It's a fun way to put the question, Grant, > Should physics give up its similar insistence on verification (seeking "the > truth") - and join the ranks as just another branch of abstract mathematics?
(in context of your longer summary). One can almost do a meta-Popper on the relation of syntax to semantics of formal languages (or maybe the ur-Popper already did this, but the heathen in their sound-bites never get this far into his actual writing). A language that is not even internally consistent presumably has no hope of having an empirically valid semantics, since evidently the universe "is" something, and there is no semantic notion of ambiguity of its "being/not-being" some definite thing, structurally analogous to an inconsistent language's being able to arrive at a contradiction by taking two paths to answer a single proposition. However, a language that is internally consistent could still be empirically invalid. So here, "syntactically internally inconsistent" takes the place of Popper's "falsified", whereas "apparently syntactically internally consistent" takes the place of Popper's "not yet falsified". Trying to find a semantics for an apparently-consistent formal system takes the place of building empirical confidence in claims that in Popper's construction are still eligible to be "true". One then builds the commonly-discussed Popper-cum-Bayes notions of validity or invalidity of models as an analysis within the mapping of formal tokens to empirical events, predicated on the internal consistency of both the formal-token system and the empirical-event systems, each within itself. I think the argument that sustains the string theorists has a lot of this flavor. Most of the extrapolations one tries from the Standard Model of quantized gauge field theories (for matter) plus general relativity are demonstrably not consistent, so not even eligible for validation. The string theorists seem to still (believe they) have a construction that is not demonstrably inconsistent. To the extent that it has been hard to find any such construction, they hope to be lucky and have also found a valid one. Not surprising that the string theorists are in many ways hard to distinguish from mathematicians these days, and are among the first from physics in almost a century to have made contributions to hard problems in topology of manifolds. I did have to wonder, upon reading the Quanta article that was circulated, about whichever philosopher was claiming physics should give up long-held prejudices, such as that "quantum mechanics and gravity should be unified". I was curious what she thinks that combination of words means, that it could be given up: If you have gravitational contexts in which your efforts to do quantum field theory produce probabilities that do not sum to one, you have an internal contradiction within your formal language, and that means there must be a mistake somewhere. My understanding (though I cannot produce the argument myself) is that one cannot make a consistent quantum field theory with a non-quantum-mechanical gravitation dynamically coupled to it. To me, that was what the program of unification was about, much more fundamentally than whether quantum gauge fields were the appropriate formal language to include gravitation as well as matter. Eric > Grant > > > On 12/26/15 9:44 PM, Owen Densmore wrote: >> Abs fab! >> >> But amazingly, there are fantastic young grad students doing the impossible >> in this field .. testing at the Planck limits. Often using the universe >> itself to test its own theories. >> >> One of my favorites is a stream of matter flowing towards a void in space >> which suggests "gravity on the other side" .. i.e. a multiverse lump hidden >> from us but not by gravity. >> >> Why is there Something, not Nothing gets to be fascinating when the big bang >> was sparked by less than a tea-spoon of matter, or so it is thought nowadays. >> >> -- Owen >> >> On Sat, Dec 26, 2015 at 8:59 PM, Tom Johnson <[email protected]> wrote: >> Something to keep you occupied until New Years Day. >> >> https://www.quantamagazine.org/20151216-physicists-and-philosophers-debate-the-boundaries-of-science/ >> >> =================================== >> Tom Johnson - Inst. for Analytic Journalism >> Santa Fe, NM >> SPJ Region 9 Director >> [email protected] 505-473-9646 >> =================================== >> >> >> ============================================================ >> FRIAM Applied Complexity Group listserv >> Meets Fridays 9a-11:30 at cafe at St. John's College >> to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com >> >> >> >> ============================================================ >> FRIAM Applied Complexity Group listserv >> Meets Fridays 9a-11:30 at cafe at St. John's College >> to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com > > ============================================================ > FRIAM Applied Complexity Group listserv > Meets Fridays 9a-11:30 at cafe at St. John's College > to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com
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