Re: Named graphs etc

On Mar 11, 2004, at 19:39, ext Pat Hayes wrote:

>
>> On Mar 10, 2004, at 15:09, ext Chris Bizer wrote:
>
> <snip>
>
>>
>>>>
>>>> Hmmm....  couldn't one view the insertion of graph qualification
>>>> statements specifying assertion and authentication as being
>>>> equivalent to a "speech act", the graph being the utterance?
>>>>
>>>
>>> Also hmmm ... and I think we should forward this question to Pat.
>
> See earlier message on 'web acts'. It does seem odd to me to say that 
> a graph can perform an act such as asserting. Suppose a graph slanders 
> me: can I sue the graph for damages? We have to get genuine agents 
> into the picture somehow.

No, no, no, Pat.

The graph is not being positied as a sentient entity.

Rather, the owner/creator/publisher of the graph uses special
vocabulary within statements in the graph to assert/sign the
graph -- in a way that such qualificatations can be authenticated
to a resonable degree.

By "self-asserting", I simply meant that the bits needed to
determine if a graph is asserted are in the graph.

I.e. "self documenting programming languages" do not mean
the code itself or the programming language is doing the
documenting, rather that the documentation is expressed
in some fashion native to the programming language and its
intended intepretation.

>
>>>
>>> 1. If "assertion = speech act", the assertion *has* to take place in 
>>> a
>>> "context" for example a point in time.
>>> Thus it is tempting to conclude that a graph is asserted, if it (1)
>>> describes itself
>>
>> I accept this.
>>
>>> or (2) is described somewhere else with the properties
>>> dc:author and dc:date.
>>
>> I don't accept this.
>>
>> This latter case is similar to one person saying what someone else
>> said -- i.e. hearsay. All that the first person could assert is
>> that the "speech act" occured and what its content was, but
>> can't assert the content of that speech act.
>
> No, it can. That is, it can assert ANY content. A says: "Im just 
> wanting to consider this as hypothetical: consider ...." Now, B can 
> agree with A (that ... is hypothetical) or, B can say "I think that 
> .... is true." No problem, B hasn't said that A said that .... is 
> true.

OK, I think I see where our disconnect is.

Yes, any graph can be taken to be asserted for a particular purpose,
and one agent can recommend to another agent that the graph should
be presumed to be asserted for a given application, etc. but that
is all about third-party assertion.

I am, and have been, talking about authoritative assertion. How do
we know if the owner/creator/publisher/original source of the graph
has asserted the graph, or whether they are just a bunch of statements?

Insofar as this latter question is concerned, I don't see one
graph specifying the assertiveness of another graph as practical.

>
>>
>> Restraining the boostrapping machinery to each graph prevents
>> folks from speaking on behalf of others.
>
> You don't speak on behalf of others by using their words to make an 
> assertion that they havn't made. If you SAY that they have made an 
> assertion that they havn't in fact made, or if you pretend to be them, 
> then you are lying: and we need to be able to check up on liars and 
> detect the lies quickly and reliably.

How? If the publisher of a graph says nothing about whether the graph
is asserted or not, how can anyone disagree with me if I say it is?

Having to rely on other (potentially infinite number of) other graphs
to determine the assertiveness of one particular graph seems to
introduce an horrifically inefficient and burdensome bootstrapping
mechanism.

Restricting the machinery to each specific graph alone, either by
some fancy semantics or by pushing it out to the syntactic layer
(i.e. XML attribute values, etc.) seems the only reasonable approach
to me.

The moment you have to start chasing chains of bootstrapping statements
in graph after graph to get a final determination regarding one
particular graph, is the moment you loose more folks now unsure about
deploying RDF.

KISS please!

>
>>> 2. Publishing an unasserted graph on the Web wouldn't be a speech 
>>> act.
>>
>> It wouldn't necessarily be.
>>
>> If no explicit statement is made within the graph that the graph
>> is asserted, then it is not (necessarily) a speech act.
>>
>> I.e. it is the act of using particular machinery to explicitly
>> indicate that a graph is asserted that constitutes the speech
>> act.
>>
>> If it were explicitly stated in the graph that the graph was
>> *not* asserted, then it would simply be a document (quoted
>> statements).
>>
>> Some agent may, for whatever reason, still wish to treat those
>> statements as asserted, but that is then contrary to the explicitly
>> expressed intended purpose of those statements by the publisher
>> of the graph (e.g. taking it out of context, etc.).
>>
>> Similar to my saying: "The following is false: 'sugar always tastes
>> bitter'" and you treating that as if I has actually asserted
>> that "sugar always tastes bitter".
>
> I bet what will happen is this (whatever we say about it :-) . There 
> will be a way to explicitly non-assert, like quoting; and there will 
> be a way to be absolutely and iron-clad clear about asserting and who 
> is doing the asserting, checkable by secure signatures.  And then 
> there will be cheap-and-cheerful publication which is not marked in 
> any way in particular but is widely accepted for many useful purposes 
> as being asserted as a kind of happy default that enables smart search 
> engines, etc., to get their stuff done when no serious $$ depends on 
> the result. What we need to do is to suggest how to do the former 
> without being so tight-assed that we try to legislate the latter out 
> of existence, because that would be like ordering the tide to stop 
> rising. I think that a way forward is to leave the status quo to do 
> the cheap-and-cheerful, but adding a way to be more secure in the 
> former style when required. To do that I think we need a way to 
> provide an external-to-RDF way to ultimately warrant the checkable 
> assertion forms, since that way of proceeding will almost certainly 
> require tort-law applicable ways of tracing the legal agents who are 
> making the iron-clad assertions (promises, contracts, etc.). And once 
> we have that, there is no harm in allowing 'external' assertion of 
> content, and quite a lot of utility in allowing it.


Um. Er. That is *precisely* what I have been proposing...

If no explicit statements are made about assertion, for legacy reasons
or out of sheer laziness, presume it is asserted (but keep at arms 
length,
per se, insofar as liability/accountability is concerned).

If there is an explicit statement that the graph is asserted, it's 
asserted.

If there is an explicit statement that the graph is not asserted, it's 
not asserted.

Seems like that is a pretty cheap-and-cheerful approach, yet one that
provides the key bits for authentication/trust/accountabililty for
those who care...

>
>>
>> --
>>
>> In essence, a graph explicitly marked as unasserted is a quoting
>> mechanism.
>
> Right. We could maybe do that, as Mark suggests, just by using the XML 
> media type (though that seems a bit kludgey to me.)

Yuck. And what about all the other serializations/expressions of RDF 
graphs? So we'd
end up with double the number of MIME types... no thanks.

>
>>
>> A graph with no explicit marking for assertion is simply an
>> ambiguous "utterance" which may or may not reflect the asserted
>> beliefs of the source.
>
> but which is good enough for many purposes, right? Particularly if 99% 
> of the RDF on the planet is deployed this way with the general 
> understanding that it is intended to be read and used.

Right. See above. Again, I'm talking about what is needed as a 
foundation
for authentication/trust/accountability, not whether any arbitrary set
of statements might or might not be useful for some application.

>
>>
>> A graph with explicit marking for assertion equates to an
>> utterance within a context of "I assert/swear/affirm/believe/...
>> that ...", which can serve as the basis for accountability
>> (and of course, trust).
>
> Right, but only if the thing doing the swearing and affirming is 
> something a bit more solid than a graph. It has to be the kind of 
> thing that a court can put a restraining order on, or you or I can 
> sue.

It *is*. That thing doing the assertion is the entity associated with a
signature or identified by a URI as the explicit authority, etc. I.e., 
if
I am asserting a graph, that signature and URI will ascribe those 
statements
to me.

Patrick

--

Patrick Stickler
Nokia, Finland
patrick.stickler@nokia.com

Received on Friday, 12 March 2004 03:49:36 UTC