But our universe, as well as a theoretically deterministic universe, necessarily, certainly contain many mixed states. And, I didn't use the term data first. B

But our universe, as well as a theoretically deterministic universe, necessarily, certainly contain many mixed states. And, I didn't use the term data first. But when I used that word I was trying to transmit the meaning of "content", "substance", or character, nature, or what exists in the matter/issue. What is in the principle of a system's operation. How do I establish given a wave function the amount of data that it holds? A wave function doesn't exactly contain data. You either prescribe a wavefunction, or try to model one based on hypothetical constraints, or you can attempt to guess what an existing actual wavefunction was through measurement. As I mentioned I think when we say data we're usually talking about what is measured. But there is something more that exists than what is measured. Something that you could say is invisible doesn't not exist if it determines everything else that exist. If you understand everything about an object or a system you can prescribe an exact wavefunction. But we do not understand everything about what is in the objects for which we have tried to prescribe wavefunctions. What am I claiming exactly? I was not claiming anything, although now I have made a claim at the start of this comment; but I was asking a question as to whether 'mjburgess' was merely phrasing his original comment to make it seem to the careless reader or undiscerning eye that 'If the future "holds more data" than the past then it's random with respect to the past, by definition. This is one of the major interpretations of QM.' was actually "If the future "holds more data" than the past then it's random with respect to the past, by all possible definitions (implicitly). This a conclusion finally reached by physicists after having studied QM, rather than merely one possible interpretation given the best theory available so far.' but they indeed did not write that.