Well, I must say that I am surprised to see that this conversation got out to seven pages without my ever hearing about it, but oh well, it's fine. (A lot of the discussion doesn't seem very relevant to my emails anyways!) Basically, I am here because it was my first time googling myself. I am vaguely surprised at how many Chris Drosts there are!
Points relevant to this discussion:
(1) A lot of the mathematical notation has been garbled in the above email; apparently either Tom's email client or his message board software cannot handle unicode. If your browser and fonts can handle UTF-8 encoding for special characters, and you want to follow basically all of the ideas from the core outward, I have typed up something much more extensive here:https://github.com/drostie/essay-seeds/blob/master/physics/doubleslit.md
The above will introduce you to Dirac notations, density matrices, and the double slit experiment. Unfortunately it may not be 100% accessible at this point, which is why I have it filed in my github account as an "essay seed" -- it might one day germinate into something much more fruitful, but now it is kind of in a "raw form." (I have tried to specially polish it since I am linking it here now, though. But it is still not a totally-lay explanation.)
(2) Tom described me as a physicist. I feel uncomfortable with this because I do not have any formal degrees from any institution in any branch of physics. I spent three years in the Applied and Engineering Physics department at Cornell University and am now trying to complete a Master's degree in Applied Physics at the Technical University Delft, in the Netherlands.
(3) Tom summarized our email exchange by saying:
the main issue (other than out of date terminology) was my claim that physicists in the 1920s realized that it was the recording of the measured data rather than the measurement itself that was critical to the outcome of the double slit experiment. Indeed that is not true. As Chris points out, physicists assumed (and still do) that it is the interaction with the measurement apparatus, rather than the fact that measured data is recorded.
This is at least somewhat misleading. I was trying in that email (and in the above link) to show Tom the effects of decoherence theory, which is actually much more recent than the 1920s idea, and properly came into its own only in the 1970s with the work of Zurek. It is not an assumption but a prediction inherent in the mathematical structure of quantum mechanics.
(4) Tom also stated
In any case, which ever assumption is shown to be correct, there is no impact on fundamental MBT theory presented in the books or presented in the workshops (YouTube). It is primarily a matter of me getting my history right at best and not attributing to current physics understandings that they don't have.
I guess this is a matter that I should take up more privately with him, but I think that it could have pretty dramatic impact on the MBT. The problem which this little almost-nitpicky point raises -- "you don't have to actually measure the slit the double-slit photon went through, rotating it by ± 45 degrees depending on which slit it went through is enough" -- is the sort of problem which makes it very hard to take any consciousness-relative theory of everything seriously.
That is, if one is going to say "we live in the Matrix," this little point means that the Matrix is actually keeping track of all those variables
which we aren't so concerned about. The Matrix cares that the photon was rotated! We didn't even have to observe its rotation with a big macroscopic apparatus to tell the Matrix "hey, you, I want to observe this thing over here"; the Matrix is keeping track of all of these little variables.
In other words, our Sun is a typical star with a power output of 4 * 10^26 J/s. It's a yellow star, so it's emitting photons of, say L ~500 nm, which gives a typical photon energy of E = h c / L = 4 * 10^-19 J. This means that every second, the Sun spits out 10^45 photons. (We can even see that the Sun is essentially a quantum beast by looking at the spectrum of that light, which is a blackbody spectrum -- Planck's initial motivation for quantum mechanics, and his basis for calculating his constant h.) I am not even going to consider the fact that there are over a hundred billion stars in the galaxy.
What matters is simply this: The polarization of a photon is in quantum mechanics a nice little 2-level system, can be up-down or left-right or some superposition between the two. If we can get our photons from anywhere, and the Matrix is keeping track of the states of all photons while performing proper quantum manipulations, then we have a huge problem.
The set of basis elements which quantum mechanics needs in order to describe this system is therefore 2^(10^45). If you thought 10^45 photons was big, you cannot imagine this number. In scientific notation it would be, to five significant figures,
2.8980 * 10^(301,029,995,663,981,195,213,738,894,724,493,026,768,189,881).
So unless someone decided to make a computer with that many circuit elements in it, quantum mechanics would have to break down every second when considering the photons coming out from the Sun -- the computer just couldn't handle them all.
(5) In addition, I think that the lesson you're trying to derive from quantum measurements is something like "the universe is consciousness-relative," which is the only reason I can see for connecting quantum measurement with a virtual reality idea. But quantum measurements have many properties which wouldn't strike you as consciousness-relative. One of them is discussed in the above notes: you can, in general, postpone any measurement until the end of an experiment, trading any classical operations done with that classical bit into quantum operations done with that qubit. (The reverse of this is actually what makes quantum teleportation look surprising. It doesn't look so impressive when you make controlled-Z and controlled-X gates from one qubit to another, but the idea that you can move the measurements earlier than these operations and just do them classically by sending two classical bits makes it seem very surprising indeed.)
I mean, if you want to be a proper theory of anything, you should be making predictions -- that's just how scientific theories work. I mean, something as simple as "the observable universe might only have 10^80 particles and we might guess that even if you had an entire observable universe of circuit elements for each of those particles, you'd only have 10^160 or so circuit elements -- bottom line, the the computers which simulate our reality probably don't have more than 10^(301) elements, therefore quantum effects cannot happen in any system with more than 1 thousand parts" would be a good starting place. I know of at least one paper which entangled ~100,000 Rubidium atoms in an optical lattice
. I'm sure that only scratches the surface.
(6) I wish to clarify the above by saying that I don't pretend to understand the MBT, and from my discussions with Tom, I simply came away with the understanding that it was not a theory of anything in particular -- that is, I came away with the impression that there were no physical tests to be made of his ideas. Perhaps that was a wrong impression from me; I don't know. I just gathered that it was a virtual reality theory motivated by quantum weirdness, and I sought to correct some misunderstandings of that quantum weirdness, so as to motivate a better inquiry into the whole picture.