Le 01-juin-05, à 18:49, Patrick Leahy a écrit :
>
> I read his book a year or so ago, so may be a bit hazy, but:
>
> Pour Bruno: he definitely does not want to talk about space-time
> capsules. Partly this is motivated by his metaphysical ideas about
> time, partly by the technicalities of the 3+1 (i.e. space+time, not
> persons!) approach to GR and the Wheeler-De Witt equation which he
> advocates. This leads him into severe difficulties, and he has not
> successfully described how this can be reconciled with the relativity
> of simultaneity, which he also wants to assert. Barbour regards this
> as an open question within his theory; others regard it as a fatal
> objection.
Thanks. Very clear.
>
> Of course when Barbour says that "time is an illusion" he really means
> that the *flow* of time is an illusion, or rather a category error,
> which is a pretty standard position (e.g. forcefully argued by Deutch
> in his book).
I agree with Deutsch. Note that I don't like to much the word
"illusion". A more relevant word would be phenomenological (but then
that's ugly). Perhaps "appearance" or "first person appearance" would
be more precise and less misleading than illusion.
> Although he sometimes speaks as though he denies it, I think if push
> came to shove he would have to admit that there is an identifiable,
> objective, structural feature in his (or anybody's) theory of physics
> which corresponds to time.
I hope for him!
Bruno
http://iridia.ulb.ac.be/~marchal/
Received on Thu Jun 02 2005 - 03:03:38 PDT