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Darwin-L Message Log 5:52 (January 1994)

Academic Discussion on the History and Theory of the Historical Sciences

This is one message from the Archives of Darwin-L (1993–1997), a professional discussion group on the history and theory of the historical sciences.

Note: Additional publications on evolution and the historical sciences by the Darwin-L list owner are available on SSRN.


<5:52>From hantuo@utu.fi  Mon Jan 10 18:28:22 1994

To: Darwin-L@ukanaix.cc.ukans.edu
From: hantuo@utu.fi (Hanna Tuomisto)
Subject: re: DARWIN-L digest 115
Date: 	Tue, 11 Jan 1994 02:31:31 +0200

Fraser Neiman wrote that to become accepted, a hypothesis needs to fit not
only the evidence but also other theories. Indeed, this is one of the main
ways how science guarantees that the views about the world that finally get
accepted are coherent. We do not want to accept a bunch of hypothesis, even
if each of them fits some facts, if the total picture becomes fragmented
and internally inconsistent.

Since all new hypothesis are evaluated against the previously accepted
ones, it is very difficult to get such a hypothesis accepted that would
require the modification of "what we already know". Of course this is how
it should be. But scientific knowledge is not absolute, and therefore we
should not categorically refuse to check on those established theories.
They might benefit from being updated.

As to the "functional package" explanations of human evolution, there are
some crucial differences between the "hands-tools-reduced canines -brain
-bipedalism" package and the packages discussed by the aquatic theory. The
"hands-tools-etc." package is a very artificial one. All these traits are
considered as important changes towards hominization, but that is the main
reason why people started to consider them together. Because this
combination of traits is not found among other animals, we do not know if
it actually is a functional package or not. The aquatic theory lumps traits
into a package on entirely different grounds, namely because of their
co-occurrence in other animal species. And since these other animals are
(semi)aquatic, we have some reason to believe that the package indeed is
adaptational and evolved in a certain ecological situation. Consequently,
the selection pressures would have acted on each of the traits separately,
but simultaneously. Thermoregulation in wet conditions? Develop fat and get
rid of hair. Locomotion in water? Become bipedal and develop a diving
ability. Breathing in water? Avoid it, and develop concious control over
breathing and a way to close the nasal passage instead. The old
"hands-tools-" sequence has no such ecology to go with it. Therefore all
the traits depend mainly on each other, and the evolution of new traits is
explained by the existence of the old ones. The result is rather shaky,
though, and the sequence of events is far from clear.

Hanna Tuomisto
hantuo@utu.fi

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