Re: Tuple Store, Artificial Science, Cognitive Science and RDF (Re: What is a Knowledge Graph? CORRECTION)

The discussion could be more appropriate for the ai-kr list. Paola, how 
would you feel about continuing there?

Patrick J Hayes wrote:
> OK, I think this discussion is going beyond what is appropriate for 
> this forum, so if you want to continue, lets take this off-list, OK?
>
>> On Jun 26, 2019, at 9:50 AM, Dave Raggett <dsr@w3.org 
>> <mailto:dsr@w3.org>> wrote:
>>
>>
>>
>>> On 26 Jun 2019, at 16:24, Patrick J Hayes <phayes@ihmc.us 
>>> <mailto:phayes@ihmc.us>> wrote:
>>>
>>> A quick remark:
>>>
>>>> On Jun 26, 2019, at 8:03 AM, Dave Raggett <dsr@w3.org 
>>>> <mailto:dsr@w3.org>> wrote:
>>>>
>>>> I very much agree and have been arguing for a blend of symbolic and 
>>>> statistical techniques using insights from decades of work in 
>>>> Cognitive Psychology.  Rational belief is about what can be 
>>>> justified given prior knowledge and past experience.
>>>
>>> So far in this thread we have been talking about knowledge 
>>> representation notations. You are here talking about mechanisms, not 
>>> quite the same topic. I entirely agree about the need to put 
>>> together symbolic and statistical, but I don’t see any reason why 
>>> the use of the statistical would change the nature or the semantics 
>>> of the symbolic. (Do you?) 
>>
>> Good question. Statistical approaches alter the nature of reasoning, 
>> and this will influence the semantics.
>
> I don’t see why it would alter it. Take a simple example, say a 
> statement like ‘Capital cities are financial centers’, which might get 
> rendered as something like (forall (x)(if (CapitalCity x) 
> (FInancialCenter x))). Statistical tests of this assertion might 
> inolve counting the numbers of examples of CapitalCity and working out 
> percentages and so on. They might cause one to adjust confidence 
> levels for such a claim, or even to modify it in some way, perhaps by 
> inventing a new category of FinancialCapitalCity. But none of this 
> kind of arithmetic would alter the /meaning/ of “CapitalCity” or 
> “FinancialCenter”. In what way would you expect that /semantics/ would 
> change because statistical methods were applied?
>
>>>> This is not infallible, but nonetheless very useful in practice. It 
>>>> can support higher order reasoning, something that is essential for 
>>>> modelling human reasoning. 
>>>
>>> What kind of higher-order reasoning are you referring to here? The 
>>> term ‘higher-order’ has various meanings. If you simply mean that 
>>> the logic can mention, describe and quantify over properties and 
>>> relationships as first-class entities, then I would agree; but 
>>> versions of FOL, even RDF, can do that. 
>>
>> You will need to explain further. 
>
> If you want more details of how an essentially FO language can 
> describe relations, an old paper gives the basic idea: 
> https://pdfs.semanticscholar.org/d061/e6667716fec03325e586fe3020134d45a058.pdf?_ga=2.85123801.1565722984.1561617498-676702878.1561363073
>
> You might also find this useful, and the links in there to other 
> expositions:
> http://www.jfsowa.com/talks/clintro.pdf
>
>> Reification allows RDF to describe relationships, e.g. the time 
>> interval that a given relationship holds, 
>
> This is a common claim, but it is false. Reification allows RDF to 
> describe /RDF triples/, not relationships. RDF can already describe 
> relationships (‘properties’ in RDF-jargon) without using reification: 
> there are many examples in the RDFS axioms.
>
> Relationships in RDF (and logics in general) do not hold for times: 
> they are timeless. To describe temporally limited relations, one adds 
> the time as an extra parameter or argument ot the relation. (Or at any 
> rate that is one way to do it; there are others. There is a survey in 
> section 2 of 
> http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.529.5189&rep=rep1&type=pdf 
> <http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.529.5189&rep=rep1&type=pdf>, 
> which covers some of the common methods.)
>
>> but reification is painful in practice.
>
> No argument from me there. RDF reification should have been strangled 
> at birth.
>
>> Extensions to Turtle and to N3 have been proposed that makes this 
>> less painful to express and process. We also want to explore ideas 
>> for fresh representations of declarative knowledge and procedural 
>> rules that are easier for the average developer.
>>
>> We would like to be able to model the meaning of natural language in 
>> a way that mimics what we know about human reasoning 
>
> Well, that is a hugely ambitious goal. I wonder if you have any idea 
> of the scope of this ambition and how much work has already been done 
> towards it in AI, linguistics and cognitive science. (By the way, what 
> do you think we DO know about human reasoning?)
>
>> without reducing everything to logic.
>
> ? Why do you say /reducing/? Do you know of any other notation which 
> is richer or more expressive than FOL?  Have you looked at how logics 
> have actually been used to express complex knowledge about real 
> topics, such as the OBO foundry or the Cyc knowledge base, or ISO 
> 15926-2 <http://15926.org/topics/data-model/index.htm> andISO 15926-4 
> <http://15926.org/topics/reference-data/index.htm>? Have you read 
> Carnap’s “Logical Structure of the World”, or studied any of the many 
> published upper-level ontologies? Have you looked at Montague 
> semantics for natural language, or any of the other linguistic ideas 
> along these lines? Have you looked at AI work on NL comprehension and 
> how systems such as Allen’s TRIPS represent meanings? I do not know of 
> any serious work on linguistic meaning which does not use something at 
> least as expressive as FO logic as its meaning representation.
>
>> The semantics are defined operationally in terms of the application 
>> of rules on graphs, including the means to compile graphs to rules. 
>
> With respect, this is not a semantics. Nor will any such approach ever 
> succeed in capturing more than a tiny fragment of natural meaning. But 
> good luck trying.
>
>> Natural language is very flexible in its expressivity. 
>
> Again, no argument from me there.
>
> Best wishes
>
> Pat Hayes
>>
>> Dave Raggett <dsr@w3.org 
>> <mailto:dsr@w3.org>>http://www.w3.org/People/Raggett
>> W3C Data Activity Lead & W3C champion for the Web of things 
>

-- 
Regards

Chris
++++

Chief Executive, Lacibus <https://lacibus.net> Ltd
chris@lacibus.net