- #141
Ken G
Gold Member
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Some work has been done in this thread attempting to supply a scientific meaning to "physically real." That is of course essential if we wish to give a scientific answer to "is the wave function physically real." But I think the actual problem here is that there is only one scientific meaning to "physically real" that holds up to the process of science itself, and that is essentially the meaning "whatever we say is physically real." In other words, "reality" is our word, and we are the ones who say what it shall mean to us, it is not a word picked out of some pre-existing language that we only dimly understand because that is just not what language is.
As such, it is simply the wrong way to ask the question to frame it is as "which of the devices and concepts invoked by science are the ones that are actually physically real, and which ones are not", the question must be posed as "what whall we mean by physically real such that the devices and concepts we wish to manipulate may be regarded as having that property." In short, the question is not if the quantum state is physically real, it is, given the observed attributes that quantum states have (ability to be nonlocally entangled, inability to provide simultaneous answers to all hypothetical questions that could be put to the state) do we want the quantum state to be physically real, or don't we? You must answer that question first, or you are spinning your wheels. Because the simple truth is, some do want that state to be physically real, because they want to be able to talk about it that way, and others do not, because they want to be able to talk about physically real things as having properties that quantum states do not.
Framed like this, we put the question in its proper context: it is not a physics question, and it is not even a philosophy question-- it is a sociology question. We don't get to decide what a quantum state is, that is constrained by how it is found to behave, but we do get to decide what we want "physically real" to mean, in our modern scientific society. And that meaning is not handed to us in advance because nothing is handed to us in advance in science, we have to explore every nook and cranny ourselves, and it is not common sense because science is constantly challenging the idea that common sense is likely to be correct. We have to be scientists first, and then we have to ask what is physically real, and when we do that, the answer always comes out something like "what we mean by physically real is nothing but our current understanding of the situation, whatever that is." So I would say that the quantum state is indeed physically real, but not because it has attributes that conform to what is physically real-- instead, what is physically real must conform to the attributes of the quantum state, because why would we want our most fundamental understanding of nature to be not what we mean by what is physically real?
As such, it is simply the wrong way to ask the question to frame it is as "which of the devices and concepts invoked by science are the ones that are actually physically real, and which ones are not", the question must be posed as "what whall we mean by physically real such that the devices and concepts we wish to manipulate may be regarded as having that property." In short, the question is not if the quantum state is physically real, it is, given the observed attributes that quantum states have (ability to be nonlocally entangled, inability to provide simultaneous answers to all hypothetical questions that could be put to the state) do we want the quantum state to be physically real, or don't we? You must answer that question first, or you are spinning your wheels. Because the simple truth is, some do want that state to be physically real, because they want to be able to talk about it that way, and others do not, because they want to be able to talk about physically real things as having properties that quantum states do not.
Framed like this, we put the question in its proper context: it is not a physics question, and it is not even a philosophy question-- it is a sociology question. We don't get to decide what a quantum state is, that is constrained by how it is found to behave, but we do get to decide what we want "physically real" to mean, in our modern scientific society. And that meaning is not handed to us in advance because nothing is handed to us in advance in science, we have to explore every nook and cranny ourselves, and it is not common sense because science is constantly challenging the idea that common sense is likely to be correct. We have to be scientists first, and then we have to ask what is physically real, and when we do that, the answer always comes out something like "what we mean by physically real is nothing but our current understanding of the situation, whatever that is." So I would say that the quantum state is indeed physically real, but not because it has attributes that conform to what is physically real-- instead, what is physically real must conform to the attributes of the quantum state, because why would we want our most fundamental understanding of nature to be not what we mean by what is physically real?