was that, apart from getting the energy levels of H correct, it was almost entirely wrong. The success of the energy level prediction drove all sorts of experiments that proved, conclusively, that a semi-classical model cannot work. Desperation drove the invention of a completely new physics to deal with the clash between reality and theory.
That might be a good thing. Was it easier or harder to invent QED than non-relativistic quantum mechanics? It seems that it was harder, and that might be because the non-relativistic model got so many things correct whereas Bohr's model got so many things completely wrong.
I was thinking more of Bohr's philosophical noodling from the late 20's on than his original quantum model. The "old quantum theory" phase of the late teens and early 20's is very ad hoc, and not all that successful, but Bohr was deeply involved with the interpretation of the full quantum theory once it was worked out. And once Bell got hold of it, it turned out to be very productive. That's the stuff that "turned out all right."
I don't think any knowledgeable person would want to claim that Kant, Hegel, or Wittgenstein were all that clear or precise in their terminology, and, by most accounts, at least one of those guys is in the running for greatest philosopher ever.