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I was trained as a physicist and I love physics, but I believe it is a genuinely open question whether all these laws, which probably do encompass physics per s

I was trained as a physicist and I love physics, but I believe it is a genuinely open question whether all these laws, which probably do encompass physics per se as we know it, actually therefor encompass the whole world. If you genuinely believe in emergent phenomena, then these laws genuinely do not describe all the things that happen in the universe. I do not believe in emergence in this form, but some philosophers of science do.

kosievdmerwe 3y ago
How do you mean emergent phenomena? Like with gliders and stuff in Conway's game of life? Where the rules of the game are trivial, but the higher level behavior is not. That said, if that's what you mean, then it's been my belief for a long time that if we were given a book with all the true laws of physics at the lowest level we would still need to spend centuries deriving useful approximations for our practical concerns at the larger scales.
- hgsgm 3y ago
  It's a pretty standard belief. We've spent centuries as a species investigating the consequences of simple approcimate rules like F=ma.
- nathan_compton 3y ago
  Well, consider the art installation called Descension by Anish Kapoor[1]. The vortex which makes up the piece emerges from the constraints imposed upon the fluid by the artist. If we replaced the water in the installation with any fluid with similar viscosity, the vortex would remain. Thus it appears to be the case that the vortex does _not_ supervene upon the actual substances which makes it up per se. In the case of Descension the constraints are somewhat artificial and imposed by the artist. Arguably, the phenomena supervenes upon the physical structure of those constraints. But consider some living organism. It's various physical parts might be replaced by other parts with similar properties (with respect to their function) and the organism would keep existing as itself. But there isn't any particular substance which maintains the constraints which define the organism. Some philosophers of science (eg Terrance Deacon) uphold that this means emergent phenomenon do not supervene upon their material constituents per se, and are thus not determined by the laws of physics which dictate their properties. I don't buy it, but it is a position. [1] https://www.thisiscolossal.com/2015/02/anish-kapoor-decension-vortex/ https://www.thisiscolossal.com/2015/02/anish-kapoor-decensio...
  - kosievdmerwe 3y ago
    Interesting. I definitely don't agree with that myself. It sort of reminds me of the Philosophy of Mathematics[1], where there are some schools of thought that I consider vaguely ridiculous too. Like some schools of Platonism suggesting mathematical objects actually exist somehow instead of it just being a convenient linguistic shorthand. [1] https://en.wikipedia.org/wiki/Philosophy_of_mathematics https://en.wikipedia.org/wiki/Philosophy_of_mathematics
karaterobot 3y ago
My best friend growing up was always into physics, and at one point in high school I remember him committing to a deterministic view of the world, because everything could be described by physics, and if you knew the position and velocity of every particle in the universe, you could fast forward or rewind everything, and so on. After he got his Ph.D. we were talking about similar topics, and I asked him if he still believed that. He blinked a couple times and said, "absolutely not, it's much more complicated," which I have to admit I was glad to hear him say. But what I ought to have asked is whether he thinks it's because the rules we know are incorrect or missing a few key features, or whether at some fundamental level they just can't do what he used to think they did. To my worldview, it borders on magical thinking to believe they couldn't describe everything in the universe. On the other hand, intuitively, it seems deeply unsatisfying (not to mention empirically unproven) to claim they do. It's a big question for sure.
- venv 3y ago
  In our current understanding of the world (quantum mechanics), the world is inherently probabilistic ("random", not deterministic) in the microscopic realm. There are differing opinions among physicists whether or not there could be a more fundamental layer of reality beyond this, and if so, whether it would be deterministic. Notably it could be said the mainstream view is that reality is not deterministic.
  - goatlover 3y ago
    The second most popular view is that the universe branches deterministically, which means there will be some observers in a very small percentage of branches who observe seemingly miraculous events (very low probability). Their notion of probability would be different from ours.
  - RetroTechie 3y ago
    If you were shown a screen, told it consists of individual pixels, but no matter what microscope you grab you can't discern those pixels, does that screen consist of pixels or is it a continuous canvas? That's kind of where physics is at, no? Until you succeed in building an apparatus that lets you see individual pixels, it's a continuous canvas for all intents & purposes. Some discrete & deterministic layer underneath it all is a more elegant possibility imho. Might suit people who prefer "nature at its deepest level is math" worldview. But why would reality 'bother' to fit into that shoe? It just is. Whatever that is. Discrete or continuous, deterministic or probabilistic.

kosievdmerwe 3y ago

How do you mean emergent phenomena? Like with gliders and stuff in Conway's game of life? Where the rules of the game are trivial, but the higher level behavior is not. That said, if that's what you mean, then it's been my belief for a long time that if we were given a book with all the true laws of physics at the lowest level we would still need to spend centuries deriving useful approximations for our practical concerns at the larger scales.

hgsgm 3y ago
It's a pretty standard belief. We've spent centuries as a species investigating the consequences of simple approcimate rules like F=ma.
nathan_compton 3y ago
Well, consider the art installation called Descension by Anish Kapoor[1]. The vortex which makes up the piece emerges from the constraints imposed upon the fluid by the artist. If we replaced the water in the installation with any fluid with similar viscosity, the vortex would remain. Thus it appears to be the case that the vortex does _not_ supervene upon the actual substances which makes it up per se. In the case of Descension the constraints are somewhat artificial and imposed by the artist. Arguably, the phenomena supervenes upon the physical structure of those constraints. But consider some living organism. It's various physical parts might be replaced by other parts with similar properties (with respect to their function) and the organism would keep existing as itself. But there isn't any particular substance which maintains the constraints which define the organism. Some philosophers of science (eg Terrance Deacon) uphold that this means emergent phenomenon do not supervene upon their material constituents per se, and are thus not determined by the laws of physics which dictate their properties. I don't buy it, but it is a position. [1] https://www.thisiscolossal.com/2015/02/anish-kapoor-decension-vortex/ https://www.thisiscolossal.com/2015/02/anish-kapoor-decensio...
- kosievdmerwe 3y ago
  Interesting. I definitely don't agree with that myself. It sort of reminds me of the Philosophy of Mathematics[1], where there are some schools of thought that I consider vaguely ridiculous too. Like some schools of Platonism suggesting mathematical objects actually exist somehow instead of it just being a convenient linguistic shorthand. [1] https://en.wikipedia.org/wiki/Philosophy_of_mathematics https://en.wikipedia.org/wiki/Philosophy_of_mathematics

karaterobot 3y ago

My best friend growing up was always into physics, and at one point in high school I remember him committing to a deterministic view of the world, because everything could be described by physics, and if you knew the position and velocity of every particle in the universe, you could fast forward or rewind everything, and so on. After he got his Ph.D. we were talking about similar topics, and I asked him if he still believed that. He blinked a couple times and said, "absolutely not, it's much more complicated," which I have to admit I was glad to hear him say. But what I ought to have asked is whether he thinks it's because the rules we know are incorrect or missing a few key features, or whether at some fundamental level they just can't do what he used to think they did. To my worldview, it borders on magical thinking to believe they couldn't describe everything in the universe. On the other hand, intuitively, it seems deeply unsatisfying (not to mention empirically unproven) to claim they do. It's a big question for sure.

venv 3y ago
In our current understanding of the world (quantum mechanics), the world is inherently probabilistic ("random", not deterministic) in the microscopic realm. There are differing opinions among physicists whether or not there could be a more fundamental layer of reality beyond this, and if so, whether it would be deterministic. Notably it could be said the mainstream view is that reality is not deterministic.
- goatlover 3y ago
  The second most popular view is that the universe branches deterministically, which means there will be some observers in a very small percentage of branches who observe seemingly miraculous events (very low probability). Their notion of probability would be different from ours.
- RetroTechie 3y ago
  If you were shown a screen, told it consists of individual pixels, but no matter what microscope you grab you can't discern those pixels, does that screen consist of pixels or is it a continuous canvas? That's kind of where physics is at, no? Until you succeed in building an apparatus that lets you see individual pixels, it's a continuous canvas for all intents & purposes. Some discrete & deterministic layer underneath it all is a more elegant possibility imho. Might suit people who prefer "nature at its deepest level is math" worldview. But why would reality 'bother' to fit into that shoe? It just is. Whatever that is. Discrete or continuous, deterministic or probabilistic.