Haven’t been posting much but I have continued to think and read up on all this. I’ve even started trying my hand at translating the math, though I’m not ready to post on that yet!
I’ve been really trying to figure out these Von Neumann chains, what processes 1 and 2 are supposed to actually represent, and to understand Stapp’s take on it. Stapp certainly doesn’t make it easy since he refers to what VN wrote but often uses different terms - including framing the math differently. I don’t mind him putting his own spin on things, I just wish he’d clearly indicate when he’s representing VN’s position vs. his own extrapolations!
Anyway, getting back to it.
Neil: when we’ve talked about VN chains, I got the sense that you are envisioning a chain with potentially ever expanding links, potential intervening events, so long as it ends up in an observation. For example, I think you and Paul were talking about a hypothetical scenario where different elements are added after the measurement, for example, ringing a bell (or not ringing a bell) which is perceived (or not perceived) by the observer leading to a collapse of the wavefunction.
Please correct me if I’m wrong on that. In any event, I’ll set out how I interpret it so far:
The way I’m reading it, the chain as VN sets it out the chain really doesn’t go beyond I (the system being measured), II (the measuring apparatus) and III (the observer).
VN describes how his chain can be expanded. Paraphrasing, we can just say we observed x. We can go further and say that we took in wavelengths of light through our eyes and then observed. Or further going into the chemical processes involved and then observed. And he hypotheses that perhaps later discoveries would allow us to break down the process even more, and each time we have to end with: “and is observed by the observer.”
But notice that when he expands the chain he’s not really adding new events in addition to I, II, and III. When VN expands the chain, what he is setting out is the nested way we can describe the process of observing. In other words: the length of the "chain" doesn't vary, only the level of detail in which we describe it. It’s a string of nested descriptions – but each are going on every time we observe – there are no added steps. Note that I don’t think VN himself used the term “chain” (which does imply, I think that links can be added) – I think it’s a bit of a misnomer.
I think part of the problem is that he frames it as ending with “and is observed by the observer”. This suggests that the observation takes place at the end of the chain. But taking an IIT approach I think there is overlap: at one point the observation and the process described in the chain become the same. That is: the wavelengths of light must go to our eyes before the observation happens, some processing may go on before we have the conscious observation but at some point the process being described has the phenomenological property that we call observation. In other words: the chain can be described as: information flows from the measuring apparatus to the eye, into the brain, certain electrico-chemical processes take place that results in the information being integrated into the system. That integration of information has the phenomelogical property of a conscious observation. The observation is a different side of information processing coin: but I don’t think we can say, in this model, that the observation is a final step (or if we do, it’s a shared final step).
I’ve got to read it a bit closer, but if I understand correctly, VN describes the observation of the measurement as something that has to happen right at the time the measurement takes place, otherwise the wave function will continue to evolve and we will lose that information (I’m still working on deciphering this bit though, so I may be off here). Recall, that he’s writing at a time where the results of measurement were not recorded by the measuring apparatus. You had to look at the pointer at that time, you had to look at the thermometer at that time.
This highlights the point that we should be clear on what we are observing. We are NOT observing the object being measured (ie: the particle). As VN explains, the reason we need to combine I (the system being observed- S), II (the measuring apparatus – M) and III (the observing system) is that we can’t observe I on its own. We can only do it in conjunction with II (S + M). That is what Process 1 is describing, as I understand it – the intersection of those two systems.
Ok, have to break here – will continue later.