Re: Uniform access to descriptions

On Apr 9, 2008, at 9:34 AM, Pat Hayes wrote:
>> I don't know what 'essential characteristics' are. Really. What  
>> are the (erm...) characteristics of the 'essential  
>> characteristics' of some [named type of] thing? Who gets to decide?
>
> I'm reading 'essential characteristics' as meaning, roughly, what  
> in OntoClean are called 'rigid properties' and what are often  
> called 'essential properties', meaning properties or aspects of a  
> thing which it has necessarily, i.e. which if it didn't have those  
> it would cease to be what it is. Among my essential  
> characteristics, for example, is my being human; or if you prefer,  
> mammalian. And although we have the word "human" in English, its  
> impossible to convey the property of being human in a message.

OK, this is helpful, with the caveat that rigid properties are not  
absolute, but rather, an ontological choice. Formally they would  
depend on what range of possible worlds you allow.

I've always had a bit of problem working through thinking of them,  
though. How about this example from AWWW
> the resource is a periodically updated report on the weather in Oaxaca
>

What are the rigid properties here, and how are they communicated?

-Alan