Burden of Proof out of place

[Larry Trask]

On Thu, 12 Aug 1999 ECOLING at aol.com wrote:

> No Burden of Proof is appropriate on the content of the question
> whether all languages are ultimately related,
> simply because we cannot test that question currently.

I fully agree that the question `Are all languages related?' cannot be
answered at present.  I further believe that we will never be able to
answer this question by purely linguistic means.

However, there are people who disagree, one of the most prominent being
Merritt Ruhlen.  Ruhlen wishes to embrace the conclusion `All languages
are related.'

Now, in order to go about this, I maintain, he should start with the
negation of this statement as his null hypothesis, and then go on to
show that there is so much evidence against this null hypothesis that it
is untenable and must be rejected.  But that's not what he does.

Instead, he *starts* with the hypothesis `All languages are related',
and then proceeds to assemble what he sees as evidence in support of
this last hypothesis.  Amazingly enough [;-)]. he is able to find such
evidence.  He therefore declares that, because he has found evidence in
support of his desired conclusion, it must be true.  But this is
completely wrongheaded.

What Ruhlen *must* do, if he wants to persuade anybody, is not to try to
demonstrate that his favored conclusion is supported by evidence, but
rather that its contradictory -- the appropriate null hypothesis -- is
so strongly disconfirmed that it cannot be maintained.

To draw a crude analogy, suppose I am interested in persuading you of
the truth of the proposition `All swans are white.'  In this
undertaking, it will be wholly inadequate for me merely to show you a
whole bunch of white swans.  Instead, I must undertake the more
difficult task of disconfirming the contradictory, `Some swans are not
white.'  That is, I must adduce powerful evidence that no non-white swan
is to be found anywhere.

What Ruhlen does is effectively to produce a number of white swans.  He
has entirely failed to understand the need to disconfirm the required
null hypothesis -- the contradictory of the conclusion he wants to reach
-- and he has contented himself with merely assembling scraps of
evidence -- or what he sees as evidence -- in support of his desired
conclusion.  As a result, he has completely failed to produce any
grounds at all for rejecting the true null hypothesis: `Some languages
are not related'.

This fundamental failure to understand proper methodology is enough to
render Ruhlen's work vacuous, quite apart from the vast number of
egregious errors in the material he cites as evidence, and quite apart
from his failure to realize that lookalikes do not constitute evidence
of any kind.

Larry Trask
COGS
University of Sussex
Brighton BN1 9QH
UK

larryt at cogs.susx.ac.uk