[Taxacom] Clade age

Richard Jensen rjensen at saintmarys.edu
Mon Nov 14 14:35:13 CST 2011

> I only used science as an example, but you are, of course, right: it 
> is a human construct and requires a definition.
> I disagree with the idea that species names are merely diagnoses.  
> Species names are connotative, just as Linnaeus suggested.  And, as I 
> argued in my paper in Cladistics, species names are not proper names, 
> as the latter are commonly defined.  Species are natural constructs 
> and can be defined by possession of certain properties, whether these 
> be phenotypic traits or evolutionary origins.  Just as "triangle" is a 
> shorthand expression for a two-dimensional construct defined by a 
> given set of attributes,  "Homo sapiens" is a shorthand expression for 
> a natural entity defined by a given set of attributes.
> Cheers,
> Dick
> On 11/14/2011 1:03 PM, Curtis Clark wrote:
>> On 11/14/2011 8:40 AM, Richard Jensen wrote:
>>> Unfortunately, the one thing you and John agree on is a mistake.
>>> Definitions do matter.  They are essential for understandable
>>> communication.  If you are allowed to define "science" by your 
>>> criteria,
>>> and I am allowed to define it by a different set of properties, then 
>>> how
>>> can we ever communicate effectively?
>> Science is a human construct, and of course needs to be defined for 
>> effective discourse.
>> Many of us consider "carbon" to be a natural entity that exists 
>> independent of human perception. We could define it as all atoms with 
>> six protons, and as a "working definition", that's fine, but it's 
>> really a diagnosis, a summarization of a consistent observation.
>> Many of us consider "species" to be natural groupings of organisms 
>> that exist independent of human perception. It has been a while since 
>> scientists tried to define individual species (Linnaeus was one of 
>> the last famous examples), but people still try to define the 
>> "species concept". It seems to me a diagnosis is again the best 
>> approach: what are the commonalities of the entities we call species? 
>> Any single species "definition" will invariably leave out an entity 
>> that some group of competent biologists calls a species. And by 
>> defining "species", we end up knowing only what we know about it, 
>> without an easy route to learning more.
>>> John has made this argument before and it appears to be part of the
>>> problem in communicating with him.  His definitions often are quite
>>> different from those that many (most!) of us use and that only 
>>> serves to
>>> create confusion and a lot of unnecessary exchanges on Taxacom.
>> John plays fast and loose with definitions of human constructs. I 
>> agree that this impedes communication, and I have called him out on 
>> it. But to me this is quite different from defining or refusing to 
>> define observed entities in nature.

Curtis Clark http://www.csupomona.edu/~jcclark/
Professor, Biological Sciences                   +1 909 979 6371

Richard J. Jensen, Professor
Department of Biology
Saint Mary's College
Notre Dame, IN 46556
Tel: 574-284-4674

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