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And what could it mean for the concept of free-will?

Rose wrote:I've read about this before, and from what I can recall,

And what could it mean for the concept of free-will?

Determinism and free will are basically opposites. They can't coexist. However, that's just my (tentative) conclusion, and I'd love to hear counterpoints.

Seneschal wrote:

Rose wrote:I've read about this before, and from what I can recall,

And what could it mean for the concept of free-will?

Determinism and free will are basically opposites. They can't coexist. However, that's just my (tentative) conclusion, and I'd love to hear counterpoints.

http://en.wikipedia.org/wiki/Compatibilism

Rose wrote:So, I think the biggest question is, what exactly is "free will"?

Nostromo wrote:I was under the impression that quantum physics essentially disproved determinism -- that there's an inherent amount of randomness present in the universe, at a subatomic level.

T̷s͢uk̕a͡t͜ư wrote:

Nostromo wrote:I was under the impression that quantum physics essentially disproved determinism -- that there's an inherent amount of randomness present in the universe, at a subatomic level.

scythe will be able to kick my ass if I'm wrong about this, but...
Yeah, as I understand it, things aren't so deterministic at the quantum scale. However, once you approach any appreciable scale (e.g. the size of a nucleon), probabilities that matter will act in the ways non-quantum-scale physics would predict are so close to 100% that they may as well be 100%. Note that neurons, relative to these scales, are fucking huge, and therefore I posit that humans will act deterministically (lim_{n -> 100} n)% of the time.

T̷s͢uk̕a͡t͜ư wrote:and therefore I posit that humans will act deterministically (lim_{n -> 100} n)% of the time.
But I will also happily concede that because we are not aware of all the details which influence how reality will behave exactly, we have the illusion of free will, which is functionally equivalent to actual free will in the realm of human experience.

ENT474 wrote:Schrodinger's cat could disprove that...

T̷s͢uk̕a͡t͜ư wrote:

ENT474 wrote:Schrodinger's cat could disprove that...

No, don't dot-dot-dot. Go ahead and explain yourself.

The point of the Schrodinger's cat experiment is to highlight and even poke fun at the measurement problem in quantum mechanics. The 'boundary' between the classical and quantum world where wavefunction collapse occurs is not very well defined in textbook quantum mechanics.

When you set up a reasonable experiment, it is usually quite obvious when and how the wavefunctions collapse - when something hits the detector! How the wavefunction collapses is also obvious - in such a way as to either trigger or not trigger a detector reading.

So QM is great for predicting the outcome most experiments - which is really the job of a physical model of the universe, but philosophically it is deeply unsatisfying. We don't get a clear picture of how the universe functions. The only thing that anyone can do is to set up a hypothetical experiment, and then let common sense dictate what constitutes a detector and how and when the wavefunction should collapse. But how is this process of collapse actually happening microscopically, every moment, in every part of the universe? This is an open question that is only currently getting some of the attention that it deserves.

In the case of the cat, a cat is clearly a classical object. No experiment has ever seen interference between different states of a cat in superposition - the idea is absurd. So the cat is a detector - or even better, the poison gas trap, also a classical object, is a detector. It either fires or it doesn't, and the microscopic system of the decaying nucleus collapses.
Ultimately, every 'classical' object is ultimately comprised of billions of quantum objects - atoms, and so one should ask how is this collapse transition happening. To probe this, one needs to perform experiments to look more closely at objects that are not obviously classical, like a cat, or obviously quantum, like an atom. What about a ball of 200 atoms - a quantum dot? How about a vibrating bridge made of a few thousand atoms cooled to microKelvin temperatures? These experiments are beginning to be performed.

My guess is that the process of collapse will be one day properly understood in the statistical mechanics of the 'classical object' which is really a huge quantum system of a myriad of particles.

Duchess of Awesome wrote:This may be the trap that Suki is trying to get you to fall into but I'm going to trigger it now anyway.

Schrödinger's cat is probably the single most misunderstood aspect of quantum mechanics. It isn't meant to be, in any way, a proof of "the intrusion of quantum physics into the real world". Exactly the opposite, it's meant to criticize the way that the Copenhagen interpretation of quantum mechanics is (or isn't, more accurately) applied to everyday objects. Rather than bumbling through my own explanation, I'll borrow from the words of an expert in relativistic nuclear collisions.

The point of the Schrodinger's cat experiment is to highlight and even poke fun at the measurement problem in quantum mechanics. The 'boundary' between the classical and quantum world where wavefunction collapse occurs is not very well defined in textbook quantum mechanics.

When you set up a reasonable experiment, it is usually quite obvious when and how the wavefunctions collapse - when something hits the detector! How the wavefunction collapses is also obvious - in such a way as to either trigger or not trigger a detector reading.

So QM is great for predicting the outcome most experiments - which is really the job of a physical model of the universe, but philosophically it is deeply unsatisfying. We don't get a clear picture of how the universe functions. The only thing that anyone can do is to set up a hypothetical experiment, and then let common sense dictate what constitutes a detector and how and when the wavefunction should collapse. But how is this process of collapse actually happening microscopically, every moment, in every part of the universe? This is an open question that is only currently getting some of the attention that it deserves.

In the case of the cat, a cat is clearly a classical object. No experiment has ever seen interference between different states of a cat in superposition - the idea is absurd. So the cat is a detector - or even better, the poison gas trap, also a classical object, is a detector. It either fires or it doesn't, and the microscopic system of the decaying nucleus collapses.
Ultimately, every 'classical' object is ultimately comprised of billions of quantum objects - atoms, and so one should ask how is this collapse transition happening. To probe this, one needs to perform experiments to look more closely at objects that are not obviously classical, like a cat, or obviously quantum, like an atom. What about a ball of 200 atoms - a quantum dot? How about a vibrating bridge made of a few thousand atoms cooled to microKelvin temperatures? These experiments are beginning to be performed.

My guess is that the process of collapse will be one day properly understood in the statistical mechanics of the 'classical object' which is really a huge quantum system of a myriad of particles.