# Re: Time

```Brent,

I'm not sure how the comment about real numbers effects my basic
argument. One interesting objection I got from someone not on this
list was that time isn't composed of moments at all, only intervals--
a "moment" is an imaginary thing that we get by considering
arbitrarily small intervals.```
```
Mathematically, though, a real-values time variable doesn't eliminate
moments, it just makes an infinite number of them between any other
two, with a particular mathematical structure. So the question of what
makes them "stick together" remains.

Obviously, one reason I think that I am traveling through time is
because I remember the past (but can only guess at the future). But
"remembering the past" is an experience that takes time, spanning many
moments, making this a little tangled. The multiverse complicates
things further: even supposing that only the possible worlds implied
by quantum mechanics exist (that is, no alternative physics, just all
possible quantum states) it is quite possible for me to remember the
future. It's merely improbable. But if all possible alternatives
actually occur, I don't know what probability means. (Even if there
are literally more alternatives down the probable paths, does this
make it more probable that I experience the more probable result? What
would that mean?)

--Abram

On Thu, Dec 18, 2008 at 7:21 PM, Brent Meeker <meeke...@dslextreme.com> wrote:
>
> Abram Demski wrote:
>> [Sorry if this is a duplicate, I think that I did not send correctly
>> the first time.]
>>
>> Bruno, everyone,
>>
>> I've decided that it will be more productive/entertaining to post my
>> various concerns as a new topic.
>>
>> What is time?
>>
>
> Time is what you read on a clock.
>> I'm going to ask a bunch of questions; for the sake of brevity, I'm
>> going to skip my arguments (which would mostly be reasons why
>> particular answers don't work). I'll argue once someone replies.
>>
>> If all possible universes exist, does that mean every possible moment,
>>
>
> What do you mean by "possible"?  Do you mean nomologically possible -
> which might be very restrictive but we don't know?  Or do you mean
> logically possible - just not instantiating a contradiction "X and
> not-X"?  Or something inbetween?
>
>> or every possible timeline of moments? If "moments" is the answer,
>> then how are the moments connected?
> If time is a real variable (which QM assumes), moments automatically
> inherit the topology of the reals.
>
>> How would it matter, since the
>> moments already are what they are? If "timeline" is the answer, then
>> there is a similar question of how it matters.
>>
>> If there is a physical universe, then is there some sort of basic
>> physical connection behind time?
>>
>> If the universe is mathematical in nature, then what is the
>> mathematical connection between moments? What sort of mathematical
>> connection counts as time?
>>
>> If (as was recently suggested, in connection with relativity) time
>> cannot really be divided into individual moments, then what is it?
>>
>
> In physics, it's a variable in the equations that determines the causal
> topology.
>> Why do we experience time passing?
>>
>> Is it legitimate to think as if the next moment we experience will be
>> chosen randomly in some sense? Does probability or randomness have a
>> role to play in the flow of time?
>>
> Randomness would seem to give a sense to the direction of time.  That's
> why physicist who are loathe to give up time-symmetry in their equations
> tend to favor Everett's interpretation of QM.
>
>> In connection with UDA: what is the meaning of a first-person
>> probability due to uncertainty of the future? Is there any sense in
>> which such estimates can be more or less accurate if all possible next
>> moments do in fact occur?
>>
> Good question.  It's the same as asking how the Born rule arises in
> Everett's interpretation of QM.
>
> Brent
>
>> Hope that sparks some thought...
>>
>> --
>> Abram Demski
>>
>> >
>>
>>
>
>
> >
>

--
Abram Demski

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