Does determinism really pose a problem for free will?
- Consul
- Posts: 6038
- Joined: February 21st, 2014, 6:32 am
- Location: Germany
Re: Does determinism really pose a problem for free will?
"There's an entirely different way of trying to understand all this stuff (a way of being absolutely deviant about it, a way of being polymorphously heretical against the standard way of thinking, away of tearing quantum mechanics all the way down and replacing it with something else) which was first hinted at a long time ago by Louis de Broglie (1930), and which was first developed into a genuine mathematical theory back in the fifties by David Bohm (1952), and which has recently been put into a particularly clear and simple and powerful form by John Bell (1982), and that's what this chapter is going to be about.
Bohm's theory has more or less (but not exactly) the same empirical content as quantum mechanics does, and it has much of the same mathematical formalism as quantum mechanics does too, but the metaphysics is different.
The metaphysics of this theory is exactly the same as the metaphysics of classical mechanics.
Here's what I mean:
This theory presumes (to begin with) that every material particle in the world invariably has a perfectly determinate position. And what this theory is about is the evolution of those positions in time. What this theory takes the job of physical science to be (to put it another way) is nothing other than to produce an account of those evolutions; and the various nonparticulate sorts of physical things that come up in this theory (things like force fields, for example, and other sorts of things too, of which we'll speak presently) come up (just as they do in classical mechanics) only to the extent that we find we need to bring them up in order to produce the account of the particle motions.
And it turns out that the account which Bohm's theory gives of those motions is completely deterministic. And so, on Bohm's theory, the world can only appear to us to evolve probabilistically (and of course it does appear that way to us) in the event that we are somehow ignorant of its exact state. And so the very idea of probability will have to enter into this theory as some kind of an epistemic idea, just as it enters into classical statistical mechanics.
What the physical world consists of besides particles and besides force fields, on this theory, is (oddly) wave functions. That's what the theory requires in order to produce its account of the particle motions. The quantum-mechanical wave functions are conceived of in this theory as genuinely physical things, as something somewhat like force fields (but not quite), and anyway as something quite distinct from the particles; and the laws of the evolutions of these wave functions are stipulated to be precisely the linear quantum-mechanical equations of motion (always, period; wave functions never collapse on this theory); and the job of these wave functions in this theory is to sort of push the particles around (as force fields do), to guide them along their proper courses; and there are additional laws in the theory (new ones, un-quantum-mechanical ones) which stipulate precisely how they do that.
([Note 2]: Perhaps all this is worth spelling out in somewhat more pedantic detail. Here's the idea:
What quantum mechanics takes the wave function of a particle to be is merely a certain sort of mathematical representation of that particle's state.
What this theory takes the wave function of a particle to be, on the other hand, is a certain sort of genuinely physical stuff.
And the physical properties of such wave-functions-considered-as-stuff are (as with force fields) their amplitudes at every point in space.
And those amplitudes will invariably have determinate values (just as they invariably do, as purely mathematical objects, in quantum mechanics).)"
(Albert, David Z. Quantum Mechanics and Experience. Cambridge, MA: Harvard University Press, 1992. pp. 134-5)
- Consul
- Posts: 6038
- Joined: February 21st, 2014, 6:32 am
- Location: Germany
Re: Does determinism really pose a problem for free will?
"In Bohmian mechanics, everything is pre-established as in classical physics: in order to achieve this, one is obliged to postulate the existence of an all-pervasive 'quantum potential', a sort of wave that carries no energy and has to change instantaneously everywhere when a measurement is made – this is a strongly non-local hidden variable, the non-locality being needed to justify the violation of Bell's inequality and similar phenomena. In Bohmian mechanics, measurement is not a problem because everything is deterministic."Consul wrote: ↑June 26th, 2019, 4:41 pmIt should be mentioned that there is a completely deterministic interpretation of QM—Bohmian Mechanics—according to which indeterminacy isn't an ontological phenomenon (out there in physical reality) but merely an epistemological one.
(Scarani, Valerio, Chua Lynn, and Liu Shi Yang. Six Quantum Pieces: A First Course in Quantum Physics. London: World Scientific Publishing, 2010. p. 104)
"It is widely believed that quantum mechanics is starkly opposed to classical physics, because quantum mechanics claims that the world is governed by fundamentally indeterministic laws. As it happens, this common belief oversimplifies somewhat. Quantum mechanics is a theory that is formulated in relatively mathematical terms, quite removed from concepts of directly observable physical entities. Consequently, there is a great deal of room for interpretation of the meaning of the mathematics. Indeed, there are at least three interpretations of quantum mechanics which are serious candidates for giving an adequate account of how the mathematics relates to reality.
Of these three interpretations, one of them – Bohmian mechanics – is completely deterministic. The other two interpretations each involve probability, but in rather different ways. So there is no straightforward answer to the question, ‘What is the role of probability in quantum mechanics?’"
(Handfield, Toby. A Philosophical Guide to Chance. Cambridge: Cambridge University Press, 2012. p. 146)
A good video for laypersons ("Pilot Wave Theory" is just another name for Bohmian Mechanics):
Another good, more informative one:
- detail
- Posts: 171
- Joined: June 1st, 2019, 1:39 pm
Re: Does determinism really pose a problem for free will?
This is exactly a philosphical standpoint. You argue what humans don't measure is not existent. If the dynamics of the quantum mechanical world would be real , then there is no difference if a human takes a measurement or not. You add to determinism another philosophical standpoint, existentialism or materialism to discuss this and then end up with a statement of physics ?
You either demand that matter behaves like this no matter if humans do exist or not or you demand that just because humans exist matter has to behave like this because we measured the scenario. Is science not like plato's cave example, that we just see the projection of a universe that could have worked with out us ? But as you may have remarked you added to determinism another standpoint either existentialism or materialism.
- detail
- Posts: 171
- Joined: June 1st, 2019, 1:39 pm
Re: Does determinism really pose a problem for free will?
The measuring axiom of classical quantum mechanics , brings together with the measurment true stochastics into play. But there are some
people who do adiabatic pertubation theory of quantum mechanics , that try to introduce measurement in varied way. If quantum mechanics would be the model per se to describe the universe,we would know if a hamiltonian of the whole universe would exist then all measurements would be included. So an experiment from outside of the system would not be possible. But then the universe would evolve in a deterministic way after the schrödinger equation. If not true stochastics does exist , and this would be the end for determinism. But we don't know even for the prevously done remarks about the ongoing situation in physics.
-
- Moderator
- Posts: 6105
- Joined: September 11th, 2016, 2:11 pm
Re: Does determinism really pose a problem for free will?
If so our understanding of determinism is deficient and the problem of determinism is an epistemological problem.
Determinism does not of course imply nothing but causal chains. Determinism implies reality as integrated whole.
(my comment on David Bohm 'Wholeness and the Implicate Order'.)
- LuckyR
- Moderator
- Posts: 7935
- Joined: January 18th, 2015, 1:16 am
Re: Does determinism really pose a problem for free will?
True, I suppose, but if we live in a noncausal, yet deterministic universe, it will behave to an observer as if there is free will.Belindi wrote: ↑June 27th, 2019, 5:47 am Does 'determinism'always imply causal determinism? Or is there order which is not causal order?
If so our understanding of determinism is deficient and the problem of determinism is an epistemological problem.
Determinism does not of course imply nothing but causal chains. Determinism implies reality as integrated whole.
(my comment on David Bohm 'Wholeness and the Implicate Order'.)
- Felix
- Posts: 3117
- Joined: February 9th, 2009, 5:45 am
Re: Does determinism really pose a problem for free will?
Seems you have answered your own question. Order is in the mind of the beholder. Humans compulsively seek order, randomness makes them very uncomfortable. If the God of determinism did not exist, we'd have to create him.Belindi said: Or is there order which is not causal order? ... Determinism does not of course imply nothing but causal chains.
Causal chains, billiard ball kinetics, ant farm behaviorism... arrest the jungle again, it's drunk and disorderly.
2023/2024 Philosophy Books of the Month
Mark Victor Hansen, Relentless: Wisdom Behind the Incomparable Chicken Soup for the Soul
by Mitzi Perdue
February 2023
Rediscovering the Wisdom of Human Nature: How Civilization Destroys Happiness
by Chet Shupe
March 2023