nominal characters

Curtis Clark jcclark at CSUPOMONA.EDU
Fri Apr 7 08:55:23 CDT 1995

Date sent: 95.4.7
Renaud Fortuner wrote:
 >Curtis Clark said "It seems to me that
 >*any* two-state character is implicitly ordered" but there are in fact many
 >binary (2-states) characters that cannot be ordered, including all the
 >characters describing the presence/absence of a structure.

Presence = 1, absence = 0.  The distance from 1 to 0 is the same as the
distance from 0 to 1.  1 is greater than 0.  Thus the character is both
ordered and quantitative.  It still works if you code presence = 0
and absence = 1, or even presence = pi and absence = -(sqrt(2)). This
seems mathematically trivial to me, and the only reason I even mention
it is that whatever the point of all this discussion, claiming that
a binary character can ever not be ordered certainly obscures it for me.

On the other hand, if we are talking about ordered in the sense of
one following the other biologically, I think we're *all* barking
up the wrong tree.

Curtis Clark                                       Voice: (909) 869-4062
Biological Sciences Department                     FAX:   (909) 869-4396
California State Polytechnic University, Pomona
Pomona CA 91768-4032                               jcclark at

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