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Re: Working without being ambushed by Ambiguity (was: issue-57 background reading for F2F (short required reading)

From: Pat Hayes <phayes@ihmc.us>
Date: Tue, 23 Oct 2012 11:44:19 -0500
Cc: Tim Berners-Lee <timbl@w3.org>, Graham Klyne <GK@ninebynine.org>, David Booth <david@dbooth.org>, "www-tag@w3.org List" <www-tag@w3.org>
Message-Id: <8E6E98C2-E67F-47FB-843B-93E1D00F80F6@ihmc.us>
To: Larry Masinter <masinter@adobe.com>

On Oct 18, 2012, at 10:41 AM, Larry Masinter wrote:

> of the models you describe, none of them account well for the key elements of security, persistence, identity, provenance, uncertainty, belief and trust.
> Rather than putting those off as an afterthought to be worked out later, while failing to get a handle on a theory of meaning without them, they need to be central.

All of these rest on the basic notions of a name or identifier referring to something, and the truth of a proposition expressed by some sentence (or "contentful structure" of some kind.) We need to get the naming and the sentential structure clear before we can begin to make sense of ideas like provenance, belief or trust. 

> For example, the notion of "meaning" is tied completely to persistence.... a use of a URI is "cool" to the extent that its effect on recipients (its "meaning") doesn't change (over time or the range of recipients).

Wrong on several counts. First, this isn't what "meaning" means. If I assert that Everest is a mountain, what I mean is something about a place in Nepal, and mountains. I have no idea what a recipient is going to use this for or what effect it might have on them, and that has nothing to do with what I mean. (And this is just as well, since on the Web I cannot *possibly* know what effect it might have on them.) Second, meaning does not depend upon persistence. If my uncool URI changes its reference every week, then each week's meaning is perfectly clear (we can suppose) even though persistence is lacking. Weekly magazines might be good examples. Persistence might in fact be better defined in terms of reference and meaning rather than the other way around: for example, RDF and SPARQL have spend some time defining notions of equivalence which allow referents to change 'harmlessly' precisely because the *meaning* doesnt change. 

> As long as we talk about statements (triples) or terms (uris) having disembodied meaning or fail to take into account trust, error and malice, we're not making progress....  and wasting time. 

Until we do get "disembodied" meaning clear, we will never get out of the can of worms far enough to even get started on these harder problems. I agree they aren't afterthoughts, but they are thoughts that must come after. 


> --
> http://larry.masinter.net
> Tim Berners-Lee <timbl@w3.org> wrote:
> (I guess this is one of these things which is perennial.  I have not
> studied much of the history of philosophy but I do find one
> needs to be prepared to jump in in order to keep the  course
> of what I otherwise regard as engineering still on tracků
> as I have said before, this is philosophical engineering we are doing...)
> The point which David Booth has brought up, not for the
> first time, and which Pat has expounded very well, that 
> no symbol can ever have completely unambiguous meaning
> is, yes, quite valid.  There are several such points which
> we have to go over every now and again (preferably out of the critical path of
> working group work) and agree we all understand it and
> agree that we can all continue in practice without it.
> And indeed continue in theory without it as well.
> And Pat, you have lead us through that journey from 
> philosophical foundationlessness to logical foundations
> before and maybe you can help us again or just point
> to where you did before.  And Graham you make an
>  important distinction.
> There are lots of models, I am sure, one can make of
> ambiguity and language and communication which will
> allow us to do this, and they may differ in how they work
> and it probably is best that we agree they exist but not get 
> hung up arguing about which one is "right". They
> will all be imperfect, but good enough. 
> I have before and will now compare this with classical and 
> quantum physics.  We go through our young lives with 
> classical physics, and are taught that a billiard ball
> has a given diameter, a given mass, and a given position
> and a velocity, all of which we can measure.
> We learn how to build houses and drive cars
> all based on this physics. And then we get older and people
> tell us that actually a billiard ball does not have a well defined
> diameter.  Not only, if you look closely at it edge,
> is it a mass of atoms, but also those atoms in fact have only
> a probability of being in any one place at any one time.
> And even the billiard ball itself, if we measure its position too
> accurately in principle we can only do it by losing knowledge of
> its momentum.   Now the naively pedantic response may be to insist, that
> everything we learned in Classical Physics be
> thrown away.  This is the response which says
> that it is no use talking about the position of a ball anyway,
> as its atoms could in fact just randomly move 3 inches east 
> at the same time.  So it is that those who see that 
> in a deep enough analysis almost given term admits of ambiguity
> might say that the Architecture of the WWW" is useless as
> it says URIs should only be used to denote one thing.
> But in fact we really need to use the physics we have learned.
> We need to keep all we know about the way billiard balls
> interact at human scale.  Even though we have to be aware of
> quantum effects every now and again, when we find light
> being diffracted through a grating instead of being scattered,
> or electrons tunneling though a thin layer,
> we have ways of going into the details of the quantum effects
> where appropriate, and interfacing that thinking with the 
> classical thinking.  So it is with denotation by names.  We need to 
> keep the models of ambiguity in our back pocket  and
> bring them out when we need them, but not use them
> to ambush any discussion in the classical form.
> We should not use them to suggest that any use of the idea of a name
> having something it denotes is to be thrown away.
> Ok, so in physics there is maths which allows you to show that 
> in the large scale, the quantum model of the world in fact gives
> rise, to a very high degree of approximation, to the classic model.
> So now how do we construct a practical ability to use
> terms like the thing that a string denotes from the morass 
> of ambiguity which is communication?
> There are a number of models, none of which is perfect.
> What have we?
> 1) The Authoritative Dictionary model.  The guy who puts together
> the Oxford English Dictionary just knows more than anyone else 
> about how people use words, and we all make sure we use words
> just as they are described there.  If we don't find a use in it we want,
> we sent him a note.
> (This is perhaps the model we have in kindergarden)
> 2) The naive "meaning as use" model, sometimes blamed on Wittgenstein. 
> You use terms however you like, as meaning is use, and so you can never be using them inconsistently with their meaning.
> (Sometimes this may be -- who knows -- a response to realizing that the model 1 is not perfect)
> 3) The Expertise model.  The OED applies as above, but
> also we send lawyers to school for several years to agree on a set
> of terms which are more closely defined so we can use them
> in cases where we need unambiguity, like in contracts.
> To know what something means, ask a lawyer and if necessary 
> go to court to add enough extra definition to be able to continue.
> Pat describes some of the great lengths to which lawyers sometimes
> have to go 
> 4) The Areas of Expertise model. As above, but add in 
> groups of people with expertise in given areas. 
> Ask them to write anything you need in that area, and in 
> court  bring them in as expert witnesses.
> 5) The Standards Committee model.
> A committee writes a standard for use in a particular area
> writes it using a mixture of words which it feels are well enough
> defined in models 1 2 or 3, and terms which it defines
> specifically locally for its own use within the standard specification.
> It discusses and ruminates until it feels it has found a set
> or terms which are all mutually well defined and tight enough
> to make a standard which people will use without undesirable
> consequence through misunderstanding. (Not a standard
> which everyone will understand unambiguously in exactly the same way, note).
> (From time to time, the group may share its work with others
> and be horrified to find it has in the now larger community involved
> go through much longer discussion and rumination.)
> There is recourse in that others can, while the group is extant
> in some form, challenge it to resolve perceived ambiguities in
> the terms it uses or the things it writes.
> A common facet of all these models is that they 
> do not give complete unambiguity at all, just a good enough 
> definition.  "Good enough for government work" as they saying goes.
> Where "government work" is defined within some community
> of some size (See http://www.w3.org/DesignIssues/Fractal).
> We can continue listing these sorts of models.
> More importantly, we can engineer them.
> The initial philosophers seemed to treat language as a
> natural or god-made thing to be investigated not
> engineered invented things,
> but in fact dictionaries and court procedure and standards bodies
> are all engineered systems.  So we can design the ones we need.
> We therefore can improve on these systems,
> and, given that there is so much violence and counter productivity
> in the world and that much of it one might imagines stems from
> misunderstandings of some sort, it may behoove use to improve 
> on them.  That said, lets talk about this for URIs and
> specifically the Semantic Web design.
> The Semantic Web meta model.
> In a way the semantic web out-metas the model question.
> By focussing on the interchange of data in a restricted
> normal form, it can treat mathematically the systems 
> above -- and other systems -- in a logical way impossible
> with natural language terms.
> The semantic web itself is a design, not a philosophical observation
> about how language works anywhere else. 
> It decrees that there should be terms defined in the 
> http: URI space, and decrees that the DNS
> be part of a system of delegation of Ownership  
> of each term.  (I'm not going to quibble here about 
> whether ownership of terms delegated within domains)
> By realizing that there are many communities of people
> using all sorts of combination, and allowing people
> to create new terms very easily and being able to 
> avoid re-use of the same string,  it allows us to set up
> a system where the participating parties agree
> - The DNS, and further systems within many domain's http spaces,
> allow a social entity to allocate a name in HTTP space.
> That social entity is deemed the "Owner" of the name.
> Ownership is defined 
> - The network and the HTTP allows a machine to look up
> the name and get information back
> - This information you get back provides elucidation in two forms,
> in natural language (with various models of ambiguity relief)
> and logic (where the core terms such as the syntax of turtle,
> and rdf:type are defined in mode 5 by the W3C working groups
> etc).
> Everyone who uses the semantic web has to then sign
> up to this meta-model, though they can pick and chose 
> models above.
> Importantly, implicit or explicit in the information which is 
> returned is information about which mode is used 
> to relieve ambiguity.
> So the crucial design, then, is that when one agent sends
> another a message, that agent will pick a set of 
> terms which have different owners who operate or curate
> different vocabularies using different models above or 
> indeed combination of models and new models.
> The vocabularies are picked so that the disambiguation
> is good enough.   Good enough for the situation,
> for the sending and receiving agent.
> (We tend to call the information which we get back over HTTP
> the definition of the term. Well, we would except that we 
> would be ambushed by people who want to use the word
> "definition" specifically for a definition using one or other
> particular model).
> Of course in parallel with the actual looking up 
> of stuff on the web, also people share understandings
> over beers in bars as they always have done,
> but the semantic web linked data system is cool in two ways:
> Firstly, it instantiates the models of disambiguation
> providing a way to "look up the meaning" of something
> without having to have a notion that meaning is unambiguous.
> Secondly, it gives us the ability to write programs to help us,
> because of the logic interchanged. That's really handy.
> Now we have to, mainly, get on with the business of
> building systems, but we have to be aware of when the ambiguity
> case arises.  We need, in our discussions, to have things
> to point people to so that naive pedantic arguments don't
> derail perfectly good discussion and logic based on the idea that 
> names denote things.  But we need to be aware
> of when the pedantry is appropriate, and have avenues
> ready to go down.
> Example 1.
> In our semantic web based world,
> When you are using a form, you may fill in details
> about, say, a seminar you are organizing, and generally
> the prompts on the form allow you to fill in things
> like "Date", "Start time" and "End time" without likely
> damage due to misunderstanding.
> If you have to choose in a pull-down menu whether to categorize it
> as a talk or a class or a seminar or a concert, you might
> be more puzzled, but a good app will pull in comments
> from the ontology when you hover over it uncertainly,
> giving you enough more detailed information to make
> your decision. You can maybe even clock off and follow
> a link to bring up the detailed information from the ontology,
> and also you can search for members of each subclass,
> to see what existing things have been categorized each way and do on.
> So a user can well use the meaning lookup system,
> resolve the meaning well enough.
> Example 2
> Consider now the person who is creating the form.
> Each time they add a field, they will hopefully pick 
> an associated property for it.  And hopefully they 
> will pick a property from an existing ontology which 
> will give it wide interoperability.  You want the events defined by users of the form  to appear on people's calendars, for example,
> and feeds of upcoming talks.
> So at this point the user as form creator is
> more aware of the different organizations, and the different
> disambiguation models, which apply to each.
> The user will at this point quite likely pick a number
> very standard terms, a few from other ontologies,
> and then be stuck and have to make up a few properties.
> This is when the system needs ideally to be able to 
> give the user a feel for the cost of
> getting others to agree on the ontology, of keeping it up.
> This is where there should be buttons to invite comments
> and buttons to form a group, an buttons to to allow
> one to ask another group to collaborate, and so on.
> And depending on the sort of group formed
> and the sorts of groups to be collaborated with, 
> the social processes will be of all kinds.
> End of examples.
> So we can build systems which instantiate 
> and enhance the social processes which 
> we use to resolve ambiguity.
> So yes there many times when all the details of the
> way the semantic web resolves ambiguity enough
> for us to be able to talk about names having a single
> thing they denote, and even having a definition.
> And we understand the extent to
> which that breaks and where it affects us and we
> have a task of creating systems (technical and social)
> which behave appropriately and allow us to agree
> enough on the meaning of old terms and new ones
> to be able to collaborate better and better.
> But right now these social systems are in place in various forms
> so we need not be ambushed by the many rat-holes
> around this, some of which need to be charted and left rarely visited.
> Tim
> * "God created the Counting Numbers, and man invented the rest" -- @@@? 
> ** We don't want to send all the naive pedantic arguments off
> on the B ark, and then die from an unsanitized telephone.

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Received on Tuesday, 23 October 2012 16:44:53 UTC

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