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

[Brian Thomas]

	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.
	
	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
> 
>