That's basically right-- but note the real implication is that what people call "interpretations of quantum mechanics" are really no such things, they are interpretations of the meaning of probability. To be a true interpretation of quantum mechanics, you must be interpreting the meaning of a pure state, but the way most people use the term, they are interpreting the meaning of a collapsed wave function, i.e., a substate
of a pure state that also includes a dramatic and untraceable degree of decoherence. In short, a quasi-classical system!
I agree, this is a key question. I say, it did not, yet many people think that it did. I don't know why, I think it's because they imagine that pre-quantum physics was purely deterministic and did not involve probabilities. It is as though they have forgotten thermodynamics and weather forecasting.
My answer would be "I find it very useful to adopt the picture that at any time the Moon is either there or it isn't, but I recognize that no science requires this-- science only requires I can identify a probability that the Moon is there, a probability that may go completely unactualized until I look."
I think decoherence occurs naturally, but decoherence only yields probabilities, not actualities. So it depends on what you mean by "observation"-- most people mean the demonstration of an actualization, and that does require an intelligence, because that is where the actualization "lives". However, it is an important principle of physics that all the actualizations in these intelligent minds must be consistent. No one has any idea why this is, and there are certainly gray areas, but it does seem to hold well-- and it spawns the concept of "objective reality". But saying that actualizations must be consistent is not saying the actualizations don't require minds, it just says that-- the actualizations must be consistent when intelligence further actualizes the higher-order correlations.
The problem is with the definitions. We cannot say which statements are right or wrong until we can clearly define the words, and here the tricky words are "exist" (by which I mean "a probability that has been actualized") and "observation" (by which I mean, "the demonstration that actualization has occured", and expressly not "the decohering of a substate wave function to get it to behave classically", though that is certainly a key element
of observation). I maintain that taking these definitions, an intelligence is required to have an observation, because there is no way to demonstrate that an "actualization" occured, and no way to distinguish it from a "probability", without one.
In other words, you can program a computer to generate a random number (pseudorandom is good enough for me), and it can send that result to another processor, which sends its result to another, and so forth. I would say the issue of at what point this constitutes an "intelligence" is exactly the point at which one can treat that original random number as "actualized". Prior to that point, you can still treat it as a probability distribution, and just propagate that probability distribution through all the subsequent processing, generating new probability distributions. At the point where you can say "treating this as a probability no longer gives useful predictions", then you have an intelligence. So it's not that "intelligence actualizes observations", it is "the actualization of observation is the definition of intelligence".
Whether that intelligence counts as "human" is an even murkier topic, that will probably have to wait until we have the first clue of how to differentiate "human intelligence" from other forms. I'm not sure we know what should qualify as human intelligence, any definition would seem to either leave out too many humans, or not leave out enough non-humans.
This certainly underscores the problem of definition. We probably need to do a lot more work around what is meant by these words, or we can have purely semantic differences disguised as real disagreements.
I certainly believe it is not possible to predict the throw of a die no matter how well you prescribe its initial conditions, if the throw "mixes in" enough of the details of the environment. For example, you could specify the initial velocity and angular momentum of the die, but only to the precision of your instrument, and you have to propagate whatever uncertainty exists initially through a lot of exponentially magnifying factors. You can specify the amount of sound in the room, but that's not good enough-- you need to know the amplitude and phase of every vibration that could affect the die. You need to know not just the windspeed, but every eddy current in the air. You need to know not just the dimensions of the rolling area, and the material properties of the surface, but how it varies with position and whether or not "material properties" are defined suitably precisely in the first place. In short, the prediction is doing physics, whereas the "reality" is only the roll of the die itself. And to do physics, we make idealizations and approximations at every stage. At some point, we just throw up our hands and say "forget tracking these details, we're just going to average over what we don't know and make some kind of ergodicity assumption"-- and poof, we have no more than a probability, even in principle
, at that moment. Since this is an inevitable component of Newtonian mechanics sooner or later in any complex system, we could never
have said that the universe was deterministic, it would simply not be scientifically demonstrable long before quantum mechanics.
That is indeed what I would say-- what do you mean by their "status in the Kopenhagen interpretation?"
Yes, it is a superstructure, and it is also an integral part of Newtonian physics. That's why the latter was never fully deterministic, it was more like asymptotically deterministic in a way that was purely philosophical. Did anyone think that Newton's laws turned thermodynamics into some kind of placekeeper until fully detailed predictions could be made?
Excellent point, and crucial to understanding why determinism was always a red herring-- it was contradictory to the notion of irreversibility, which is a hugely important physical concept.
You can claim to reject it, but if you actually apply it, then the claim is irrelevant. To actually reject the axiom, you have to find a way to do without it-- you have to find a way to do science that does not look like confronting an intelligence with experimental results that actualize the results and compare them to probabilistic predictions over a sequence of trials. I am completely at a loss as to how you imagine you can do science in some other way.
But I'm not selling a philosophy, I'm challenging you to use your computer to do science without an intelligence! Remember, if the computer encounters a probability distribution of outcomes, then it generates a probability distribution of recordings and analysis. There is simply no way you can demonstrate it has done anything different, without invoking an intelligence to actualize the distinction. You can imagine that the result was actualized, and indeed we all do, but science is completely moot on the issue
-- it doesn't need to take a stance and therefore should not
(why would science take a stance on a matter it is moot about?). But science must take a stance when an intelligence actualizes the result, because that is a truth that must be contended with, indeed it is the very point of doing science to generate that truth. Science is an endeavor of an intelligence, surely that at least is noncontroversial.
That is not what I mean by "classical"-- I simply mean a system we choose classical mechanics to describe
(more definitions in need of clarification). It has nothing to do with what is "right" and "wrong", those are unsophisticated notions in human endeavors like physics-- it has to do with what we choose to do to solve a problem.
Of course not-- what is precisely quantum mechanical? Nothing real is "precisely" anything.
I cannot sway you from your beliefs, and don't want to-- but those exceed what science can tell us, and I am trying to keep careful track of where that line is.