This is a rather technical post that might interest McEvoy (or else might
not). It was provoked by Lionpainter/Chickenpainter's expansion on Ritchie's
occasional reference to his chickens (are they 'his'?) as 'dinosaurs'. Is
he being 'metaphorical'? Is he being Popperian? Finally, is he being
Griceian?
McEvoy was referring to some usages of Popperianism, and the recent
fascinating link provided by Lionpainter (aka Chickenpainter) on the dinosaur
as
the 'mother of all', led to me yet another link, which uses some Popperian
terminology. So I shall try and provide some commentary.
At
http://www.ucmp.berkeley.edu/diapsids/avians.html
"Ask your average paleontologist who is familiar with the phylogeny of
vertebrates and they will probably tell you that yes, birds (avians) are
dinosaurs. Using proper terminology, birds are avian dinosaurs."
Popper might regard this as definitional and stipulatory and hardly
advancing science. And he might be right!
The link goes on:
"[O]ther dinosaurs are non-avian dinosaurs, and (strange as it may sound)
birds are technically considered reptiles. Overly technical? Just
semantics? Perhaps."
I think this reference to 'just semantics' (NOT 'fair' semantics) may be
interpreted Popperianly, since he was adamant that meaning analysis played
SOME role in philosophy (qua conceptual analysis) but was a hoax in science
(McEvoy, a Popperian, sees it as a hoax in philosophy, too!).
"[B]ut still good science. In fact, the evidence is overwhelmingly in
favour of birds being the descendants of a maniraptoran dinosaur, probably
something similar (but not identical) to a small dromaeosaur. What is this
evidence?"
Recall Grice, "Do not say what you lack adequate evidence for". He
distinguishes that from "Do not say what you believe to be false". He later
thought that perhaps both maxims overlapped, since how adequate can FALSE
evidence be?
The link goes on:
"We'll spare you the exhaustive amount of available cladistic studies;
those alone would make a large book if compiled. Dr. Jacques Gauthier, during
his time as a graduate student of Professor Kevin Padian at Berkeley"
-- in whose campus there is The Grice Bench -- (someone informed me that
this Grice Bench should not be confused with a downtown art gallery in Los
Angeles also called "The Grice Bench", but less philosophical in nature --
and not really a 'bench bench'.
"... did his dissertation research on this subject, creating the first
well accepted, detailed phylogeny of the diapsids. Gauthier's provided strong,
compelling support for the theory that birds are theropod dinosaurs."
Popper might still be unsatisfied; for him, it's compelling FALSIFICATION
that matters.
The link goes on:
"If we look back into the history of the issue, it is apparent that many
comparative anatomists during the 16th through 19th centuries noticed that
birds were very similar to traditional reptiles. In 1860, shortly after the
publication of Charles Darwin's influential work On the Origin of Species By
Means of Natural Selection,"
-- A book Popper respected at what I might call the 'meta-philosophical'
level, i.e. as informing his approach to, say, problem-solving -- and
notably after Campbell had popularised a sort of 'evolutionary epistemology'.
"... a quarry worker in Germany spotted an unusual fossil in the limestone
of the Solnhofen Formation (late Jurassic period). This fossil turned out
to be the famous 'London specimen' of Archaeopteryx lithographica. It was a
beautiful example of a "transitional form" between two vertebrate groups
(traditional reptiles and birds); just what Darwin expected would eventually
be found."
This still fits Popper's idea of inductivism and confirmationism; not his
revered falsificationism.
"Archaeopteryx, generally accepted as being the oldest known bird, is an
important link between birds and other coelurosaurs that has helped to
illuminate the evolutionary history (phylogeny) of the group. It is now widely
held to be the ancestor of all living birds; this is a common misconception."
The author means that this is false. We are getting Popperian here.
The link goes on:
"In fact, recent expeditions in China, Mongolia, Madagascar, Argentina,
and elsewhere may uncover dinosaurs that usurp the "urvogel" status of
Archaeopteryx."
The China reference relates to Lionpainter's link about the feathered
dinosaur, which incidentally, is covered in the Wikipedia entry for "Origin of
birds".
Our link goes on:
"Many scientists, including Thomas Henry Huxley (a staunch supporter of
Darwin), saw incredible similarities between birds and the theropod dinosaurs
(especially the coelurosaurs). Others since Huxley also hinted at the
striking resemblances. However, birds were still not well accepted as dinosaur
descendants — such hypotheses as A. Walker's "crocodylomorph" ancestor and
G. Heilman's "thecodont" ancestor held sway for most of the 19th and 20th
century, or else birds were simply dismissed as originating from some unknown
reptile that didn't matter anyway. That would change. Dr. J.H. Ostrom's
1969 description of Deinonychus antirrhopus and its similarities to
Archaeopteryx was the major step: his work since the 1970s has provided the
impetus
for a paradigm shift in paleontologists' visions of the origin of birds and
the evolution of flight."
The link's use of 'paradigm shift' is Kuhnian, of course, and we are
recalled that perhaps Popper was never to happy with Kuhn's discoveries (or
points).
The link goes on:
"Gauthier's cladistic work in the mid-1980s provided the best analytical
systematic support for the theory that birds are the descendants of
dinosaurs. Several independent analyses by other scientists have repeatedly
upheld
Gauthier's results. Today the important issue seems to be specifically
WHICH dinosaurs are the closest relatives of birds."
Specification of hypothesis, in Popper's hypothetico-deductive method, one
would think.
The link goes on:
"The controversy over the dinosaurian status of birds had its heyday in
the 1970s, but the coverage of the issue today by the press might make you
think it was still a problematic matter. For those that have actually seen
the relevant specimens and considered all of the relevant data (which is a
basic procedure for any scientist), it is becoming increasingly difficult to
draw the line between "bird" and "non-avian dinosaur"".
Still not impossible, we hope! It's only when it has becoming TOTALLY
UNFALSIFIABLE to draw lines that a Popperian protests!
The link goes on:
"Some researchers today do not agree that dinosaurs gave rise to birds,
and are working to falsify this theory,"
This is an obvious reference to Popper's philosophy of science. The good
thing is that the intent to falsify is ascribed to researchers, and not
philosophers of science as Popper, which gives Popper's philosophy of science
a
'realistic' undertone, since he is reconstructing what scientists do, not
what he thinks they should do!
The link goes on:
"But so far the evidence for the theory has swamped their efforts. If they
were to conclusively establish that birds are more likely descended from
another group (Crocodylomorpha, the group containing crocodiles, has been
suggested), that would be a major upheaval in our knowledge of phylogeny."
That would refute (falsify, refudiate) the previous hypothesis and would
be scientific progress.
"One single well-preserved fossil bird unequivocably of Triassic age might
shed some doubt on the theory of the maniraptoran affinities of birds.
That would be a major find. Some bird-like fossils have been presented as
Triassic birds, but so far have not held up under peer review. Such is the
dynamic nature of science. So you may be thinking now, what are these striking
resemblances between birds and other dinosaurs?"
"The ratite birds -- such as the emu, the ostrich, and the kiwi -- are
quite similar to theropod dinosaurs. Some of the similarities may be
superficial, but others may be too obvious to dismiss,"
And shouldn't it all be a matter of DNA? DNA is hardly superficial, yet
still 'observational', a criterion for Popper.
The link goes on:
"And in any case all available data must be considered. We'll start with
the "reptilian" similarities of birds. Like all other reptiles, birds have
scales (feathers are produced by tissues similar to those that produce
scales, and birds have scales on their feet). Also, birds lay eggs like other
reptiles. The soft anatomy (musculature, brain, heart, and other organs) all
are fairly similar; birds are more derived in some aspects owing partially
to their endothermic metabolism and their ability to fly. There are
numerous skeletal resemblances between birds and other reptiles; these form
the
basis of the cladistic analyses done by Gauthier and others. Coelurosaurian
dinosaurs are thought to be the closest relatives of birds, in fact, birds
are considered to be coelurosaurs. This is based on Gauthier's and others'
cladistic analyses of the skeletal morphology of these animals. Bones are
used because bones are normally the only features preserved in the fossil
record. The first birds shared the following major skeletal characteristics w
ith many coelurosaurian dinosaurs (especially those of their own clade, the
Maniraptora, which includes Velociraptor): pubis (one of the three bones
making up the vertebrate pelvis) shifted from an anterior to a more posterior
orientation (see Saurischia), and bearing a small distal "boot"; elongated
arms and forelimbs and clawed manus (hands); large orbits (eye openings in
the skull); flexible wrist with a semi-lunate carpal (wrist bone); hollow,
thin-walled bones;3-fingered opposable grasping manus (hand), 4-toed pes
(foot); but supported by 3 main toes;reduced, posteriorly stiffened tail;
elongated metatarsals (bones of the feet between the ankle and toes); S-shaped
curved neck; erect, digitgrade (ankle held well off the ground) stance
with feet postitioned directly below the bod; similar eggshell microstructure;
teeth with a constriction between the root and the crown; functional basis
for wing power stroke present in arms and pectoral girdle (during motion,
the arms were swung down and forward, then up and backwards, describing a
"figure-eight" when viewed laterally); expanded pneumatic sinuses in the
skull; five or more vertebrae incorporated into the sacrum (hip); straplike
scapula (shoulder blade); clavicles (collarbone) fused to form a furcula
(wishbone); hingelike ankle joint, with movement mostly restricted to the
fore-aft plane; secondary bony palate (nostrils open posteriorly in throat);
possibly feathers."
Feathers being the main issue in the link provided by Lionpainter
(Chickenpainter).
"[T]his [last feature: presence of feathers] awaits more study. Small,
possibly feathered dinosaurs were recently found in China."
A reference to the link provided by Lionpainter/Chickenpainter.
"It appears that many coelurosaurs were cloaked in an external fibrous
covering that could be called "protofeathers.""
And a Popperian might object to a protofeather being a feather?
The link concludes:
"Some researchcers have raised issues that may seem to make the theropod
origin of birds difficult to support, but these difficulties are more
illusory than substantial. One proposed difficulty is the gap in the fossil
record between the first known bird (Late Jurassic) and the dromaeosaurs,
probable sister group of birds (Early Cretaceous). This overlooks the blatant
fact that other maniraptoran coelurosaurs, such as Ornitholestes, Coelurus,
and Compsognathus, are known from strata of Late Jurassic age. If other
maniraptorans were there, it logically follows that the ancestors of
dromaeosaurs were there."
Must say I love that use of 'logically follows' and it nicely combines
with the other thread McEvoy was considering: The Wikipedia's account of the
role of tautology and the definition of a valid deductive argument in the
Tractatus and how challenged all that can be!
The link goes on:
"Fragmentary remains of possible dromaeosaurs are also known from the Late
Jurassic. Other arguments, such as the putative differences between
theropod and bird finger development, or lung morphology, or ankle bone
morphology, all stumble on the lack of relevant data on extinct theropods,
misinterpretations of anatomy, simplifying assumptions about developmental
flexibility, and/or speculations about convergence, biomechanics, or selective
pressures."
This may have Popperian relevance, in that selection IS the keyword for
that sort of Darwinism he embraced.
The link goes on:
"The opponents of the theropod hypothesis refuse to propose an alternative
hypothesis that is falsifiable."
-- which is Popperianism 101.
The link goes on:
"This is probably because there are no other suitable candidates for avian
ancestors. "Thecodonts" are often promoted as such, but this is an
obfuscatory, antiquated term for a hodgepodge of poorly understood and
paraphyletic, undiagnosible reptiles. The problems cited by such opponents for
theropods are often more serious for the "thecodont" pseudo-hypothesis."
-- which is not a hypothesis. I don't think Popper uses
'pseudo-hypothesis', but I think he has have used 'pseudo-': he would say
metaphysics is
pseudo-science, e.g.? (Take cosmology: there's scientific cosmology and
metaphysical cosmology. Is metaphysical cosmology pseudo-scientific cosmology,
and
vice versa?)
The link concludes:
"Finally, such opponents also refuse to use the methods and evidence
normally accepted by comparative evolutionary biologists, such as phylogenetic
systematics and parsimony. They rely more on an "intuitive approach," which
is not a method at all but just an untestable gestalt impression laden with
assumptions about how evolution must work."
The use of 'laden' may be perhaps too weak a word to attest the author of
the link is thinking Hanson (who made his career on the idea of
theory-laden observation, if not 'gestalt').
The link goes on:
"The "controversy" remains an interest more of the press than the general
scientific community. There are more interesting issues for scientists to
explore, such as how flight performance changed in birds, what the earliest
function(s) of feathers was(were), when endothermy arose in some
archosaurs, which group of theropods was ancestral to birds, how theropod
ecology
changed with the acquisition of flight, why some bird groups survived the
Cretaceous extinction of other dinosaurs, etc. Without its feathers,
Archaeopteryx looks much like a small coelurosaur such as a dromaeosaurid or
troodontid. The facts are resoundingly in support of a maniraptoran origin for
birds; certainly a theropodan origin at the very least. So when you see a hawk
diving to snatch a dove, or an egret darting for fish, or an ostrich
dashing across the African savanna, know that you are gaining some insight
into
what the extinct dinosaurs were like. However, do note that extant (living)
birds are quite different from extinct dinosaurs in many ways, so it's not
safe to assume that all dinosaurs are the same. For that matter, extant
birds are quite different from Jurassic and Cretaceous birds. Time passes, the
environment changes... life evolves. Extant birds have been separated
evolutionarily from the other coelurosaurian dinosaurs for some 150 million
years, so they do look, act, and function quite differently, but science has
shown us that they are closely linked by their common evolutionary history."
"Science has shown us.": loved that. Perhaps a refudiation of Witters,
because here we have an example of what science SAYS and SHOWS: two verbs
which seem to be in an irreconciliable relationship with Witters, who once
attacked Popper with a poker, but that is another story...
Cheers,
Speranza
ps. Lionpainter/Chickenpainter was recollecting her grandmother twisting
the neck of a rooster. This reminded me of Grice, naturally, and since my
other post refers to the validity of deductive reasoning, it may be worth
considering, while talking avian, Grice's idea that severing the head of a
chicken (rather than twisting the chicken's neck) from the chicken's body
proves the immortality of the human soul.
His deductive reasoning is somewhat complicated, but I have managed to
provide the deductive schemata behind it. It may fit Witters's account of
valid deduction in the TLP (that is short for the longer, "Tractatus
Logico-Philosophicus," if you mustn't):
P1: If the soul is not dependent on the body, it is immortal.
P2: If the soul si dependent on the body, it is dependent on that part of
the body in which it is located.
P3: If the soul is located in the body, it is located in the head.
P4: If a chicken's soul were located in its head, a chicken's soul would be
destroyed if the head were rendered inoperative by removal from the body.
P5: A chicken runs round the yard after head-removal.
P6: A chicken could do this only if animated, and controlled by its soul.
P7: A chicken's soul is not located is, and not dependent on, the chicken's
head.
P8: A chicken's soul is not dependent on the chicken's body.
P9: A chicken's soul is immortal.
P10: If a chicken's soul is immortal, _a fortiori_ the human soul is
immortal.
CONCLUSION: Therefore, the soul is immortal.
------------------------------------------------------------------
To change your Lit-Ideas settings (subscribe/unsub, vacation on/off,
digest on/off), visit www.andreas.com/faq-lit-ideas.html
