[FOM] Could spacetime be discrete?

[Richard Haney]

"bcc" to Alasdair Urquhart urquhart at cs.toronto.edu

Alasdair Urquhart urquhart at cs.toronto.edu wrote:

<begin quote>
Richard Haney raises the question as to whether spacetime could be
discrete.  I am not sure what this means, but if it means that there is
a minimum length, this appear inconsistent with special relativity. 
Could somebody elucidate this point?
<end quote>

I think the idea was posed in the context of trying to find a better
alternative to the existing theories of (general, including special)
relativity and quantum mechanics, which are already contradictory to
each other.  Apparently, physicists frequently or usually assume an
"operational" or "instrumental" meaning of theories.  Basically, that
seems to mean in this case that there is no way to measure or detect
distances any finer than the theorized discrete space or to detect
particles any closer together than "adjacent" points of discrete space.
 But I suppose that those posing the ideas may possibly have had
alternative meanings in mind.   I suppose the idea may have been partly
motivated by the idea that if one is going to have only discrete energy
levels and only discrete quantities of various elementary-particle
properties, one may as well extend one's imagination to discrete
space-time as well.

Richard Haney


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