# Three-taxon analysis

René Zaragüeta i Bagils rzb at MNHN.FR
Tue Apr 8 12:40:25 CDT 2003

```Dear P. Hovenkamp

"Apart from that, my point stands: if any of these proposed
mechanisms results in a particular pattern of sister-group relationships,
we may reasonably hope that we can find that pattern by studying the
characters of the taxa. Of course, many of these mechanisms will result in
very similar-looking patterns of relationship, and that is why there still
may be controversy and uncertainty"

We agree. Now you talk pattern. Mechanisms come after, this was what I tried
to say.

"When I was at secondary school, we used to amuse ourselves by proving
anything at all with series of impressive looking formula's, which on
closer inspection always included a division by zero somewhere. All this
elaborate reasoning strongly reminds me of that period. Once you start
misapplying terms you can "prove" anything. Characters cannot be
paraphyletic. The term does not apply. It is as simple as that."

Cladistic analysis is analysis, that means that what you know about the
whole is (no more that) what you know about the parts. The whole are taxa,
the parts are characters. These are no impressive formulae. If paraphyly
applies to taxa, it applies to characters, because taxa are composed of
characters (or cladistic analysis is not analysis).

"Never ask for certainty unless you can offer it. You can test the assertion
by looking for counterexamples. As you can any assertion."
I cannot give you any certainity. But your construction of multistate
characters uses certainty, at least that they are "states" of the "same"
character. I do not understand what do you mean by "counterexamples" in this
case.

"Can we make any observations at all? If you say
no, then retreat from science. If you say yes, you'd better start asking
yourself how we do it instead of simply trying to deny we can."
OK, it seems my English is really bad! The point is that the ultimate source
of knowledge are not observations. This is not my idea, but Karl Popper's.
You cannot learn anything from observations alone, you need a theory FIRST
to know what to observe (observations can only be tests of theories).

"Then solve those difficulties. You seem to accuse others of not doing the
things that you cannot do yourself. Go ahead. Solve the conceptual
difficulties of 3TA (some of them outlined above and in my other posts).
Solve the operational problems. At least make a start. There is nothing in
My english is perhaps still bad (I'm a foreigner living in France... I can
have language confusions). What I meant by difficulties was complexities.
But first, I do not accuse anybody, I ask questions and formulate
criticisms.
However, should you say that to, say, a physician? Solve the difficulties of
quantic mechanics! Solve the difficulties of relativity! Make operationnal
theory of black holes easy, and come back after! I don't think so.
Some thinks are just complex, and life is one of them, I'm sure you agree
with that. So the study of complex things is often complex.

RENE ZARAGUETA

```