Le 12-mai-05, à 19:14, Peter D Jones a écrit :

I don't see why. Surely what is beng asserted is that there is a set of physically real universes, and it is a subset of logically possible universes ("Platonia") -- but logically possible universes are not real in any sense, they are just an abstrction.

`But logically possible universes are certainly real in one sense: as being logically possible. Or as being logically consistent.`

If they are furthermore enough rich in complexity to have "abstract inhabitant", it is reasonable or plausible (at least) that for those inhabitants their abstract universe will look as it is real. And this will make sense if, furthermore again, their relative abstract computational continuations have the right measure.

And theoretical computer science can justify the existence of such relative measure.

And, finally, if such mathematical measure leads to the verified empirical measure, then, frankly, it seems to me that materialism in physics begins to look like ... late vitalism in 19th century biology.

(And then my thesis shows that the mathematical measure extract from computer science looks sufficiently like the quantum measure to considerate that the case for a scientific materialism is at least premature.

If they are furthermore enough rich in complexity to have "abstract inhabitant", it is reasonable or plausible (at least) that for those inhabitants their abstract universe will look as it is real. And this will make sense if, furthermore again, their relative abstract computational continuations have the right measure.

And theoretical computer science can justify the existence of such relative measure.

And, finally, if such mathematical measure leads to the verified empirical measure, then, frankly, it seems to me that materialism in physics begins to look like ... late vitalism in 19th century biology.

(And then my thesis shows that the mathematical measure extract from computer science looks sufficiently like the quantum measure to considerate that the case for a scientific materialism is at least premature.

To sum up: "real" is just (abstract) consistency as seen from inside.

Bruno

http://iridia.ulb.ac.be/~marchal/