On 12/9/2013 2:36 AM, Bruno Marchal wrote:
On 09 Dec 2013, at 09:44, LizR wrote:
On 9 December 2013 20:56, meekerdb <[email protected] <mailto:[email protected]>>
wrote:
On 12/8/2013 4:36 PM, LizR wrote:
On 9 December 2013 07:41, John Clark <[email protected]
<mailto:[email protected]>> wrote:
On Sun, Dec 8, 2013 at 11:48 AM, Jason Resch <[email protected]
<mailto:[email protected]>> wrote:
>> Determinism is far from "well established".
> It's a basic assumption in almost every scientific theory.
In the most important theory in physics, Quantum Mechanics, no such
assumption
is made, and despite a century of trying no experiment has ever been
performed
that even hinted such a deterministic assumption should be added in.
I believe the two-slit experiment hints that QM is deterministic by
implying the
existence of a multiverse.
Wasn't it you, Liz, that pointed out this was circular. Everett assumes a
multiverse in order to make QM determinsitic.
I did say something like that, didn't I? [insert embarrassed emoticon here].
I think I was saying that it was too strong to say that QM "follows the principle of
determinism" (or something like that) because it appears to be indeterminate and only
becomes deterministic thanks to Everett. However, the two-slit experiment does
/suggest/ the multiverse as a valid explanation, in that any other explanation requires
other principles to be violated (causality, locality...)
I think I was attempting to position myself between John and Jason - to say that
determinism is reasonably well established,
I am not sure we can establish anything about nature (nor even that it exists in some
ontological) sense. But we can say that up to now, all our theories are deterministic,
Actually only a handful of theories: mechanics and electrodynamics were deterministic.
There was great resistance to them at first because the "tied the hands of God". Then
theologians explained that God was the "law giver" so it was OK. Probability theory was
developed later and there were many applications of it (Poisson predicted the incidence of
injury due to horse kicks in Napoleon's army) - but because it was assumed that there were
"laws of nature" laid down by God, the indeterminism was assumed to be due to a lack of
information. But if you take QM to be indeterministic you find that quantum randomness
gets amplified to classical "lack of information" pretty quickly. When QM was found to be
probablistic there was again great resistance because "God didn't throw dice".
which is assuming less than to assume the existence of something non deterministic,
which for me is close to a fairy tale idea (just looking more serious, but belonging to
the same kind of insanity, to use Einstein's wording).
Theories are human inventions. Humans liked determinstic theories because they give
definite answers. Even in engineering problems it is always complicates things a lot when
you have to use probabilistic analysis, e.g. in aircraft structural life calculations:
Simple maxima and minima get replaced by probability distributions. Multiplications get
replaced by convolution integrals. Simulations become Monte Carlos. Management wants to
know exactly how much it will cost - not a range.
It is more likely that determinism is a fairy tale we select from the world because it's a
more pleasant story than reality.
Brent
Obviously, for people believing in both QM and a unique physical reality (a
mono-universe), it looks like there is a 3p indeterminacy, but computationalist have an
easy theory explaining this necessary indeterministic first person (even plural with QM)
appearance.
QM (without collapse) makes going away any 3p indeterminacy, and 3p non locality. Comp
makes this into statistically predictible explained appearance.
But then comp adds once important thing: the SWE (i.e. QM itself) *must* be deduced from
a larger statistics on all computations.
And "all computations" makes sense through the "miracle" of the
Church-Turing-Post-Kleene thesis.
Once you accept, like John C., that there are events without cause, I think you believe
in magic.
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