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RE: A Priori Information (Was Snapshot of Web Services Glossary )

From: David Orchard <dorchard@bea.com>
Date: Wed, 26 Feb 2003 21:58:47 -0800
To: "'Mahan Michael \(NRC/Boston\)'" <michael.mahan@nokia.com>, "'ext Cutler, Roger \(RogerCutler\)'" <RogerCutler@chevrontexaco.com>, "'Assaf Arkin'" <arkin@intalio.com>, "'Hugo Haas'" <hugo@w3.org>
Cc: "'David Booth'" <dbooth@w3.org>, <www-ws-arch@w3.org>, "'Mark Baker'" <distobj@acm.org>
Message-ID: <005101c2de25$4b5cbbc0$770ba8c0@beasys.com>

My big problem so far, and I haven't been able to wade through all the
emails to figure it out, is that I can't figure out what knowledge is
allowed to be in scope for non a priori.  For example, GETting a web page
requires a knowledge of HTTP, TCP/IP, URIs.  So is it knowledge of the
format of the representation?  Ah, but if I'm a browser, I certainly have to
"know" what HTML, JPEG, GIF, etc. are in order to render them properly.

My guess is that any discussion around a priori has to focus on what
knowledge classifies as a priori, and what doesn't.

Cheers,
Dave

> -----Original Message-----
> From: www-ws-arch-request@w3.org [mailto:www-ws-arch-request@w3.org]On
> Behalf Of Mahan Michael (NRC/Boston)
> Sent: Wednesday, February 26, 2003 2:08 PM
> To: ext Cutler, Roger (RogerCutler); Assaf Arkin; David Orchard; Hugo
> Haas
> Cc: David Booth; www-ws-arch@w3.org; Mark Baker
> Subject: Re: A Priori Information (Was Snapshot of Web
> Services Glossary
> )
>
>
>
> Roger,
>
> I believe 'a priori' and 'non a priori' are terms from the
> domain of agents
> and semantic web. 'Non a priori' means 'without prior
> knowledge' and is used
> to describe the property of an SW agent that can 'understand' what any
> deployed and ontologically described service does/means and
> how to invoke
> it, at runtime. In the context of AR023.7.1, this nuance is
> lost and so I
> would recommend making the word change in 23.7.1 to 'prior' and not
> bothering with the glossary.
>
> Mike Mahan, Nokia
>
>
> On 2/26/03 3:51 PM, "ext Cutler, Roger (RogerCutler)"
> <RogerCutler@ChevronTexaco.com> wrote:
>
> >
> > Geez, the WHOLE point of this is interpreting the phrase used in the
> > charter and requirements in order to answer a formal issue.
>  The issue
> > is what is meant when the phrase is used in the charter, and more or
> > less copied into the requirements -- not what the phrase
> means in some
> > general sense.  Is there any way we can found out who wrote
> the #$%%^#
> > thing and ask what the heck they had in mind?
> >
> > I remind you that even if we are thinking of the charter as
> governing
> > law, the courts consider the intention of the legislative body when
> > interpreting what a law means.  We don't exactly have to go
> back to the
> > Federalist Papers to do this.
> >
> > The change log of the Requirements Doc says something about
> "add Mark
> > B's a priori requirement ...".  Does Mark Baker have something to do
> > with the use of this phrase?  Mark Baker, in a posting
> 2/26, seems to
> > say that he agrees that the term "prior" should replace "a priori".
> >
> > Is there anyone who REALLY wants and cares about the use of
> "a priori"
> > as opposed to "prior" in the charter and the requirements?
> If not, can
> > we possibly declare this argument to be moot?
> >
> > -----Original Message-----
> > From: Assaf Arkin [mailto:arkin@intalio.com]
> > Sent: Wednesday, February 26, 2003 2:02 PM
> > To: Cutler, Roger (RogerCutler); David Orchard; Hugo Haas
> > Cc: David Booth; www-ws-arch@w3.org
> > Subject: RE: A Priori Information (Was Snapshot of Web
> Services Glossary
> > )
> >
> >
> >
> >
> >> -----Original Message-----
> >> From: www-ws-arch-request@w3.org
> [mailto:www-ws-arch-request@w3.org]On
> >> Behalf Of Cutler, Roger (RogerCutler)
> >> Sent: Wednesday, February 26, 2003 9:50 AM
> >> To: David Orchard; Hugo Haas
> >> Cc: David Booth; www-ws-arch@w3.org
> >> Subject: RE: A Priori Information (Was Snapshot of Web Services
> >> Glossary
> >> )
> >>
> >>
> >>
> >> I think that the term "a priori" really only has one
> rigorous meaning,
> >
> >> and that is (as posted by Ugo 2/19):
> >>
> >> A priori: relating to or derived by reasoning from self-evident
> >> propositions.
> >
> > That's one definition, but all the ones I've read [1] seem
> to imply that
> > a priori knowledge is one that is not based on facts, such as
> > self-evident, intuitive or whatever reasoning you had and want to
> > validate.
> >
> > So a use case would go like that:
> >
> > - I think this service will give me the time of day (a priori)
> > - I send a request, get a response, validate/invalidate my
> assumption
> >
> > So, to further confuse the reader, if I had a definition of
> the service
> > that I want to interact with, I would say that's a priori knowledge.
> > It's not self evident or intuitive, but it's reasoning based on the
> > service definition. It's not validated.
> >
> > I send a request, get a response, validate my assumption
> based on that
> > response and now my knowledge is no longer a priori.
> >
> > On the other hand, if I have an end-point with no idea what it does,
> > send a message and get some response back, then I learn
> what the service
> > does without a priori knowledge. (End-point is considered prior
> > knowledge in this
> > context)
> >
> > In other words, using a WSDL definition to interact with a
> service is a
> > priori knowledge, but just sending some empty message and getting a
> > response is no a priori knowledge with prior knowledge.
> >
> > And before REST advocates interject, the same holds true
> for protocol
> > listed in the URL. Assuming that a URL starting with http:
> implies an
> > HTTP server at that end is a priori knowledge. We validate
> it by sending
> > an HTTP request and seeing whether we get any HTTP response or some
> > other response (no HTTP server here, go away!) or no
> response (no TCP
> > server here, have a nice day).
> >
> > arkin
> >
> > [1] http://dictionary.reference.com/search?q=a+priori&r=3
> >
> >>
> >> However, as David has pointed out, the objective here is really to
> >> deal with the issue that has been raised.  We are, I believe,
> >> suggesting that we don't really have to define the term in the
> >> Glossary if we don't intend to use it in the architecture document,
> >> but we do have to deal with the issue.
> >>
> >> I think that the underlying assumption here, at least in
> my mind and I
> >
> >> think in a number of others, is that the term was used somewhat
> >> carelessly in the charter and that whoever wrote it really meant
> >> "prior".  The statement is much easier to understand if one
> >> substitutes "prior" for "a priori", and it seems to have a real
> >> function that way. That is, if we interpret it in this way we think
> >> that we are being consistent with, and responding to, the intended
> >> meaning of the charter. I think that if we get embroiled
> in a lengthy
> >> discussion of the term "a priori" we will, in fact, not be
> responding
> >> to the intent of the charter.
> >>
> >> At the very least, if we answer the issue in this way it
> puts the ball
> >
> >> in the other court.  That is, if the framers of the charter REALLY
> >> meant something other than "prior" they can tell us so,
> since we have
> >> made it very clear that this is our best understanding of what they
> >> meant at this moment.
> >>
> >> If we take this path, however, I think we definitely do NOT want to
> >> put a definition of "a priori" into the glossary that says it is
> >> equivalent to "prior".  That would simply be propagating confusion.
> >>
> >> -----Original Message-----
> >> From: David Orchard [mailto:dorchard@bea.com]
> >> Sent: Wednesday, February 26, 2003 10:47 AM
> >> To: Cutler, Roger (RogerCutler); 'Hugo Haas'
> >> Cc: 'David Booth'; www-ws-arch@w3.org
> >> Subject: RE: A Priori Information (Was Snapshot of Web Services
> >> Glossary
> >> )
> >>
> >>
> >> I dunno.  I think that the term "A priori" should be defined in a
> >> rigorous way.  Can somebody summarize the differences between the
> >> definitions that have been championed?
> >>
> >> Dave
> >>
> >>> -----Original Message-----
> >>> From: www-ws-arch-request@w3.org
> >>> [mailto:www-ws-arch-request@w3.org]On
> >>> Behalf Of Cutler, Roger (RogerCutler)
> >>> Sent: Wednesday, February 26, 2003 7:37 AM
> >>> To: Hugo Haas
> >>> Cc: David Booth; www-ws-arch@w3.org
> >>> Subject: RE: A Priori Information (Was Snapshot of Web
> >>> Services Glossary
> >>> )
> >>>
> >>>
> >>>
> >>> Well, the suggestion was NOT to put anything in the glossary for
> >>> this term and to use the verbiage below as a response to
> the issue.
> >>>
> >>> I'm not sure if we have anything explicit in the
> requirements about
> >>> supporting late binding, but it seems to me that a number
> of people
> >>> on
> >>
> >>> the WG consider this important and that this was the sense of the
> >>> statement in the charter.
> >>>
> >>> -----Original Message-----
> >>> From: Hugo Haas [mailto:hugo@w3.org]
> >>> Sent: Wednesday, February 26, 2003 9:34 AM
> >>> To: Cutler, Roger (RogerCutler)
> >>> Cc: David Booth; www-ws-arch@w3.org
> >>> Subject: Re: A Priori Information (Was Snapshot of Web Services
> >>> Glossary
> >>> )
> >>>
> >>>
> >>> * Cutler, Roger (RogerCutler) <RogerCutler@chevrontexaco.com>
> >>> [2003-02-24 10:41-0600]
> >>>> OK, we've kicked this term around enough so that it seems
> >>> pretty clear
> >>>
> >>>> that it is not going to be a quick kill to get consensus on
> >>> a general
> >>>> definition, and I think David is absolutely correct: we need to
> >>>> address the issue itself, but not necessarily this term as
> >>> a general
> >>>> concept.
> >>>>
> >>>> So I suggest something along the following resolution to resolve
> >>>> the
> >>>> issue:
> >>>>
> >>>> "The WG is not currently using the term "a priori
> >>> information" in the
> >>>> reference architecture, so we do not feel a need to come to an
> >>>> agreement about the meaning of the term in general.  In the
> >>> specific
> >>>> context in which it is used in the group charter, we
> >>> understand it to
> >>>> mean "prior information".  We interpret this as a
> >>> requirement that the
> >>>
> >>>> architecture support late binding."
> >>>
> >>> I am happy to put such a statement in the glossary.
> However, I think
> >
> >>> that we should add something (or a placeholder) in the WSA to talk
> >>> about it. Maybe just to say what you are saying here.
> >>>
> >>> However, I was wondering if we had actually a requirement
> about this
> >
> >>> before saying "We interpret this as a requirement that the
> >>> architecture support late binding."
> >>>
> >>> AC004 and AR004.2 read[1]:
> >>>
> >>> |   AC004
> >>> |          does not preclude any programming model.
> >>> |
> >>> |          + AR004.2 is comprised of loosely-coupled
> components and
> >>> their
> >>> |            interrelationships.
> >>>
> >>> I think that this is the one that has been discussed when
> there were
> >
> >>> late binding discussions, but I don't think that it explicitely
> >>> calls out for it. Maybe we are missing a requirement then.
> >>>
> >>> Or have I missed something in the requirements document?
> >>>
> >>> Regards,
> >>>
> >>> Hugo
> >>>
> >>>   1. http://www.w3.org/TR/2002/WD-wsa-reqs-20021114#AC004
> >>> --
> >>> Hugo Haas - W3C
> >>> mailto:hugo@w3.org - http://www.w3.org/People/Hugo/
> >>>
> >>>
> >>>
> >
> >
> >
> >
>
>
Received on Thursday, 27 February 2003 01:02:04 GMT

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