Re: KIM 2.3 (was Re: Time)

From: Bruno Marchal <marchal.domain.name.hidden>
Date: Tue, 6 Jan 2009 12:51:03 +0100

Abram,

I agree with Brent. In relativity theory space and time are
intermingled in a geometrical way to give the Minkowski structure.
Actually you can make it into an Euclidian space by introducing an
imaginary time t' = sqr(-1)*t = it. The metrics becomes dx^2 + dy^2 +
dz^2 + dt'^2.
In quantum mechanics the possible position of an object on a line gives
rise to an hermitian space: it is infinite dimensional, but there is
still a geometrical structure, with notions akin to angles and
distances. Of course mathematician have far more general notion of
dimensional spaces, some of which have nothing to do with geometry. In
physics metrics play always some role somewhere though.

Bruno


Le 06-janv.-09, à 02:59, Brent Meeker a écrit :

>
> Abram Demski wrote:
>> Thomas,
>>
>> If time is merely an additional space dimension, why do we experience
>> "moving" in it always and only in one direction? Why do we remember
>> the past and not the future? Could a being move in some spatial
>> dimension in the same way we move through time, and in doing so treat
>> time more like we treat space? Et cetera.
>>
>> To my knowledge, modern physics treats many things as "dimensions":
>> not just time and space, but also forces such as electromagnetism.
>> This does not imply that such things are spatial in nature. A
>> dimension is just a variable. Unless you think there is something
>> particularly spatial about time?
>
> There is something spatial about time, duration is measured along
> paths in
> space. Coordinate time is mixed with space by Lorentz symmetries.
> But it's
> still different from space. Lee Smolin and Fotini Markopolo have
> argued that
> time must be considered fundamental (no block universe).
>
> Brent
>
>
> >
>
http://iridia.ulb.ac.be/~marchal/


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Received on Tue Jan 06 2009 - 06:51:58 PST

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