# Re: Is the universe computable?

```John M wrote:
>
> George Q wrote (among many others, full post see below):
>
> A."the universe in which I live according to the current intuition
> I have of it"
> and
> B:> the possibility to simulate the universe at any level of accuracy. <
>
> First I wanted to ask what is intuition, but let us stay with common sense
> (however divergent that may be). I don't have your intuition and you
> don't have mine.```
```
There is an assumption here which is that however divergent
these intuition or common sense views of it might be, there
exist (in some sense) something that we can refer to as
"the universe". By the way, this is not the first series of
post with that title and though I am not sure I went through
all of them this is the first time I see this issue discussed
here. This is indeed a good question but why me ? And how do
other participants define what "the universe" could be ?

> Now if A is true, I wonder upon WHAT can you simulate?

I don't understand the question.

Yes but this is onky in one sense. There might exist a lot
of other universes. Among all possible universes, I mean I
am talking about the one I feel I live in. This is just a
way to designate one specific universe (not to mean that I
am not interested in the computability of others but I have
a special interest in that one).

> I like better a 'mixed' way:
> MY 'interpretation' of something to which I have access only through such
> interpretation - but there must be a basis for the inter[retation both as
> my way of doing it, but more importantly the 'thing' to interpret. The
> (common sense) intuition comes into the 'my way'.

Do we really disagree ont that ?

> C. (universe:)"the smallest independent piece that does include myself"
>
> First I object to "independent" which would lead to a multiple existence
> of parallel natures (all of them singularities for the others) and we cannot
> gain information from them - which would connect in some ways. Existence
> as  we can reasonably speak about it, is interconnected - nothing
> independent.

I think we agree here. I gave indication of what I meant by
dependence (and therefore by independence) as: "space-time
continuity, particle interaction and this kind of things"
and I feel that everything in the universe is interconnected
in that way (this makes my definition of universe a tautology
but it can be linked in some way to the common sense) even
when considering "causally isolated regions of space-time"
(because these would be connected in some future and they
cannot be considered as isolated from that future).

> If you make concessions to that and accept 'relative' independence, then the
> smallest 'unit'  including you is you. I don't think you want to go
> solipsistic.

I don't believe I can isolate something like 'me'.

> If you expand further - well, I did not find a limit.

I am not sure of that. If many universes do exist, they might
well be considered independent of each other (because of lack
of spatio-temporal continuity or particle interaction or the
like).

> This is why I concocted a
> narrative about a 'plenitude' (undefined, not Plato's concept) FROM which
> distinct 'universes' occur (in timeless and countless fulgurations, callable
> BigBangs) with some INTERNAL history - in 'ours' including space and time.
> So I have a 'universe to talk about' - within my intuition <G>. And many
> more 'universes', obscured by ignorance (no info) - not excluded. I don't
> restrict 'them' to our logic, math, system, not even causality.

This sounds very speculative (not to say mystical) to me.

> I like your metaphor of the dominos. It pertains to a view we may have
> in our (exclusively possible) reductionist ways about the world: THIS
> ONE is the cause of an event (one side of the domino) while the rest of
> the system (all of it) is also influencing - whether we consider it in our
> limited model (within our chosen boundaries) or not.

I have two views of causality. In the first one, causality
is a local and macroscopic (and mesoscopic) emergent property
linked to the fact that the universe would be more ordered on
one side that on the other. In the second, events continuously
trigger other events. The second view seems to be some kind of
idealisation of the first one that will always be no more than
a convenient simplification/approximation. Considering that
everything occurs or must occur according to the second view
sounds like an error to me. This error tends to make the
universe viewed as somthing evolving through time while it
should be viewed as a static (intemporal) object within which
(the flow of) time emerges from its structure as a local
property. This is also why views in which universes continously
fork as events occur in one way or the other does not make
much sense for me.

> This list goes many times beyond the reductionist ways of thinking.

I don't think that the first view is beyond the reductionist
ways of thinking. Both views are compatible with a completely
mathematic (and even arithmetic) structure of the universe.

> Math logic is beyond models, it only becomes reductionistic, if applied to
> 'things/events': when limited models are quantitatively characterized in
> comparison with other models and an ( = ) sign (or similar) is applied to
> them within the selected boundaries.

Regards

Georges Quénot.

```