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Re: Philosophy (was Re: Cladistics)



In a message dated 98-02-24 14:57:46 EST, th81@umail.umd.edu writes:

<< In fact, many philosophers of science would argue that it is the mystic who
 can assert that they find the truth.  Scientists are limited only to
 approximations of the truth, potentially falsifiable on the basis of
 additional data.
 
 To give an example, what is the absolute true answer to the shape of the
 Earth?  This is a nice, scientific question, as it asks for a geometric
 description of a particular object.
 
 Is it a plane?  A cube?  A sphere?  An oblate spheroid?  All these are
 closer and closer approximations of the true surface, but none (even the
 last) is the TRUE answer, as even that one fails to account for differences
 in continental, regional, and local topography.  (And then, of course, there
 would be the question regarding the local sea and land fall due to tides,
 changes in shorelines, rise and fall of mountain ranges, etc., etc., etc.).
 
 Because the oblate spheroid model is the Truth doesn't mean that it is not
 useful.  Just because it isn't the Truth doesn't mean that it is less useful
 than the spherical, cubic, or planar models.  (To paraphrase Isaac Asimov,
 as I've been doing here, just because two models are "wrong" doesn't mean
 that they are both equally "wrong"). >>

The best answer to this question is that the earth doesn't have a shape in the
mathematical sense. It is an assemblage of atoms whose individual shapes can
only be described statistically.

Thus it is reasonable to maintain only that the earth has a particular shape
>to within any desired degree of accuracy<. This is the Truth of the situation
that we seek. The earth is not a cube to any degree of accuracy, nor is it a
plane. These answers are just plain wrong. The earth has a spherical shape to
an accuracy of about 97%, and an oblate spheroid to an accuracy of about
99.9%. Thereafter the shape becomes more complicated, since we have to include
mountain ranges, continents, and so forth, as you note.

So asking the question, "What is the shape of the earth?" is asking a question
that has no answer without qualifiers. When you add in the appropriate
qualifiers--that is, ask the right questions--then you do indeed get the
Truth. Truth is attainable, but >unqualified< Truth probably (heh heh) doesn't
exist and is meaningless to search for.

<<On the other hand, for some questions of particularly limited scope, it is
possible to set up the problem so that one (and only one) solution is
potentially correct.  Either fossil specimen A shared a more recent common
ancestor with fossil specimen B than it did with C, or B and C shared a more
recent common ancestor, or they all split off simultaneously from the same
ancestor.  There are only these three possibilities.  Only one of them could
be correct.

However, we can only reconstruct these events: they are gone now.  We might
have some model (parsimony, maximum likelihood, biomechanical, etc.) to
choose one of the three schemes over the other, but we cannot stop there and
say "This is the *right* answer."  The best we can say is "This is the right
answer, given current data".  The addition of new data could potentially
cause us to reject the currently accepted scenario in favor of one of the
other two.>>

Right. But there is only one True answer (multiple choice question), and a
cladogram that indicates a different phylogeny from the True answer is wrong,
regardless of whether we can discern it and regardless of the perfection or
interpretation of current data. If we believe, for whatever reasons, that we
have a true cladogram when in reality it is wrong, then we are living in a
fool's paradise. I would say it is worthwhile to dedicate some research toward
solving the problem of verifying the Truth of cladograms, especially since the
number of choices is quite finite, rather than wishy-washily dismissing the
issue as insoluble. The possibility of living in a fool's paradise makes me
edgy (no snide comments here, please; I've anticipated them all already).