Again, I agree generally with Bruce, but would like to add a bit more.=20
The purpose of making a definition is to capture an interesting or useful=
semantic distinction with a syntactic label. Ostensibly, it matters not=
what that label is, as long as it's distinct: correctly distinguishing the=
concept in question is the most important thing, and is a measure of the=
definition's meaningfullness. Note that the distinction can be more or less=
specific and precise.
A SECONDARY consideration (although still very important) is that the term=
used is coherent with the rest of the semantic web used by the linguistic=
community. Picking the RIGHT term for a concept is very much a political=
and rhetorical issue. This is what we usually are referring to when we=
derogate "semantic quibbling".
The overall quality of the definition will depend on all of these.=
Generally, specificity, precision, and coherence are valued in addition to =
meaningfullness.
So when they say:
>ENTROPY:
> A tendency towards disorder within a closed system, as potential ene=
rgy
> gets "spent".
this is in fact both a definition (A tendency towards disorder within a=
closed system), and a theoretical statement, that it involves spending=
potential energy. This is not a very specific definition, since it begs the=
meaning of "disorder", "closed", "system", and "tendency". Nor is it=
especially coherent with the linguistic community, although I should say=
that the linguistic community itself isn't all that coherent to begin with.
And when they say:
>FEEDBACK:
> "Any reciprocal flow of influence. In systems thinking it is an
>axiom that
> every influence is both cause and effect. Nothing is ever influenced
>in just
> one direction." (Fifth Discipline)
This is again a definition combined with a further characterization. The=
definition part itself is also highly nonspecific, and while it captures an=
interesting distcintion, it does so vaguely, and thus its meaningfullness=
is hard to judge. Coherence is also low, since feedback is usually=
considered a specific kind of circular causality, itself a specific kind of=
reciprocal influence. The last two sentences are simply highly questionable=
statements, not in fact definitions.
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->
| Cliff Joslyn, NRC Research Associate, Cybernetician at Large
| Mail Code 522.3, NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA
| joslyn@kong.gsfc.nasa.gov http://groucho.gsfc.nasa.gov/joslyn 301-286-2598
V All the world is biscuit-shaped. . .