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There is no room for free will in physics, period. All processes are completely deterministic. Even quantum processes might appear to be probabilistic if you lo

There is no room for free will in physics, period. All processes are completely deterministic. Even quantum processes might appear to be probabilistic if you look at individual particles, but the statistics are nevertheless completely deterministic: if you look at enough particles, a predictable shape will emerge. The future is set in stone and not only is there no way to change it, but the concept of changing the future doesn't even make sense. Free will is not something that exists in nature, it is something that exists in the psychology of agents with limited information about the world they operate in. Attempting to find a physical basis for free will is like trying to use an optical drive to read data off a pancake.

time_to_smile 5y ago
You can even leave out the 'physics' part there. "Free will" is a very poorly defined concept that mostly falls out of problems with theodicy in early moral philosophy. Since the idea of "free will" plays a major role in Christian ethics this notion has permeated a huge amount of the Western intellectual tradition, but only makes sense in the framework of other archaic philosophical questions around theodicy like "if god is omnipotent, omniscient, and omnibenevolent why is there evil?" This question is only remotely interesting if you have a cultural reason to need to believe that these three things must be true (or if you're curious about the development of the Western intellectual tradition, in which case it's a very important question to understand).
- whatshisface 5y ago
  Free will might be hard to define but it has plenty of very well-defined corollaries. For example, if there is such a thing as free will, it would not be possible to reliably predict a human being's actions in advance.
  - time_to_smile 5y ago
    > not be possible to reliably predict a human being's actions in advance. That's also true for purely deterministic systems. Basically any complex deterministic system (and quite a few relatively simple ones) you very quickly get to a point where you can't predict future behavior. On top of that, showing exactly the issues with metaphysical "free will", this corollary has a lot of constraints that are also poorly defined. For example if a person's behavior were entirely unpredictable (i.e. completely random) we would also say that they don't have free will. Therefore there is only a subset of unpredictable behaviors we would say follow from free will but that subset is just as tricky to pin down as the notion of free will itself. "Free will" only makes sense in a particular moral world view with plenty of axioms most people would agree don't hold for them. It's also worth clarifying that "free will" only becomes problematic to define in when it is posed as a metaphysical issue. We clearly have very useful, practical definitions of free will such as not holding people accountable for doing something when held at gun point.
    - whatshisface 5y ago
      The difference between quickly getting to a point where you can't forecast the weather, and the fact that you can't predict wavefunction collapse at all, is significant on a more than metaphysical level. Figuring out which bucket human beings fall in to is a legitimate question.
      - time_to_smile 5y ago
        > the weather > wavefunction Which of these are commonly accepted (or even argued by a sizable minority) to have free will in a metaphysical sense? > Figuring out which bucket human beings fall in to is a legitimate question. That may be true, but it doesn't seem like it has anything to do with the ill-defined notion of "free will". I'm also not familiar with anyone who views human behavior to be anything like a collapsing wave form so I'm not entirely sure this is a "legitimate" question since I'm not sure there is any evidence or support for the one side of the argument (though I'm always up for pointers to arguments about this).
        whatshisface 5y ago
        >Which of these are commonly accepted (or even argued by a sizable minority) to have free will in a metaphysical sense? Of the two that would be the wave functions, some of which are people, and people are what's argued to have free will. >That may be true, but it doesn't seem like it has anything to do with the ill-defined notion of "free will". Nondeterminism in physics is the space that free will is allowed to fill, and if there was none, there would be no room for free will. >I'm also not familiar with anyone who views human behavior to be anything like a collapsing wave form Human beings are physical systems, quite chaotic at that. It is possible that deep inside your brain, decisions turn on molecular events that are uncertain due to quantum mechanics. Evidence for free will? Not really, but it's a hole in determinism that makes false the statement, "physics leaves no room for free will."
        gfody 5y ago
        > Which of these are commonly accepted (or even argued by a sizable minority) to have free will in a metaphysical sense? both, see the free will theorem from Conway and Kochen
whatshisface 5y ago
There is no room for free will in classical mechanics. Quantum mechanics has plenty of "room for free will," because either: 1. The universe is not deterministic (if you believe that wavefunctions collapse) 2. The mysterious thing that makes conscious entities experience high-amplitude events more often than low-amplitude events is not deterministic (if you believe in MWI). Evidence for free will, a definition of free will; those things physics cannot provide. But there's room for it.
- kelseyfrog 5y ago
  There are more than just those two interpretations. Super determinism, for example https://en.m.wikipedia.org/wiki/Superdeterminism https://en.m.wikipedia.org/wiki/Superdeterminism
arbitrage 5y ago
> quantum processes [...] are nevertheless completely deterministic It's like you're trying to avoid mentioning hidden variables or bell's theorem directly. That is, you're probably not correct when you say something like that.
rthomas6 5y ago
Two objections: 1. Chaos theory ensures that unless we have INFINITE precision measurements, even a perfect simulation of our universe will diverge based on even the smallest differences. A difference of one particle's velocity in the googolth decimal place will eventually cause wildly different simulation outcomes. So, in practice, it's impossible to know what's going to happen given a long enough time frame, unless we can get advanced enough to have literally infinite precision measurements. 2. Given objection 1, using the law of large numbers to explain away quantum processes' non-determinism from initial conditions seems like a cop-out to me. Yes, given enough particles, they converge around some predictable value. But given the need to have exactness in measurements to predict chaotic processes, if a SMALL number of individual particles interact with other matter, and they sometimes do, how could the probabilistic nature of those individual particles be neglected? Let me sum it up this way. If I take a quantum random number generator and use it to generate lat-long coordinates, and visit that place, could anyone or anything predict what happens given initial conditions before I do that? No, it is not bound by initial conditions.
feoren 5y ago
Quite the opposite: physics is predicated on the idea of free will in the experimenter. That is: their decision to use X machine to perform Y experiment at Z time is essentially an independent, or at least fully random, "choice" on their part. If the experimenter does not have free will, then you run into the possibility of their decision to run the experiment as being somehow entangled with the results. See "Superdeterminism" https://en.wikipedia.org/wiki/Superdeterminism https://en.wikipedia.org/wiki/Superdeterminism But otherwise I agree that "free will" is basically just a silly argument over the definition of an undefinable term, or a way to explain away loopholes in theology.

time_to_smile 5y ago

You can even leave out the 'physics' part there. "Free will" is a very poorly defined concept that mostly falls out of problems with theodicy in early moral philosophy. Since the idea of "free will" plays a major role in Christian ethics this notion has permeated a huge amount of the Western intellectual tradition, but only makes sense in the framework of other archaic philosophical questions around theodicy like "if god is omnipotent, omniscient, and omnibenevolent why is there evil?" This question is only remotely interesting if you have a cultural reason to need to believe that these three things must be true (or if you're curious about the development of the Western intellectual tradition, in which case it's a very important question to understand).

whatshisface 5y ago
Free will might be hard to define but it has plenty of very well-defined corollaries. For example, if there is such a thing as free will, it would not be possible to reliably predict a human being's actions in advance.
- time_to_smile 5y ago
  > not be possible to reliably predict a human being's actions in advance. That's also true for purely deterministic systems. Basically any complex deterministic system (and quite a few relatively simple ones) you very quickly get to a point where you can't predict future behavior. On top of that, showing exactly the issues with metaphysical "free will", this corollary has a lot of constraints that are also poorly defined. For example if a person's behavior were entirely unpredictable (i.e. completely random) we would also say that they don't have free will. Therefore there is only a subset of unpredictable behaviors we would say follow from free will but that subset is just as tricky to pin down as the notion of free will itself. "Free will" only makes sense in a particular moral world view with plenty of axioms most people would agree don't hold for them. It's also worth clarifying that "free will" only becomes problematic to define in when it is posed as a metaphysical issue. We clearly have very useful, practical definitions of free will such as not holding people accountable for doing something when held at gun point.
  - whatshisface 5y ago
    The difference between quickly getting to a point where you can't forecast the weather, and the fact that you can't predict wavefunction collapse at all, is significant on a more than metaphysical level. Figuring out which bucket human beings fall in to is a legitimate question.
    - time_to_smile 5y ago
      > the weather > wavefunction Which of these are commonly accepted (or even argued by a sizable minority) to have free will in a metaphysical sense? > Figuring out which bucket human beings fall in to is a legitimate question. That may be true, but it doesn't seem like it has anything to do with the ill-defined notion of "free will". I'm also not familiar with anyone who views human behavior to be anything like a collapsing wave form so I'm not entirely sure this is a "legitimate" question since I'm not sure there is any evidence or support for the one side of the argument (though I'm always up for pointers to arguments about this).
      - whatshisface 5y ago
        >Which of these are commonly accepted (or even argued by a sizable minority) to have free will in a metaphysical sense? Of the two that would be the wave functions, some of which are people, and people are what's argued to have free will. >That may be true, but it doesn't seem like it has anything to do with the ill-defined notion of "free will". Nondeterminism in physics is the space that free will is allowed to fill, and if there was none, there would be no room for free will. >I'm also not familiar with anyone who views human behavior to be anything like a collapsing wave form Human beings are physical systems, quite chaotic at that. It is possible that deep inside your brain, decisions turn on molecular events that are uncertain due to quantum mechanics. Evidence for free will? Not really, but it's a hole in determinism that makes false the statement, "physics leaves no room for free will."
      - gfody 5y ago
        > Which of these are commonly accepted (or even argued by a sizable minority) to have free will in a metaphysical sense? both, see the free will theorem from Conway and Kochen

whatshisface 5y ago

There is no room for free will in classical mechanics. Quantum mechanics has plenty of "room for free will," because either: 1. The universe is not deterministic (if you believe that wavefunctions collapse) 2. The mysterious thing that makes conscious entities experience high-amplitude events more often than low-amplitude events is not deterministic (if you believe in MWI). Evidence for free will, a definition of free will; those things physics cannot provide. But there's room for it.

kelseyfrog 5y ago
There are more than just those two interpretations. Super determinism, for example https://en.m.wikipedia.org/wiki/Superdeterminism https://en.m.wikipedia.org/wiki/Superdeterminism

arbitrage 5y ago

> quantum processes [...] are nevertheless completely deterministic It's like you're trying to avoid mentioning hidden variables or bell's theorem directly. That is, you're probably not correct when you say something like that.

rthomas6 5y ago

Two objections: 1. Chaos theory ensures that unless we have INFINITE precision measurements, even a perfect simulation of our universe will diverge based on even the smallest differences. A difference of one particle's velocity in the googolth decimal place will eventually cause wildly different simulation outcomes. So, in practice, it's impossible to know what's going to happen given a long enough time frame, unless we can get advanced enough to have literally infinite precision measurements. 2. Given objection 1, using the law of large numbers to explain away quantum processes' non-determinism from initial conditions seems like a cop-out to me. Yes, given enough particles, they converge around some predictable value. But given the need to have exactness in measurements to predict chaotic processes, if a SMALL number of individual particles interact with other matter, and they sometimes do, how could the probabilistic nature of those individual particles be neglected? Let me sum it up this way. If I take a quantum random number generator and use it to generate lat-long coordinates, and visit that place, could anyone or anything predict what happens given initial conditions before I do that? No, it is not bound by initial conditions.

feoren 5y ago

Quite the opposite: physics is predicated on the idea of free will in the experimenter. That is: their decision to use X machine to perform Y experiment at Z time is essentially an independent, or at least fully random, "choice" on their part. If the experimenter does not have free will, then you run into the possibility of their decision to run the experiment as being somehow entangled with the results. See "Superdeterminism" https://en.wikipedia.org/wiki/Superdeterminism https://en.wikipedia.org/wiki/Superdeterminism But otherwise I agree that "free will" is basically just a silly argument over the definition of an undefinable term, or a way to explain away loopholes in theology.