On the impossibility of defining anything whatsoever (as Rob might have you believe) (Was: Re: New issue?: vocabulary maintenance

[Alasdair Gray]

Brian,

I'm afraid I have a quibble.

Brian Thomas wrote:
> 	Ah Rob, 
>
> 	I knew as I was writting my email that you would respond and
> 	be positioned at the other side of the fence.
>
> 	Let me ask this simple question : if the definition of astronomy 
> 	concepts (or the concepts of any field) are in general  impossible
> 	as you seem to indicate, then how do any text books get written? 
> 	How does one write a dictionary? I note that these things exist, 
> 	and are generally accepted without the public rushing in on the
> 	offending author(s) with Frankenstein rakes and burning torches.
>
> 	We are not looking for "complete" definitions, but rather, simple,
> 	workaday ones which will serve the purpose of general identification
> 	of a subject/concept. At risk of further falling into a trap you have
> 	laid for me, I'll try a simple definition of gamma ray burst from
> 	the wikipedia:
>
> Gamma-ray bursts (GRBs) are the most luminous events occurring in the universe since the Big Bang. 
> They are flashes of gamma rays emanating from seemingly random places in deep space at random times. 
> The duration of a gamma-ray burst is typically a few seconds, but can range from a few milliseconds to 
> minutes, and the initial burst is usually followed by a longer-lived "afterglow" emitting at longer wavelengths
>  (X-ray, ultraviolet, optical, infrared, and radio). Gamma-ray bursts are detected by orbiting satellites 
> about two to three times per week, but their actual rate of occurrence is much higher because not all 
> bursts are pointed at Earth.
>   
This is somewhat long-winded for a definition in a vocabulary. Ideally 
we want a sentence or two to succinctly convey the idea of the concept 
without pinning down the definition too far that it is controversial.

Alasdair
> 	
> 	So...you would tell me that the above paragraph (easily obtained, I might add)
> 	is insufficient for a general definition of a GRB?!? 
>
> 	I would like to further add that if some people argue with this definition..
> 	so what? They may start their own vocabulary, -or-, they may engage
> 	us to either fix the definition or to evolve the vocabulary. Either recourse seems
> 	reasonable to me, and perfectly practicable.
>
> 	Regards,
>
> 	=brian
>
>
> On Wednesday 06 February 2008 11:13:54 am Rob Seaman wrote:
>   
>> Brian Thomas wrote:
>>
>>     
>>> On a population of 1000 terms, I was able to use the WordNet to  
>>> garner 800
>>>       
>>> or so definitions. From those, it had an overall accuracy (this is  
>>> from memory)
>>> of about 75% (in otherwords, about 75% of the time, the definition  
>>> looked
>>> fine with no editing).
>>>       
>> Definition is driven by usage.  The OED was assembled by a team who  
>> scoured every primary source they could get their hands on, writing  
>> examples of usage on innumerable scraps of paper.  Usage is also how  
>> the list of UCDs was compiled.
>>
>>     
>>> I image that we can create definitions which are "generally"  
>>> accurate and
>>> acceptable.
>>>       
>> Acceptable for what purpose(s)?
>>
>>     
>>> For the really controversial terms (and how many of these can
>>> there possibly be??)
>>>       
>> Consider even something as overtly obvious as "planet".  Many terms  
>> such as "universal time" have multiple conflicting definitions.  Are  
>> we signing on to convey the 150 different meanings of the word "set"?
>>
>>     
>>> we can provide pointers to 'seminal' papers =or= better
>>> yet, just drop any definition at all and save the argument for a  
>>> rainy day.
>>>       
>> Let's focus on compiling a list of terms first, their meanings later  
>> (or never).  Actually, an indication of the success of VO efforts will  
>> be when the larger community of astronomers regards it as unremarkable  
>> that they are using VO facilities to compile such definitions.
>>
>> What is the definition of a "gamma-ray burst", for instance?  Is it  
>> what the name says, a detected burst of celestial gamma-rays, meeting  
>> some threshold criteria of amplitude and time variability?  Or is it  
>> the underlying physical phenomenon - the engine driving the burst?   
>> Both, but especially the latter, are subject to definition and  
>> redefinition for as long as related phenomena remain an active area of  
>> study.
>>
>> In science, definition is also driven by theory and experiment.
>>
>> - Rob
>>
>>
>>