Re: Assertional status of published information

>  > On Mar 09, 2004, at 07:11, ext Pat Hayes wrote:
>>  >> 1. Graphs published on the Semantic Web are not asserted
>>  >
>>  > Well, the trouble is that most folk think that they are being
>>  > asserted, at present. So we have to preserve this understanding of
>>  > current normal usage.
>Well, I don't know. Taking everything found on the Semantic Web as asserted
>seams like an invalid oversimplification to me.
>
>We are basically having the following situation on the Semantic Web:
>
>A information provider
>a) publishes information which he beliefs to be true, meaning he sees the
>information as asserted
>b) might want to publish information about which he isn't sure if it is true
>c) might want to publish information which he knows is wrong in order to
>achieve some advantage.
>d) might want to quote somebody, not assuming a shared conceptualization (de
>dicto)

I would prefer that we don't get into talking about belief. There 
will  be SW content published by software gents which probably can't 
even be said to have beliefs. Lets stick to speech acts: then the 
cases are

(a) publishes information and asserts that it is true
(b) publishes information without asserting that it is true, or with 
a qualified assertion
(c) like a, but this agent has nefarous purposes
(d) publishes text without asserting anything (except maybe that the 
text is what it is and other meta-infomation about it, which is 
handled like (a) )

I don't think we need to distinguish a from c, even if we were able 
to do so. Its not the SW's job to enforce honesty. So this just 
leaves a kind of spectrum of publication modes ranging from 
'asserted' to 'quoted' with maybe some 'qualifed assertion' types in 
between these (though Ive never seen any application area asking for 
these in-between cases, and kind of doubt they will be much practical 
use.)

>
>A information consumer
>- wants to use the published information for something (decision making
>...).
>- might have a different view of the world than the information provider.
>
>Which is exactly the situation we are facing in daily offline life. We don't
>take everything we hear as a fact, but evaluate if we belief it using the
>background knowledge we have. Thus I think that on the Semantic Web, it's
>also the job of the information consumer to decide which information we
>wants to treat as *asserted* and that a infrastructure supporting him should
>be open to a wide range of mechanisms for this decision.

I think we are talking at cross purposes. I agree that its up to the 
consumer to decide what to believe and what use to make of any 
information. But thats a different issue: I am talking about what the 
provider is doing. If A publishes some content and B reads it and 
makes use of it, can B come back to A and complain if it turns out to 
be false or misleading? If A has asserted it, then yes: if not, then 
no. B needs to know not just the content of C, but what A's stance 
was with respect to that content: was A asserting it, or merely 
reporting it, or intending to use it as the antecedent of a 
conditional, or even denying it or expressing doubt about it? None of 
this is visible in the normal semantics, which just give 
truth-conditions.

>Taking case a) and different world views between the information provider
>and consumer, we have a situation where a statement is asserted for the
>information provider but not for the information consumer.

That does not make sense. Asserting is a relationship between an 
agent and some content. Nobody expects a consumer to be doing any 
asserting (unless they are also a provider). Its like the distinction 
between putting up a notice and reading a notice. Asserting isn't 
done by the one who reads the notice, it is what gets the notice put 
there in the first place. The consumer is irrelevant: one can assert 
something even if there was nobody else on the planet to hear you 
assert it. I think you mean something like 'accepted by the 
consumer'. Sure, A might assert something and B may read it but not 
accept it. Happens all the time, not an issue. I don't think we need 
to even say anything special about it. Obviously a reader is not 
obliged to accept anything. Caveat lector.

>In case b) the
>information provider needs some mechanism to express that he isn't sure
>about the information (Statement about the graph within the graph or
>somewhere else).

that would be nice, but there are so many things one COULD do, that I 
would prefer to wait until it is clearer from actual use cases what 
it is that people feel that they want to do. The world needs to 
experiment some with this issue: we can't mandate how to handle it.

>In case c) the information consumer needs a trust mechanism to filter out
>wrong information.

But that is up to the consumer. I agree this will be important and I 
think it will become very complicated and in fact will become an 
entire economy, with lots of money to be made by people who can 
provide guarantees of trustworthiness of various kinds. Not our 
problem here, and far too big for us to tackle in any case.

>In case d) the information provider needs a mechanism to express the de
>dicto quotation, e.g. using literals.

I agree this would be very handy, and this case has already come up 
in practice many times. We need to be able to quote properly (ie not 
using reification). See my reply to Patrick for a simple suggestion.

>
>The question raised by Patrick if a information consumer can be held
>responsible for what he publishes is on a different level, which I think
>strictly requires digital signatures and PKIs.

I agree that the required technology gets into those issues, but I 
think we can reason about trust and responsibility and publication on 
a general level.

Pat

>Chris
>
>>
>>  True. It's probably most practical to allow folks to presume that unless
>>  explicitly stated that a graph is or isn't asserted, that it is
>>  asserted.
>>
>>  My recent proposal for a bootstrapping intra-graph vocabulary reflects
>>  the opposite
>>  presumption, that unless explicitly marked as asserted, it's not, but
>>  that's
>>  easily fixed.
>>
>>  Patrick
>>
>>  --
>>
>>  Patrick Stickler
>>  Nokia, Finland
>>  patrick.stickler@nokia.com
>>
>>
>>


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Received on Tuesday, 9 March 2004 11:48:23 UTC