5 ms·
Physics is math, but not all math is physics.
by genman 2y ago
Physics is math, but not all math is physics.
- andrewflnr 2y agoPhysics is, optimistically, math plus a whole load of initial conditions that are not findable a priori.
- wizzwizz4 2y agoPhysics 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 agoYes, that's one of the less mathematically optimistic perspectives. :)
- mistermann 2y agoThe physical portion of reality.
- wizzwizz4 2y agoNo, 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 agoI 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.
- mistermann 2y ago> I don't think you understand what I'm saying. You are telling stories. Stories are the foundation of the culture you have been raised in, they trump everything. I know you don't understand what I'm saying.
- aatd86 2y agoBanach 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 agoI 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 agoYou're entirely missing the critical point of my comment, which is the initial conditions.
- aatd86 2y agoI beg to differ. What are initial conditions if not some additional constraints?
- smj-edison 2y agoMathematics 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 agoMy 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 agoQFT 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 agoVerseon is doing raw quantum mechanics computations about various potential drugs and various important receptors. https://www.verseon.com/ https://www.verseon.com/
- jandrese 2y agoPhysics is just applied math.
- isk517 2y agoBut not all math can be applied.