The ‘one bit per elementary particle’ idea might or might not be true, but it offers a way to think about the issue on which quantum mechanics seems to pronounce very clearly: we can’t know everything. The maximum information we can possibly know about a quantum system is not the complete information that specifies everything about how that system might behave. And the residue is not simply unknown; it is unspecified. We should probably not say that those other properties don’t have fixed values, but rather that, being unmeasured, they are not even properties.
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