6 ms·

The chain reaction was still speculative. Also physics is math, but math is not physics.

by Isamu 2y ago

genman 2y ago
Physics is math, but not all math is physics.
- andrewflnr 2y ago
  Physics is, optimistically, math plus a whole load of initial conditions that are not findable a priori.
  - wizzwizz4 2y ago
    Physics is the study of reality under the assumption that it's lawful. The real world doesn't run on physics: it just is.
    - andrewflnr 2y ago
      Yes, that's one of the less mathematically optimistic perspectives. :)
    - mistermann 2y ago
      The physical portion of reality.
      - wizzwizz4 2y ago
        No, the causal portion of reality. (Philosophers of metaphysics are still arguing whether acausal aspects of reality are, in any real sense, real, but we don't need to listen to them.) If we discover something non-physical (the usual example being ghosts), that'll just become a new branch of physics. Physics currently talks about dark energy, the geometry of spacetime, and quantum superposition. I don't think you can get much less physical than that.
        mistermann 2y ago
        > No, the causal portion of reality. You are welcome to make an assertion that causal forces lie only in the physical realm, but declaring something to be true does not necessarily make it true, though at scale it can certainly make it seem true. See: https://en.wikipedia.org/wiki/Ideology https://en.wikipedia.org/wiki/Ideology >> An ideology is a set of beliefs or philosophies attributed to a person or group of persons, especially those held for reasons that are not purely epistemic... https://en.wikipedia.org/wiki/Illusory_truth_effect https://en.wikipedia.org/wiki/Illusory_truth_effect >> The illusory truth effect (also known as the illusion of truth effect, validity effect, truth effect, or the reiteration effect) is the tendency to believe false[1] information to be correct after repeated exposure. [1] The "false" designation here is unnecessary and flawed imho (or better: a fine example of how ubiquitous this problem is). > (Philosophers of metaphysics are still arguing whether acausal aspects of reality are, in any real sense, real, What meaning do you assign to the symbol "real" in this context? Is it flawless? > ...but we don't need to listen to them.) In an absolute sense, no you don't. But to achieve certain desires you may have to. Like the saying goes: "You may not be interested in metaphysics (or truth, etc), but it might be interested in you". But it's even more interesting: not only do you not have to listen to or seek truth, you can engage in mass collective story telling on the internet, confusing the population at scale. Don't believe me? There's a search function right here on HN, the evidence is there for the viewing! > If we discover something non-physical (the usual example being ghosts), that'll just become a new branch of physics. a) Science does like their Motte and Bailey. b) I doubt you can actually see the future. If you disagree, please explain, using only physics, how you can. > Physics currently talks about dark energy, the geometry of spacetime, and quantum superposition. I don't think you can get much less physical than that. Do you believe that aggregate reality is constrained by your cognitive abilities, or are you perhaps more so describing your opinion about "reality"?
        wizzwizz4 2y ago
        I don't think you understand what I'm saying. If we discover causal forces "outside the physical realm" (as we did when we first developed the theory of electromagnetism), we will simply redefine "the physical realm" to include the new, previously-unknown physics. (That, or we'll expand the domain of physics while preserving the legacy terminology, like when we decided that "world" meant a planet, or an "atom" could be separated into parts.) > What meaning do you assign to the symbol "real" in this context? Doesn't matter, because physics doesn't care whether or not its domain is "real". We can ignore the metaphysicians because physics is the study of models, observations, and discrepancies, and would work just as well if reality were an illusion. > I doubt you can actually see the future. If you disagree, please explain, using only physics, how you can. Information enters my brain. My brain gradually builds a predictive model, according to some (presumably physical) process that I call "me". I can then make confident conditional statements about the future, which historically have been overwhelmingly (though not exclusively) correct where the antecedent is satisfied. By induction, I infer that I possess the general ability to see the future with high accuracy, in certain domains. Though information theory is usually considered a branch of mathematics, the (incredibly eldritch) field of thermodynamics allows theorems of information theory to be translated into theorems of physics, and (in some cases) vice versa. > Do you believe that aggregate reality is constrained by your cognitive abilities, No, but again, that's irrelevant.
  - aatd86 2y ago
    Banach spaces looking like lightweight Euclidian spaces (in terms of constraints), and reality being experienced as data and applications, I'm going to try and say that: Physics is a subset of Mathematics but which subset we don't exactly know. In a sense, physics is the self-referential discovery of a subset of mathematics. Makes sense since "existence" is impredicative.
    - lanstin 2y ago
      I find infinite dimensional spaces even of zero curvature to be a bit creepy. Especially with a vector space structure, that just makes it worse.
    - andrewflnr 2y ago
      You're entirely missing the critical point of my comment, which is the initial conditions.
      - aatd86 2y ago
        I beg to differ. What are initial conditions if not some additional constraints?
    - smj-edison 2y ago
      Mathematics is perhaps a subset of logic? I'm not very familiar with this space, but I think it's pretty cool that so much of math can be represented with very simple rules building up, especially with things like the Lean proof language.
  - lanstin 2y ago
    My understanding is that QFT is not axiomatized - it works but there's a bit of hand-waving at the level of actual proofs. There are people working on this, but currently physics is physics and maths is maths.
    - SJC_Hacker 2y ago
      QFT also becomes increasingly unwieldy for large systems. E.g., try calculating bond energies of complex molecules. You can do it for hydrogen and "hydrogen like" molecules, but once you get beyond a few interactions, the differential equation does not have closed form solutions. This is not a total loss as you can resort to numerical solutions in at least some cases. Science is mostly about producing models that "work" whether this involves reductionism to more fundamental principles or not. At worst however, the model which describes the larger system should not conflict with the description of the smaller one.
      - lanstin 2y ago
        Verseon is doing raw quantum mechanics computations about various potential drugs and various important receptors. https://www.verseon.com/ https://www.verseon.com/
- jandrese 2y ago
  Physics is just applied math.
  - isk517 2y ago
    But not all math can be applied.
77pt77 2y ago
Physics is not math. Physics uses math.
aspenmayer 2y ago
Physics is not math any more than the map is the territory. https://en.wikipedia.org/wiki/Map%E2%80%93territory_relation https://en.wikipedia.org/wiki/Map%E2%80%93territory_relation
- baggy_trough 2y ago
  Depends on your philosophy.
  - aspenmayer 2y ago
    There are an uncountable number of atoms in the universe. There are nondeterministic occurrences in many natural processes. Even if the universe is a simulation, that doesn’t mean that it’s able to be represented or formalized from within the simulation. Math is possibly one of the best tools of the scientific method to make logical sense of the universe, but that doesn’t mean that we can compute any given thing due to the scales involved. Gödel was likely familiar with the unknowable nature of the universe given certain hard limits of calculation, computation, and measurement. Physics is the tool we use to move the world, yet we may never be able to build a lever or fulcrum long enough to actually do so - physics and math only give us a place to stand and means to orient ourselves. Everything else is engineering, I’d say. > Give me a place to stand and with a lever I will move the whole world. https://en.wikiquote.org/wiki/Archimedes https://en.wikiquote.org/wiki/Archimedes I would like to hear your thoughts, however. I think you’re right in a sense, that physics and math are possibly inseparable syntactically, similar to the identity property. If a thing is what it does, physics is math as much as it is logic, or vice versa. Like math, logic is what we understand it to be, regardless of correspondence to reality. Physics rather seeks to represent and model more than the abstract truths of math and logic, and physics has an element of necessary utility and correspondence to hypothetical or actually existing realities, possibilities, and observable phenomena, whereas math and logic are not burdened by testability, but are rather proven or disproven via internal consistency and formalisms. Like many tools, their proper usage comes down to holding them correctly, both in hand and in mind.
    - baggy_trough 2y ago

The chain reaction was still speculative. Also physics is math, but math is not physics.

by Isamu 2y ago

The chain reaction was still speculative. Also physics is math, but math is not physics.

genman 2y ago

Physics is math, but not all math is physics.

andrewflnr 2y ago
Physics is, optimistically, math plus a whole load of initial conditions that are not findable a priori.
- wizzwizz4 2y ago
  Physics is the study of reality under the assumption that it's lawful. The real world doesn't run on physics: it just is.
  - andrewflnr 2y ago
    Yes, that's one of the less mathematically optimistic perspectives. :)
  - mistermann 2y ago
    The physical portion of reality.
    - wizzwizz4 2y ago
      No, the causal portion of reality. (Philosophers of metaphysics are still arguing whether acausal aspects of reality are, in any real sense, real, but we don't need to listen to them.) If we discover something non-physical (the usual example being ghosts), that'll just become a new branch of physics. Physics currently talks about dark energy, the geometry of spacetime, and quantum superposition. I don't think you can get much less physical than that.
      - mistermann 2y ago
        > No, the causal portion of reality. You are welcome to make an assertion that causal forces lie only in the physical realm, but declaring something to be true does not necessarily make it true, though at scale it can certainly make it seem true. See: https://en.wikipedia.org/wiki/Ideology https://en.wikipedia.org/wiki/Ideology >> An ideology is a set of beliefs or philosophies attributed to a person or group of persons, especially those held for reasons that are not purely epistemic... https://en.wikipedia.org/wiki/Illusory_truth_effect https://en.wikipedia.org/wiki/Illusory_truth_effect >> The illusory truth effect (also known as the illusion of truth effect, validity effect, truth effect, or the reiteration effect) is the tendency to believe false[1] information to be correct after repeated exposure. [1] The "false" designation here is unnecessary and flawed imho (or better: a fine example of how ubiquitous this problem is). > (Philosophers of metaphysics are still arguing whether acausal aspects of reality are, in any real sense, real, What meaning do you assign to the symbol "real" in this context? Is it flawless? > ...but we don't need to listen to them.) In an absolute sense, no you don't. But to achieve certain desires you may have to. Like the saying goes: "You may not be interested in metaphysics (or truth, etc), but it might be interested in you". But it's even more interesting: not only do you not have to listen to or seek truth, you can engage in mass collective story telling on the internet, confusing the population at scale. Don't believe me? There's a search function right here on HN, the evidence is there for the viewing! > If we discover something non-physical (the usual example being ghosts), that'll just become a new branch of physics. a) Science does like their Motte and Bailey. b) I doubt you can actually see the future. If you disagree, please explain, using only physics, how you can. > Physics currently talks about dark energy, the geometry of spacetime, and quantum superposition. I don't think you can get much less physical than that. Do you believe that aggregate reality is constrained by your cognitive abilities, or are you perhaps more so describing your opinion about "reality"?
        wizzwizz4 2y ago
        I don't think you understand what I'm saying. If we discover causal forces "outside the physical realm" (as we did when we first developed the theory of electromagnetism), we will simply redefine "the physical realm" to include the new, previously-unknown physics. (That, or we'll expand the domain of physics while preserving the legacy terminology, like when we decided that "world" meant a planet, or an "atom" could be separated into parts.) > What meaning do you assign to the symbol "real" in this context? Doesn't matter, because physics doesn't care whether or not its domain is "real". We can ignore the metaphysicians because physics is the study of models, observations, and discrepancies, and would work just as well if reality were an illusion. > I doubt you can actually see the future. If you disagree, please explain, using only physics, how you can. Information enters my brain. My brain gradually builds a predictive model, according to some (presumably physical) process that I call "me". I can then make confident conditional statements about the future, which historically have been overwhelmingly (though not exclusively) correct where the antecedent is satisfied. By induction, I infer that I possess the general ability to see the future with high accuracy, in certain domains. Though information theory is usually considered a branch of mathematics, the (incredibly eldritch) field of thermodynamics allows theorems of information theory to be translated into theorems of physics, and (in some cases) vice versa. > Do you believe that aggregate reality is constrained by your cognitive abilities, No, but again, that's irrelevant.
- aatd86 2y ago
  Banach spaces looking like lightweight Euclidian spaces (in terms of constraints), and reality being experienced as data and applications, I'm going to try and say that: Physics is a subset of Mathematics but which subset we don't exactly know. In a sense, physics is the self-referential discovery of a subset of mathematics. Makes sense since "existence" is impredicative.
  - lanstin 2y ago
    I find infinite dimensional spaces even of zero curvature to be a bit creepy. Especially with a vector space structure, that just makes it worse.
  - andrewflnr 2y ago
    You're entirely missing the critical point of my comment, which is the initial conditions.
    - aatd86 2y ago
      I beg to differ. What are initial conditions if not some additional constraints?
  - smj-edison 2y ago
    Mathematics is perhaps a subset of logic? I'm not very familiar with this space, but I think it's pretty cool that so much of math can be represented with very simple rules building up, especially with things like the Lean proof language.
- lanstin 2y ago
  My understanding is that QFT is not axiomatized - it works but there's a bit of hand-waving at the level of actual proofs. There are people working on this, but currently physics is physics and maths is maths.
  - SJC_Hacker 2y ago
    QFT also becomes increasingly unwieldy for large systems. E.g., try calculating bond energies of complex molecules. You can do it for hydrogen and "hydrogen like" molecules, but once you get beyond a few interactions, the differential equation does not have closed form solutions. This is not a total loss as you can resort to numerical solutions in at least some cases. Science is mostly about producing models that "work" whether this involves reductionism to more fundamental principles or not. At worst however, the model which describes the larger system should not conflict with the description of the smaller one.
    - lanstin 2y ago
      Verseon is doing raw quantum mechanics computations about various potential drugs and various important receptors. https://www.verseon.com/ https://www.verseon.com/
jandrese 2y ago
Physics is just applied math.
- isk517 2y ago
  But not all math can be applied.

77pt77 2y ago

Physics is not math. Physics uses math.

aspenmayer 2y ago

Physics is not math any more than the map is the territory. https://en.wikipedia.org/wiki/Map%E2%80%93territory_relation https://en.wikipedia.org/wiki/Map%E2%80%93territory_relation

baggy_trough 2y ago
Depends on your philosophy.
- aspenmayer 2y ago
  There are an uncountable number of atoms in the universe. There are nondeterministic occurrences in many natural processes. Even if the universe is a simulation, that doesn’t mean that it’s able to be represented or formalized from within the simulation. Math is possibly one of the best tools of the scientific method to make logical sense of the universe, but that doesn’t mean that we can compute any given thing due to the scales involved. Gödel was likely familiar with the unknowable nature of the universe given certain hard limits of calculation, computation, and measurement. Physics is the tool we use to move the world, yet we may never be able to build a lever or fulcrum long enough to actually do so - physics and math only give us a place to stand and means to orient ourselves. Everything else is engineering, I’d say. > Give me a place to stand and with a lever I will move the whole world. https://en.wikiquote.org/wiki/Archimedes https://en.wikiquote.org/wiki/Archimedes I would like to hear your thoughts, however. I think you’re right in a sense, that physics and math are possibly inseparable syntactically, similar to the identity property. If a thing is what it does, physics is math as much as it is logic, or vice versa. Like math, logic is what we understand it to be, regardless of correspondence to reality. Physics rather seeks to represent and model more than the abstract truths of math and logic, and physics has an element of necessary utility and correspondence to hypothetical or actually existing realities, possibilities, and observable phenomena, whereas math and logic are not burdened by testability, but are rather proven or disproven via internal consistency and formalisms. Like many tools, their proper usage comes down to holding them correctly, both in hand and in mind.
  - baggy_trough 2y ago