Real taxa

[Richard Pyle]

> I was just arguing against the existence of self-made,
> or self-evident CLASSES out there, which was, I think,
> the topic of the thread... maybe I missed something.

Yes, I think this was (and still is) the topic.  To me, cases where the same
class is delineated the same way by two completely independent observers
suggest at least *some* self-evident "essence" of the class that transcends
human subjectivity.  Making this case for two groups of seeming independent
human observers is weak, because even though the two groups of humans may
have never directly communicated; both perceive the surrounding world in
very similar ways (same sensory systems, same metabolic needs, etc.). But
the idea of two separate and very different organisms (e.g., a human, a bee,
and a fungus), each with very different sensory systems and largely
different survival needs, "recognizing" (if not consciously so) virtually
identical classes in nature suggests to me that some inherent (self-evident)
aspect of the class unites members thereof in ways that go beyond subjective
human interpretation.  Maybe not as rigidly as the association between
helium molecules in different galaxies belonging intrinsically to the same
class of element (i.e., what we have labeled "helium") -- but at least it's
*some* indication of "reality".

> My point is that we shouldn't confuse "these organisms
> share a property" and "they are classified" in a taxon.
> A taxon is a concept, it does not exist out there. By definition.

Agreed.

> A fungus which develops on different substrates can help us seeking
> after and detecting a shared PROPERTY of these substrates. OK. And
> maybe some property of the fungus, by the way. Note that even
> properties are things we attribute to things.
>
> But this has nothing to do with fungi classifying things around them.

I guess it depends on what you mean by "classifying".

> I just contest the argument "fungi class organisms in species and genera",
> even "some way".

Well... in the simplest sense, fungi do (unconsciously) divide organisms
into two "classes":  those on which the fungus will grow, and those on which
the fungus will not grow. Yes, I agree, this is a function of the properties
of the host organisms -- but the point is, if the boundary of that
fungus-defined class coincides with the boundary of a human-defined class of
organism (at whatever rank), and the specific properties used by the fungus
are wholely independent of the properties use dby the human to define the
class (I say "wholely independent" to imply that the human did not use the
fact that a fungus will live on the organism as a primary factor in
establishing the human-defined class), then we can have increased confidence
that the class definition goes beyond mere human subjectivity.

Perhaps this is ultimately no different than a human using multiple
seemingly independent yet consilient sets of properties (e.g., molecular and
morphological) to add confidence to a taxonomic delineation; in which case I
agree it brings us no closer to some sort of "objective" reality of taxa.
Like I said earlier, I have to think about it some more.  But right now my
head hurts... :-)

> Richard's last message can help discussing further:
> briefly,
> - "nearly identical" classification is not identical classification.

Agreed! Which I guess brings us back to the original point of the
discussion.

> Phenetics and cladistics give the same tree for some simple data sets. And
so what?
> This is no argument.

Agreed.

> Instead, the differences are informative of the underlying different
criteria.
> - "living things can identify similar properties"... and thus
classifications?
> I don't think so. Some Pierid butterflies are trapped to lay on
flowerplants
> on which their caterpillars can't grow just because they "smell" some way
like
> cabbages, their correct host plant. Will botanist follow caterpillars for
> classification? I don't think so.

Good point! (Mimicry in general.)

> Moths also gather around street lights. What can we do with that?

This one is not so relevant, because the "photophilic" behavior is not about
a moth delimiting other organisms into classes.

> If even you decide to class according to fungi's "choices"
> (tropism in fact), it's still your decision, not fungi's one.

As noted above, the point is specifically not about using the fungi's
"classification" as a guide to creating human classifications.  The point is
about recognizing congruencies between pre-existing human- and
fungus-classification that did not directly (or indirectly) influence each
other. But the more I think about it, the more my head hurts.

> There is no way to escape facing our own classificatory decisions. Some
proponents
> of "natural-self-evident-classification" seem to try to emancipate from
this,
> which is impossible (in logics).

Agreed. (I think...)

Aloha,
Rich