5 ms·

No, the next decade, the 1930s, was the philosophical goldrush. Von Neumann, Gödel, Turing, and Tarski published their collective destruction of the formalist a

No, the next decade, the 1930s, was the philosophical goldrush. Von Neumann, Gödel, Turing, and Tarski published their collective destruction of the formalist and structuralist programs; Bohr, Heisenberg, and Pauli laid down the foundations of quantum mechanics. The former program destroyed any belief that we might be able to use formal tactics to analyze truth or other semantics; the latter program gave us positive evidence that reality is contextual and non-concrete.

mistrial9 6y ago
Niels Bohr was awarded the Nobel Prize in Physics in 1922 (?) Bohr Model of the Atom published in 1913
- Kednicma 6y ago
  This is fair. I was thinking of Bohr's work on establishing a proper school of QM. This is also why I didn't list Einstein et al.; he rejected that school and its work. It's true that many pre-QM concepts were laid down between 1890 and 1930, but the concepts that we embrace today are usually associated with the Copenhagen interpretation, which comes from Bohr's work in the 30s at his school. To be blunt and opinionated, I see the 1890s as asking the questions which we would answer in the 1930s. We found that set theory has gaping holes, and the answer turned out to be that all maths has gaping holes. We found that classical mechanics can't describe ovens, and it turns out that we need QM for describing lots of low-level physical phenomena.
libraryofbabel 6y ago
Foundations of Quantum Mechanics was really the 1920s as well: Bohr’s Copenhagen Interpretation, Heisenberg’s matrix mechanics, and the Schrodinger Equation are all from around 1925. Dirac Equation (relativistic QM) is from 1928. The parallels with work in the foundations of computing are certainly there, and interesting, but the initial breakthroughs were happening in different decades. :)
woodandsteel 6y ago
That was one line of thought that lead to the rejection of the Enlightenment view of the powers of human reason, but there were others.
pmoriarty 6y ago
None of the people you mention are philosophers, and their influence on philosophy is indirect at best.
- jimbokun 6y ago
  What's your criteria for designating someone a "philosopher"? Godel and Turing, at least would count in my mind.
- leephillips 6y ago
  They are not commonly classified as philosophers. However: Logic is often classed as a branch of philosophy, and that covers the Gödel work, and more, mentioned. There is plenty of writing, much of it by real philosophers, about how foundational work in QM, for example, did have profound philosophical implications and did influence the development of philosophy. The physicists who invented QM had many discussions about its philosophical implications, and these discussions have been studied by philosophers and influence philosophy. The division separating “philosophy” from mathematics, physics, and even logic is recent and arbitrary. And finally, if an academic philosopher finds math too hard, that is not a good reason to disqualify it from being considered “philosophy”.
- Kednicma 6y ago
  I am not a professional philosopher, so I will rely on the collected knowledge of the Stanford Encyclopedia of Philosophy [0]. Of the logicians/computational theorists I mentioned, three have their own entries [1][2][3] and are each associated with their own philosophical bodies of work. Von Neumann lacks his own page, but makes up for it by being a recurring secondary character in stories of Russell and Gödel. The QM physicists fare similarly, but are not credited as Great Men. I am okay with this. Bohr is discussed alongside his Copenhagen school [4], Heisenberg alongside his Uncertainty Principle [5]; but Pauli does not get a full page, being split between [4] and [6], a second Bohr page. While I haven't shown that these folks are central to philosophy, I think that I've shown that some philosophers definitely consider them to be directly influential upon some part of the practice. [0] https://plato.stanford.edu/ https://plato.stanford.edu/ [1] https://plato.stanford.edu/entries/goedel/ https://plato.stanford.edu/entries/goedel/ [2] https://plato.stanford.edu/entries/turing/ https://plato.stanford.edu/entries/turing/ [3] https://plato.stanford.edu/entries/tarski/ https://plato.stanford.edu/entries/tarski/ [4] https://plato.stanford.edu/entries/qm-copenhagen/ https://plato.stanford.edu/entries/qm-copenhagen/ [5] https://plato.stanford.edu/entries/qt-uncertainty/ https://plato.stanford.edu/entries/qt-uncertainty/ [6] https://plato.stanford.edu/entries/bohr-correspondence/ https://plato.stanford.edu/entries/bohr-correspondence/
hyperpape 6y ago
I'm not sure quite what you mean by "analyze". Whatever meaning you're using, there is something called "Tarski's theory of truth", it uses formal tactics extensively, and describes how to do formal semantics for a language.
- Kednicma 6y ago
  Please do read further on Tarski's work. Specifically, Tarski's Undefinability of Truth is a formal result which says that the typical language that we use to describe the world is so powerful that it cannot define its own notion of truth when analyzed formally. It is part of a family of results which destabilized the logicist dreams of the era and led to our modern vision of mathematics as a branching tree of many different logics. Edit: https://www.logicmatters.net/resources/pdfs/godelbook/GodelBookLM.pdf https://www.logicmatters.net/resources/pdfs/godelbook/GodelB... is quite good and includes Tarski's results. There's also GEB, of course.
  - hyperpape 6y ago
    What you said was "The former program destroyed any belief that we might be able to use formal tactics to analyze truth or other semantics." That description is quite vague, which was what my question suggested. Tarski's work described a criterion for a theory of truth for a language, and showed how to give a compositional semantics for some formal languages. As you noted, that language does not define its own truth predicate, to avoid paradox, but this is a formal analysis of truth. His work, along with Gödel's, ended the logicist program, but not formal treatments of semantic concepts. P.S. Don't assume what others have or haven't read. I can't claim any expertise, but I took a graduate seminar on the theory of truth taught by Anil Gupta. That doesn't mean I'm right, of course.
noslenwerdna 6y ago
Quantum mechanics doesn't provide "positive evidence that reality is contextual and non-concrete." 1) A quantum state can exist in a superposition of different states, but once measured, it collapses into one and only one state. If measured again it will still be in that state. So it is "concrete" in that sense. 2) "Contextual" is a word usually used to describe language, not physical measurements. However, if you mean that the state of a system depends on the state of every other system around it, then that, too, is not correct. Special relativity and the speed-of-light speed limit place hard constraints on what can affect an event at a specified time and place.
- Kednicma 6y ago
  Recall that "ontic" and "epistemic" are how we distinguish real facts about reality from observer-dependent knowledge about reality. On your (1), the typical interpretations for QM say that the wavefunction is not ontic, and this is directly traceable to the Copenhagen school of thought. QM is best done when we consider that our knowledge of systems is always partial; it turns out that often, the system itself is also partial about knowledge of own state. I greatly enjoyed reading [0] recently for a coverage of a toy theory exploring this distinction in more detail. On your (2), quantum contextuality [1] means something more subtle than your phrasing; it means that the state of a system is not the entirety of what is measured by an observer. To use your phrasing and state something very strong, the Free Will Theorem [2] says that the state of a system informs, but can never totally control, the way that a particle chooses to reply to an observer taking a measurement. This both opens the door for new avenues in free-will philosophy while slamming shut the idea that e.g. determinism can be meaningful or possible. [0] https://arxiv.org/abs/quant-ph/0401052 https://arxiv.org/abs/quant-ph/0401052 [1] https://en.wikipedia.org/wiki/Quantum_contextuality https://en.wikipedia.org/wiki/Quantum_contextuality [2] https://en.wikipedia.org/wiki/Free_will_theorem https://en.wikipedia.org/wiki/Free_will_theorem
  - noslenwerdna 6y ago
    Thanks for your thoughtful response. I must say [0] does look interesting, though I've only glanced over it. I would just point out that, a) it's not observer dependent, it's measurement dependent. If you collapse a wave-function in a superposition of states into state A, when I measure it, it will be state A as well. In that sense it is very concrete. b) surely you can see my confusion at your statement on contextual vs. quantum contextuality. For latter is a technical term, but the former was used in a non-technical way.

mistrial9 6y ago

Niels Bohr was awarded the Nobel Prize in Physics in 1922 (?) Bohr Model of the Atom published in 1913

Kednicma 6y ago
This is fair. I was thinking of Bohr's work on establishing a proper school of QM. This is also why I didn't list Einstein et al.; he rejected that school and its work. It's true that many pre-QM concepts were laid down between 1890 and 1930, but the concepts that we embrace today are usually associated with the Copenhagen interpretation, which comes from Bohr's work in the 30s at his school. To be blunt and opinionated, I see the 1890s as asking the questions which we would answer in the 1930s. We found that set theory has gaping holes, and the answer turned out to be that all maths has gaping holes. We found that classical mechanics can't describe ovens, and it turns out that we need QM for describing lots of low-level physical phenomena.

libraryofbabel 6y ago

Foundations of Quantum Mechanics was really the 1920s as well: Bohr’s Copenhagen Interpretation, Heisenberg’s matrix mechanics, and the Schrodinger Equation are all from around 1925. Dirac Equation (relativistic QM) is from 1928. The parallels with work in the foundations of computing are certainly there, and interesting, but the initial breakthroughs were happening in different decades. :)

woodandsteel 6y ago

That was one line of thought that lead to the rejection of the Enlightenment view of the powers of human reason, but there were others.

pmoriarty 6y ago

None of the people you mention are philosophers, and their influence on philosophy is indirect at best.

jimbokun 6y ago
What's your criteria for designating someone a "philosopher"? Godel and Turing, at least would count in my mind.
leephillips 6y ago
They are not commonly classified as philosophers. However: Logic is often classed as a branch of philosophy, and that covers the Gödel work, and more, mentioned. There is plenty of writing, much of it by real philosophers, about how foundational work in QM, for example, did have profound philosophical implications and did influence the development of philosophy. The physicists who invented QM had many discussions about its philosophical implications, and these discussions have been studied by philosophers and influence philosophy. The division separating “philosophy” from mathematics, physics, and even logic is recent and arbitrary. And finally, if an academic philosopher finds math too hard, that is not a good reason to disqualify it from being considered “philosophy”.
Kednicma 6y ago
I am not a professional philosopher, so I will rely on the collected knowledge of the Stanford Encyclopedia of Philosophy [0]. Of the logicians/computational theorists I mentioned, three have their own entries [1][2][3] and are each associated with their own philosophical bodies of work. Von Neumann lacks his own page, but makes up for it by being a recurring secondary character in stories of Russell and Gödel. The QM physicists fare similarly, but are not credited as Great Men. I am okay with this. Bohr is discussed alongside his Copenhagen school [4], Heisenberg alongside his Uncertainty Principle [5]; but Pauli does not get a full page, being split between [4] and [6], a second Bohr page. While I haven't shown that these folks are central to philosophy, I think that I've shown that some philosophers definitely consider them to be directly influential upon some part of the practice. [0] https://plato.stanford.edu/ https://plato.stanford.edu/ [1] https://plato.stanford.edu/entries/goedel/ https://plato.stanford.edu/entries/goedel/ [2] https://plato.stanford.edu/entries/turing/ https://plato.stanford.edu/entries/turing/ [3] https://plato.stanford.edu/entries/tarski/ https://plato.stanford.edu/entries/tarski/ [4] https://plato.stanford.edu/entries/qm-copenhagen/ https://plato.stanford.edu/entries/qm-copenhagen/ [5] https://plato.stanford.edu/entries/qt-uncertainty/ https://plato.stanford.edu/entries/qt-uncertainty/ [6] https://plato.stanford.edu/entries/bohr-correspondence/ https://plato.stanford.edu/entries/bohr-correspondence/

hyperpape 6y ago

I'm not sure quite what you mean by "analyze". Whatever meaning you're using, there is something called "Tarski's theory of truth", it uses formal tactics extensively, and describes how to do formal semantics for a language.

Kednicma 6y ago
Please do read further on Tarski's work. Specifically, Tarski's Undefinability of Truth is a formal result which says that the typical language that we use to describe the world is so powerful that it cannot define its own notion of truth when analyzed formally. It is part of a family of results which destabilized the logicist dreams of the era and led to our modern vision of mathematics as a branching tree of many different logics. Edit: https://www.logicmatters.net/resources/pdfs/godelbook/GodelBookLM.pdf https://www.logicmatters.net/resources/pdfs/godelbook/GodelB... is quite good and includes Tarski's results. There's also GEB, of course.
- hyperpape 6y ago
  What you said was "The former program destroyed any belief that we might be able to use formal tactics to analyze truth or other semantics." That description is quite vague, which was what my question suggested. Tarski's work described a criterion for a theory of truth for a language, and showed how to give a compositional semantics for some formal languages. As you noted, that language does not define its own truth predicate, to avoid paradox, but this is a formal analysis of truth. His work, along with Gödel's, ended the logicist program, but not formal treatments of semantic concepts. P.S. Don't assume what others have or haven't read. I can't claim any expertise, but I took a graduate seminar on the theory of truth taught by Anil Gupta. That doesn't mean I'm right, of course.

noslenwerdna 6y ago

Quantum mechanics doesn't provide "positive evidence that reality is contextual and non-concrete." 1) A quantum state can exist in a superposition of different states, but once measured, it collapses into one and only one state. If measured again it will still be in that state. So it is "concrete" in that sense. 2) "Contextual" is a word usually used to describe language, not physical measurements. However, if you mean that the state of a system depends on the state of every other system around it, then that, too, is not correct. Special relativity and the speed-of-light speed limit place hard constraints on what can affect an event at a specified time and place.

Kednicma 6y ago
Recall that "ontic" and "epistemic" are how we distinguish real facts about reality from observer-dependent knowledge about reality. On your (1), the typical interpretations for QM say that the wavefunction is not ontic, and this is directly traceable to the Copenhagen school of thought. QM is best done when we consider that our knowledge of systems is always partial; it turns out that often, the system itself is also partial about knowledge of own state. I greatly enjoyed reading [0] recently for a coverage of a toy theory exploring this distinction in more detail. On your (2), quantum contextuality [1] means something more subtle than your phrasing; it means that the state of a system is not the entirety of what is measured by an observer. To use your phrasing and state something very strong, the Free Will Theorem [2] says that the state of a system informs, but can never totally control, the way that a particle chooses to reply to an observer taking a measurement. This both opens the door for new avenues in free-will philosophy while slamming shut the idea that e.g. determinism can be meaningful or possible. [0] https://arxiv.org/abs/quant-ph/0401052 https://arxiv.org/abs/quant-ph/0401052 [1] https://en.wikipedia.org/wiki/Quantum_contextuality https://en.wikipedia.org/wiki/Quantum_contextuality [2] https://en.wikipedia.org/wiki/Free_will_theorem https://en.wikipedia.org/wiki/Free_will_theorem
- noslenwerdna 6y ago
  Thanks for your thoughtful response. I must say [0] does look interesting, though I've only glanced over it. I would just point out that, a) it's not observer dependent, it's measurement dependent. If you collapse a wave-function in a superposition of states into state A, when I measure it, it will be state A as well. In that sense it is very concrete. b) surely you can see my confusion at your statement on contextual vs. quantum contextuality. For latter is a technical term, but the former was used in a non-technical way.