There is a difficulty in quantum theory here (it is THE difficulty in fact). Consciousness is sometimes called upon as a deus ex machina to get out of the riddle (I'm one of those doing that).Antiphon said:I would add to that that that the observer does not need to be a conscious
entity. A recording device can perform valid measurements even if no
conscous entity ever checks the results.
How do you differentiate 3) and 1)? By defining an ontological and non local object "consciousness" (or a god)? Aren't you defining, in fine, a bohmian like interpretation of QM with point 3 (i.e. we may view the bohmian path as the consciousness of the particle in fine )?vanesch said:So how to reconcile this:
1) you can claim that the wavefunction is just a description of our knowledge of the system (like a kind of probability distribution), and of course it changes when we learn things about it ; this explains the collapse into one of its terms. But that is a disturbing viewpoint IMHO, because then there's nothing left that describes "the world out there". We don't have then a theory of the world, but a theory of our knowledge! But knowledge of what ? As we don't have a description anymore of what we're knowing things of, we just "know" and describe that, we don't know things "about" something, because that something lacks totally a decription. Strange, for a physical theory.
2) Unitary quantum theory doesn't apply universally. So that then implies a modification of the theory to tell us what does apply universally, and how it simplifies to unitary QM for microscopic systems. This is very difficult to do !
3) Unitary quantum theory does apply universally, and these macroscopic superpositions do happen but we consciously observe only ONE term. This is where consciousness tries to save us. This is Many Worlds. Also strange, for a physical theory!
My point is 3) until we finally find 2)
My preference of 3) over 1) is that although it is very strange, at least there IS a world out there which is described. I've difficulties letting that go.
2) is still very remote, if ever. QM is more successful than is confortable. I'm hoping somehow for gravity to settle the issue...
There is a subtle difference, but you are right that 3) has some points of similarity with Bohm, except, and that's the whole thing: the non-locality! With individual minds travelling each LOCALLY their own path, you can save locality, while Bohm has one and the same "token indicating which branch" for ALL, space-like connected, observers. As such, this unique and universal token had to obey a non-local dynamics in order to coincide with QM and this is with us for ever, thanks to Bell's observations.seratend said:How do you differentiate 3) and 1)? By defining an ontological and non local object "consciousness" (or a god)? Aren't you defining, in fine, a bohmian like interpretation of QM with point 3 (i.e. we may view the bohmian path as the consciousness of the particle in fine )?
Well, it should at least contain such a description, and the purely epistemological view denies that from the start ! After that, we can discuss what is allowed in the description, but at first there MUST be a description.Physics after all is all about the description of the "reality", therefore it should be independent of such concepts, shouldn't it?
The difficulty with that point of view is then that the system's dynamics is influenced by what we know about it !DaTario said:Regarding the OP, Schwinger has said once:
Quantum Mechanics is a symbolic representation of our knowledge about the experimental results on a microscopic scale. Simple, insn't it?
Quite the contrary. We know from lot's of empirical evidence that learning is a function of electrical and chemical processes in the brain and nervous system. We know similarly, that recognition and (possible) memorization are governed by elctrically and chemically induced neural pulses with corresponding physical changes in neurons and brain-structure. That's all you need for collapse.Galileo said:I believe Eugene Wigner was the man who believed human conciousness causes a wavefunction to collapse. It seems like a difficult position to defend.
Could you please provide examples of physical processes that depend on wave function collapse?Galileo said:But a lot of physical processes depend on this collapse of the wavefunction. The point of view you're describing implies these processes do not happen if there is no consiousness to detect it? That's like saying the moon is not there when nobody looks.
My photodetector behind a beamsplitter does not go off after I fired a photon, but is in a superposition of detection/no-detecion until I check whether it really did or didn't go off? That sounds awfully nonphysical and suspicious to me. The wavefunction clearly does not decribe anything real in this view.