> On 17 May 2018, at 16:30, tozziart...@libero.it wrote:
> Dear Bruno,
> as far as you wrote and I understood, your Mechanistic framework requires the
> tenet that quantum wave collapse does not exist.
> In order to prove that, you invoke the authority of Everett.
I refer to Everett, but the truth is that I have never been able to make sense
of the collapse of the wave packet, which simply contradict the wave equation
and thus introduce a dualism, which is never well defined. It is obviously an
axiom added to make disappear the other worlds, to fit the appearance. Everett
just realise it was not needed, and it solved very elegantly the so called
measurement problem. It makes physics back to realism, determinism, locality,
and this in a way consistent with Computationalism (aka Mechanism).
But note that I did prove already (well before I knew QM and Everett) that
Mechanism alone implies a “many-worlds” or “many histories” interpretation of
arithmetic (or of any Turing universal system).
> I want to provide a simple, very rough explanation (excuse me!), for the
> FISers unaware of the Everett's account:
> You are in front of two streets, one turns left and the other turns rigth.
> You have to choose where to turn.
> If you turn left, you could not anymore turn right.
> This is, very roughly speaking, what quantum wave collapse means: if you make
> a choice, it is irreversible in our Universe.
> In order to avoid such irreversibility, Everett, who did not like quantum
> wave collapse, provided the following account:
> every time you have to choose whether you have to turn left or right, the
> entire Universe splits in two different Universes: in one Universe you turn
> left, while another you turns right in another Universe.
This is oversimplifying and is actually importantly wrong, if you don’t mind.
Let us assume that the brain is not a quantum computer (as an hot object, this
is believed by most scientists). If you choose where to turn, with mechanism +
Everett, you will not split the reality in two.
To split the reality in that situation, you need to prepare a particle in a
quantum superposition state, say
1/sqrt(2) [ up + down]
With up and down being some quantum attribute (like a stern Gerlach spin
measurement device, in some fixed direction of space), and you have to
correlate your decision to go left or right according to the measurement of the
spin (say), like to decide that if you find the spin up you go left, and if you
find spin down.
So, that is really not a choice. Subjectively, it will seem like a decision by
throwing a coin. Only in that case will the world split in two (to simplify, as
both with comp and in some reading of Everett, the physical reality does not
split, it is consciousness which differentiate in two histories, and that
splitting propagate to the entire universe at a speed slower than light, just
This follows from two fundamental features of QM:
1) the linearity of the tensor product ( A (up + down) = (A up + A down), with
A being for example the measuring instrument, then the observer, etc. The
superposition is “contagious” on the environment.
2) the linearity of the state evolution, which explains that in each branch the
evolution of the physical acts like if they has not have been any split.
> Now, dear FISer, tell me if the Everett's approach is tenable or it is not,
> and, if your answer is that it is tenable, tell me how it could be even
> theoretically demonstrated.
It is demonstrated in the sense that it follows from the literal reading of
If A is the observer, and “A-up” means A having seen “up” (and A-down = A
seeing “down”). And if A look at the particle spin, we have:
(A down + A up) ==> (A-down down + A-up up).
The observer consciousness has split into seeing up, and seeing down. But with
mechanism and the linearity of evolution, the observer does not feel the split,
like in the mechanist first person indeterminacy in a classical
This will evolves, in our case into two histories:
(A-down turning left down. + A-up turning right up), etc.
So we get the explanation of the subjective (first person) indeterminacy
without third person indeterminacy in nature. The quantum indeterminacy is
explained by the (older) first person indeterminacy provided by
Evidences that Nature obeys the Wave equation is abundant. As it explains the
appearance of a collapse, without introducing a physical collapse, this theory
is conceptually simpler, and it is those who believe that there is a collapse
who have to provide the evidences. But there are none, and this makes QM
applicable to cosmology, quantum computing, etc.
And then, we get again a realist, deterministic and local theory, which is
consistent with special relativity.
The collapse postulate, on the