meekerdb wrote:
On 5/13/2015 5:32 PM, Russell Standish wrote:
On Thu, May 14, 2015 at 11:26:17AM +1200, LizR wrote:
On 13 May 2015 at 18:20, Russell Standish <[email protected]> wrote:
For a robust ontology, counterfactuals are physically instantiated,
therefore the MGA is invalid.
Can you elaborate on this? ISTM that counterfactuals aren't, and indeed
can't, be physically instantiated. (Isn't that what being counterfactual
means?!)
No - counterfactual just means not in this universe. If its not in any
universe, then its not just counterfactual, but actually illogical, or
impossible, or something.
If "not in any universe" is meant in the Kripke sense, then something
not in any universe is something that is logically impossible. But if
"not in any universe" is meant in the MWI sense, then counterfactuals
are only those outcomes consistent with QM but which don't happen. I
think it is only the latter kind of counterfactual that need be
considered in computations.
No. The counterfactuals that Bruno refers to in comp seem to come from
the "If A the B else C" construction of computer programming. This puts
no restriction on the worlds containg B and C. So it actually has
nothing whatsoever to do with MWI. As you say, the possible alternative
worlds in MWI come from the eigenfunctions of an eigenselected basis,
and those are by no means arbitrary.
Bruce
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.
