[Taxacom] Read... and believe...
s.thorpe at auckland.ac.nz
Sat Sep 5 01:12:42 CDT 2009
[Jim wrote] Not sure I entirely agree with you that an identification is an hypothesis. The taxon concept is the hypthesis and it can be tested and refined. The identification is an assertion; it is someting that just is. But it is all probably just a matter of semantics...
[reply] Not sure if that is just a matter of semantics. The (true) identity of a specimen is not a hypothesis, but an identification (=hypothesised identity) surely is? What I mean is that it is never 100% certain, and is vulnerable to falsification (or confirmation) given new information. A misidentification is a refuted identification.
[Jim wrote] When Homo/Pan/Pongo identifies a plant, HPP is making an assertion
that this plant has a sufficient number of attributes similar to another plant HPP has experienced to the extent that HPP is confident that it will also have the other attributes of the plant experienced earlier
[reply] not necessarily! When I identify an insect, in practical terms I am asserting that it falls within a certain range of variation which has a definite gap between it and anything else outside that range. My "hypothesis" may be refuted if I discover (too many) intermediates bridging that gap. Theoretically, I could do this just paying attention to a single attribute!
Analogy: I might be able to "identify" some people as "heavy people" or "light people", but there are too many intermediates for this to have any real meaning. But if all people of a certain intermediate weight class died out, it could be a perfectly fine classification - though not of course a taxonomic one. But it could be a taxonomic one. The taxonomic significance of a character is not evident a priori...
I guess I think that a proper understanding of the issues here depends on the way the world actually is, and so cannot be worked out a priori ...
From: Jim Croft [jim.croft at gmail.com]
Sent: Saturday, 5 September 2009 5:42 p.m.
To: Stephen Thorpe
Subject: Re: [Taxacom] Read... and believe...
*Everybody* knows about identification and what identification means.
It is what it means to be human and certainly predates Homo, Pan and
Pongo. But let's not go there. Please! :)
I do not think Roger's declaration you quote is theoretical, but it
certainly talking about abstraction.
When Homo/Pan/Pongo identifies a plant, HPP is making an assertion
that this plant has a sufficient number of attributes similar to
another plant HPP has experienced to the extent that HPP is confident
that it will also have the other attributes of the plant experienced
earlier. The fundamental survival and evolutionary imperative of
predictability - *that* is why HPP identifies.
The way it works is very simple. A HPP physically or conceptually
places the object in question with other objects a HPP considers or
asserts to be the same, noting or imagining boundaries around this
abstract concept or grouping of like objects. Then begins the
negotiations with other HPPs about what is in this this grouping or
concept, what is in another grouping or concept, and how will the
grouping or concept be labelled and communicated to other HPPs and
what might it mean should you chose to eat it or interact with it.
The Australia HISPID standard had an item for confidence of
identification, pretty close to what you list under (3) below. From
memory, its started form something like 'it is the type'! :)
Not sure I entirely agree with you that an identification is an
hypothesis. The taxon concept is the hypthesis and it can be tested
and refined. The identification is an assertion; it is someting that
just is. But it is all probably just a matter of semantics...
Yes, not all concepts are published, but they are the only ones you
can refer to with any degree of repeatability. The problem for
collections management, and especially for database management, is
that you can never be really sure what the prevailing 'concept' is or
was. It is never, or almost never, stated and is subconsciously
assumed, sometimes by contextual inference or implication, sometimes
by prior preference or prejudice.
Returning to a previous question on whether I considered pre Linnaean
to be 'better', in some respects it was. At least with the rambling
descriptive name you had some idea of what the user of the name had in
I have to say I am pleased and comforted by the increasing discussion
of the existence and role of 'taxon concepts' and the implications of
this for taxonomic information management and communications. I am
looking forward to the day when we can look back on all this and say,
'what was all that fuss about?'.
On Sat, Sep 5, 2009 at 12:08 PM, Stephen Thorpe<s.thorpe at auckland.ac.nz> wrote:
> Hi Jim,
> One thing I do know a thing or two about is diagnostics/identification, and what an identification "means". I have much practical experience and understanding of this area, because it is what I do (and have done nothing else for the last 10+ years). I have to laugh when I read things like the quote from Roger Hyam:
> If a specimen is named but the taxonomic classification used in the naming is not specified then it can’t be know which taxon (of the multiple possible taxon
> concepts for that name) it has been identified to
> Such quotes are way too naively "theoretical"! Taxonomic diagnostics just doesn't work like that in practice! So, how does it work? Let me try to being to suggest how:
> (1) An identification without indication of identifier/date is relatively (but not entirely) meaningless, and represents the least desirable situation. Even if an idiot identified something, it is better to know this than to not know the identifier!
> (2) Given sufficient experience and familiarity with a group, there is typically a very high level of agreement between competent identifiers on what the taxon boundaries are. The "gaps" between taxa are an empirical feature of the world. Luckily, we do not live in a world where every taxon merges into every other taxon! There are of course some problem cases.
> (3) At one stage I had thought of adding the basis for my identification to my identifications, something like:
> Examplus primus Smith, 1970, s.d. (=subsequentum descriptionibus =from original description)
> Examplus primus Smith, 1970, compared with type
> Examplus primus Smith, 1970, keyed in Jones (1980)
> Examplus primus Smith, 1970, as identified by Jones, 1975 (unpublished determination label)
> Examplus primus Smith, 1970, as identified (anonymously) in NZAC
> but it soon became apparent to me that I use a complex combination of things to identify a specimen, and it is not really possible, or necessary, to try to disentangle them all and explicitly state them. Most of the time, there would be no disagreement over the identification - all competent identifiers would agree ...
> An identification is a hypothesis, like any other
> Very often, there isn't anything that one could call a published taxon concept! There is just a vague original description, and hopefully a type specimen. It is the unpublished taxon concept of the identifier (which is likely to agree in most cases with that of other competent identifiers) which determines the meaning of the identification, which is why we want to know the identifier/date that goes with the identification.
> All of this creates a workable system, but perhaps not one that a machine could "understand" ...
> From: taxacom-bounces at mailman.nhm.ku.edu [taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Jim Croft [jim.croft at gmail.com]
> Sent: Saturday, 5 September 2009 5:23 a.m.
> To: TaxaCom
> Subject: [Taxacom] Read... and believe...
> you can weep if you like:
> a blog post by Roger Hyam: http://www.hyam.net/blog/archives/598
> For example:
> " 1. Names are not reliable pointers to taxa. If a specimen is named
> but the taxonomic classification used in the naming is not specified
> then it can’t be know which taxon (of the multiple possible taxon
> concepts for that name) it has been identified to. See Taxa, Taxon
> Names and Globally Unique Identifiers in Perspective.
> 2. Descriptions require human interpretation. As described above, the
> use of exemplar specimens combined with descriptions means that
> identifications will vary between experts.
> 3. Relationships between descriptions are vague. The same name may be
> used for several separately defined taxa. The descriptions of these
> taxa may use the same or different morphological characteristics. Some
> descriptions will omit characteristics used in other descriptions that
> are ostensibly about of the same taxon. It is therefore not possible
> to say whether the two description overlap, are equivalents or do not
> intersect at all."
> Jim Croft ~ jim.croft at gmail.com ~ +61-2-62509499 ~
> ... in pursuit of the meaning of leaf ...
> ... 'All is leaf' ('Alles ist Blatt') - Goethe
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Jim Croft ~ jim.croft at gmail.com ~ +61-2-62509499 ~
... in pursuit of the meaning of leaf ...
... 'All is leaf' ('Alles ist Blatt') - Goethe
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