On 18 Jan 2014, at 05:27, LizR wrote:
On 18 January 2014 17:16, meekerdb <[email protected]> wrote:
On 1/17/2014 5:40 PM, LizR wrote:
But apparently the brain has a lot to do with those computations in
Platonia, c.f. anesthetic. Notice that I'm not a disciple of
Platonia.
Me neither, I am agnostic - but within comp it is assumed, so while
discussing comp we have to assume it (unless we're rejecting comp
on that basis). But I can see that Platonia makes sense in that 17
does seem to be prime idependently of you and me and everyone else,
which is (I'm told) enough for the whole shebang to come into some
sort of existence.
I don't think you have to buy the equivalence between (17 is prime)
is true and (17 is prime) exists. In fact Bruno always says you
only have to believe the first for his argument to succeed. But
then he slips in the UD and it seems that every truth of arithmetic
implies and existence. I think this is the same problem as step 8.
If everything has to be simulated, then there's no difference
between simulated and real. If I'm "really" existing in an
infinity of world/simulations that are *just like this one up to
now* - then they ARE this one (c.f. Leibniz).
Well, I haven't managed to get my head around step 8, at least, not
if step 8 is the MGA? (Or maybe I did, if it isn't....)
May be there is a simpler argument than step 8 (MGA). It is the fact
that you need magical (non Turing emulable) matter for a machine being
able to distinguish "real matter" (what could be that?) from its an
arithmetical emulation.
So, even without the MGA, you can understand that the notion of "real
matter" can only be a reification of an unknown (real matter) to
prevent the use of a simple theory. This makes already the "real
matter argument" like a creationist god-of-the-gap.
MGA just extends this in showing that not only that "real matter" is a
reification, but that it needs some quite ad hoc components. Not all
philosophers are against reification, so MGA makes the absurdity of
doing that reification (in this context) much more palpable.
I suppose what I need to know is how the existence (in any sense) of
the integers and elementary arithmetic operations creates
computations.
Yes, that is a key point. It is not simple to explain, although more
or less standard in mathematical logic.
The problem here is that we must distinguish between a computation and
a description of a computation, and understand that if RA can prove
the existence of a computation only through the existence of a
description of a computation, then the computation exists. This is
subtle because it needs to see well the difference between syntaxical
sentences and semantical statements, ...
We can come back on this. It is well done in some books.
In fact every possible computation. I believe it's done indexically,
whatever that means ... but I think this is about where I start to
feel I shouldn't bother my pretty little head.
If the sheer existence of numbers, + and x implies that all possible
computations "exist "(in an abstract sense) then it all follows - in
an abstract sense.
Yes, and the concrete experience will exist too, in that abstract
sense, and that's is enough for the existence of indexically concrete
experience. Tegmark is right on this (but not original in the prior
publication sense).
This brings me back to your comment about equivalence (or not). The
thing is, I'd like to know what I'm buying or not buying before I
decide whether to buy it!
You need to buy only two things: "yes doctor" and Church thesis. AR is
implicit in Church thesis (and in the whole of science, I would add).
Bruno
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