I The Probability Distribution and 'Elements of Reality'

[Fra]

That would be a separate discussion. I'm simply saying, if we can deduce or infer that there are "things" which exist but that cannot be observed, then we cannot have a complete description of those "things" if our description only describes the outcomes of observations.

If we can infer that there is something, that inference must follow from physically possible processing of physicall possible observations. (This is a constraint in my own view at least).

So not necessarily direct observations, but indirect where you observe the black box response to perturbation? In that case, it IS indirectly abducable. (A subnote is that an abduction unlike deduction is not unique, so another selection principle is requirrd).

With observable in this sense, I am not talking about the constrained limited sense of an observable in QM. It wouldn't make sense to limit ourselve to thta notion when discussion the foundation and possible reconstructions of QM itself. With observable in the general sense, I mean abducable or inferrable, FROM actual observations, BY the information processing capacit of and agent/observer. Here both the distinguishable events, as well as the information processing capacity of the agent is limiting the inferrable theory. So in this thinking the theory itself "scales" or evolves non-trivially with the agents microstructure and total capacity.

Perhaps the disagreement here is due to my perspective. Almost nothing is directly observable in the naive sense anyway, right? So for me, indirect observations qualify as observations, but they require post-processing. If this is what you mean, then perhaps I agree with that you say.

/Fredrik

 

[Lord Jestocost]

If find this just about as annoying as people that still today keep thinking that "observation" in QM has anything todo with conscious human observers.

Annoying isn't a scientific term.
One should, as John von Neumann has done, merely rely on the unambiguous mathematics constituting quantum theory. The quantum mechanical time evolution is valid for all "physical systems". That's the reason why all “quantum processes” finally boil down - in mathematical language - to something like a purely quantum-mechanical von Neumann measurement chain when physical systems are interacting which each other.
And what happens at the end of such a purely quantum-mechanical von Neumann measurement chain?

 

[WernerQH]

if we can deduce or infer that there are "things" which exist but that cannot be observed, then we cannot have a complete description of those "things" if our description only describes the outcomes of observations.

Interesting. Would you say that Maxwell's electrodynamics was incomplete? He believed in the existence of an ether, but was his conviction based on deduction or inference? With hindsight, we would nowadays answer "no" to this question, but for Maxwell the existence of the ether was probably as firmly established as the existence of "systems" with some kind of "location" is for you.

 

[Fra]

Annoying isn't a scientific term.

I just find it misleading, and that is annoying. Ie. the association of "observers" with humans, is to me a mischaracterisation of something, to admittedly make it look less appealing.

The quantum mechanical time evolution is valid for all "physical systems".

Is it? But what IS the unitary evolution? To me understanding it does not rule what actually happens, it is merely an expectation of the evolution. This is problematic when the part of the universe which has inferred and stored the expectation, becomes not a passive observer, but an active participant in the interaction. This is where this abstraction has a problem IMHO.

That's the reason why all “quantum processes” finally boil down - in mathematical language - to something like a purely quantum-mechanical von Neumann measurement chain when physical systems are interacting which each other.
And what happens at the end of such a purely quantum-mechanical von Neumann measurement chain?

I am tempted to say that at the end of thihs von-neumann chain, we have a remote future scattering matrix?

/Fredrik

 

[Lynch101]

If we can infer that there is something, that inference must follow from physically possible processing of physicall possible observations. (This is a constraint in my own view at least).

So not necessarily direct observations, but indirect where you observe the black box response to perturbation? In that case, it IS indirectly abducable. (A subnote is that an abduction unlike deduction is not unique, so another selection principle is requirrd).

With observable in this sense, I am not talking about the constrained limited sense of an observable in QM. It wouldn't make sense to limit ourselve to thta notion when discussion the foundation and possible reconstructions of QM itself. With observable in the general sense, I mean abducable or inferrable, FROM actual observations, BY the information processing capacit of and agent/observer. Here both the distinguishable events, as well as the information processing capacity of the agent is limiting the inferrable theory. So in this thinking the theory itself "scales" or evolves non-trivially with the agents microstructure and total capacity.

Perhaps the disagreement here is due to my perspective. Almost nothing is directly observable in the naive sense anyway, right? So for me, indirect observations qualify as observations, but they require post-processing. If this is what you mean, then perhaps I agree with that you say.

/Fredrik

There may perhaps be nuances that I am not picking up, but I think we largely agree.

To use the Schroedginers kitten example I've used elsewhere. If we put a pregnant cat into a box and a while later we open it and find a cat and a kitten. We can deduce/infer/abduct (I'm not sure which is the correct term here) that the kitten was in the box prior to our observing it.

 

[Lynch101]

Interesting. Would you say that Maxwell's electrodynamics was incomplete? He believed in the existence of an ether, but was his conviction based on deduction or inference? With hindsight, we would nowadays answer "no" to this question, but for Maxwell the existence of the ether was probably as firmly established as the existence of "systems" with some kind of "location" is for you.

If systems don't have any position whatsoever in 3D space, either they don't exist or they operate in more than 3 dimensions.

I'm not sure if the ether is analogous in that sense.

 

[WernerQH]

I'm not sure if the ether is analogous in that sense.

Of course one could say that Maxwell's electromagnetism was "incomplete" in a sense quite different from quantum theory (although it was successful and passed all experimental tests). Too bad you can't perceive the analogy.

 

[Lynch101]

Of course one could say that Maxwell's electromagnetism was "incomplete" in a sense quite different from quantum theory (although it was successful and passed all experimental tests). Too bad you can't perceive the analogy.

I got the analogy. It was a weak one.

 

[WernerQH]

I got the analogy. It was a weak one.

The point I was trying to make was that different people, at different times, can disagree on what "exists".

 

[Lynch101]

The point I was trying to make was that different people, at different times, can disagree on what "exists".

I know. It was a weak analogy bcos it didn't really characterise the specific question. You could equally have said that people used to believe that fairies exist.