From: SMTP%"phayes@cs.uiuc.edu" 8-MAR-1996 10:04:56.27 To: STAPP CC: Subj: Re: Reply to Hayes 5 Message-Id: <199603081800.MAA15949@tubman.ai.uiuc.edu> X-Sender: phayes@tubman.cs.uiuc.edu Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 8 Mar 1996 12:01:01 -0600 To: "Gregg Rosenberg" From: phayes@cs.uiuc.edu (Pat Hayes) Subject: Re: Reply to Hayes 5 Cc: klein@adage.Berkeley.EDU, A.Sloman@cs.bham.ac.uk, brings@rpi.edu, keith@imprint.co.uk, mckee@neosoft.com, patrickw@cs.monash.edu.au, STAPP@theorm.lbl.gov, phayes@cs.uiuc.edu >> >> Imagine someone in the 17th century objecting to the atomic hypothesis on >> the grounds that even if it were true, there would still be a 'hard >> problem' to 'bridge' between different 'aspects', because chalk was so, >> well, *chalky*, and clearly a collection of atoms, no matter how complex, >> wasn't going to ever be *chalky*. Seems to me that this case is almost >> exactly analogous. >> >> Pat > >These cases really are *almost* exactly analogous. They are analagous >in that the demand for proof is the same in both, and need to be met in >the same way: by evidencing an entailment (or convincing us that an >entailment exists in principle) from the properties a collection of atoms >would have to the chalkiness of the chalk. > >They are disanalagous in that such an entailment seems to exist (under >any ordinary understanding of what 'chalkiness' means) in the chalk >case. It does NOW. But I can imagine a philosopher still not being convinced: he might insist that all that had been demonstrated was a necessary correlation between the atomic structre and the chalkiness, but that nothing could ever bridge the conceptual gulf between *any* property derived in physical science and this 'chalkiness' business. At that point its best to quietly leave him alone, and get on with something more useful. Given the theoretical meanings of the terms in atomic chemistry, >a very good case can be made that one can derive precisely the reason >why chalk seems so chalky. It is interesting that you pick chalk as >your example: this is precisely the example that Steven Weinberg uses >(in Dreams of a Final Theory) to show *how* physics normally goes about >defending its explanations by producing entailments. Probably because we all have to use chalk every day ;-) > >In the phenomenal and functional case all we have (and it seems all we >could ever have) is correlation. We dont have the theory yet, but on what grounds (other than an extrapolation of a lack of imaginative insight into a claim of impossibility) can anyone state that this is all we could *ever* have? Pat PS thanks for the education, its been useful. One quibble: when you say that in order to provide an explanation, F must entail *all* of P, isnt that too strong? After all, that doesnt apply even in the ms/es case: the appearances are due to many factors (atmospheric, eg) as well as the characteritics of the planet Venus, but the identity was discovered long before we knew enough to completely draw all those entailments. If we allow the properties of P to be uncovered bit by bit, then I think we may already be making some progress. ---------------------------------------------------------------------- Beckman Institute (217)244 1616 office University of Illinois (217)328 3947 or (415)855 9043 home 405 North Mathews Avenue (217)244 8371 fax Urbana, IL. 61801 Phayes@ai.uiuc.edu ----------------------------------------------------------------------