Date: Fri, 31 May 1996 20:20:14 -0400
To: Athena Discuss 
Subject: Re: Age of the Sphinx

In response to Tom Anderson's post, I'll treat the matter
syllogistically, so as to lay bare the logical issues
involved.  The empirical ones are of a different sort, in
which my competence is limited to common-sense.

Schoch-West's argument involves the use of modus ponendo
ponens, and is quite simple:

   If WP of type S, then R      (1)
   If R then AD                 (2)

where mnemonic abbreviations are adopted, thus:

   WP = weathering pattern
   S  = exhibited by sphinx
   R  = rainfall induced
   AD = sphinx creation date is ante-deluvian

I assert merely that to attack this syllogism, it is necessary
to attack either or both of the major premises.  The minor
premise needed to trigger the syllogism, namely the antecedent
"WP of type S" is not in dispute, it being there for all to see.

I therefore have no *logical* quarrel with an attempted
refutation which attempts to substitute an alternative to
the first major premise, thereby denying the first consequent R,
and therefore denying the minor premise necessary to trigger
the second major premise.

What I have a quarrel with is an attempted refutation which
goes as follows:

   If AD then AE                (3)
   not-AE, therefore not-AD     (4)

where:
   
   AE = (archaeological) evidence showing remains of a society
        of "requisite" complexity

This is modus tollendo tollens, with which I have no logical
quarrel per se.  Where I have difficulty, as I have said
repeatedly, seemingly to little avail, is that the minor
premise "not-AE" cannot be asserted because to assert it is
to assert the non-existence of AE, as opposed to it being
merely not yet found.  That is what I mean by absence of
evidence not being evidence of absence.  Now, if you have
good reason to believe that if AE exists, it would have been
found, that is another matter (Holmes' dogs that did not bark).
That has also been asserted, but I do not give that claim any 
credence, because new archaeological finds are discovered 
all the time, and because no archaeologist can ever *know*, 
ahead of time, that he is looking in the right place.  

That really ends the logical issue, and nothing in Tom 
Anderson's post refutes these logical contentions.

As to the empirical issue, it is squarely whether (1) above
is true as a matter of reality.  I do not know, and neither
does Mr. Anderson.  However, Schoch-West's main argument is
that rainfall-induced weathering shows a vertical pattern,
while wind-induced weathering shows a horizontal pattern.
That is borne out in the pictures.  Flood-induced weathering
would be another matter, and my common-sense tells me that
the patterns left by flooding would be different yet again
from rainfall-induced weathering, even granting that the
Nile may have in times past caused flooding all the way up
to the Giza plateau.  Similarly, chemical weathering due to
minerals within the rock itself reacting with or dissolving
in ground-water, I would expect to look very different from
the vertical patterns pointed out by Schoch.  Etc., etc.
In any case, the issue would be whether some alternative to
(1) is more likely, rather than being capable of its
strict refutation.  But the modus tollendo tollens mounted
in (3) and (4) simply carries no logical force as attempted
refutation, though I would concede, in the absence of AE,
(as opposed to strict non-existence) one may be entitled to
treat Schoch-West with some suspicion.


Thomas Anderson wrote:
> 

>  Why don't you just come out and say what you constantly imply with
> this catechism about the absence of evidence: "absence of evidence
> establishes a credible case for the existence of absent evidence."
>     The point I made was that the fruits of more than a century of
> archaeological excavations hardly counts as absence of data.  There is
> a process of development and change observable in the record--beginning
> before the putative date suggested by Schoch/West--and continuing
> beyond it.

Please don't put words in my mouth.  See above for what I
hope is a clear exposition.


> I don't want to get sidetracked here, but really...?  Does this mean
> that humanity in general and Africans in particular didn't evolve in
> Africa?  Or was Atlantis colonized from Africa?  Seriously though, I do
> not find speculative theories, like Atlanteans building the sphinx (or
> pyramids in the Americas), to be interesting or captivating.  Mostly I
> find them to be a waste of time, the type of thing that readers of the
> _National Enquirer_ might find intriguing.

I keep a slightly more open mind...


> "Presence of evidence," that is the whole point isn't it?  There is
> much more evidence to support our understanding of the development of
> early civilizations than for the theory of human origins.  But you are
> arguing that the better supported understanding fails because "absence
> of evidence is not evidence of absence" while the other is more valid.
> You accept the idea that archaeologists/anthropologists can establish
> processes of development and change through their work when it suits
> you, but otherwise you argue that archaeology cannot be trusted because
> it can't prove a negative.  So who is making a specious argument?

There is a clear logical fallacy here.  But I'll leave it
to you to sort out.  There are lots of hints earlier.

> ST wrote:
> >there is presence of evidence for the Schoch/West hypothesis,
> 
> TA answers:
> No there isn't, not really.  They make a claim, and offer a plausible
> argument to support that claim.  To give their hypothesis greater
> weight than the accumulated archaeological evidence is absurd.

No, I'm merely being strict about "not-found" masquerading as
"do-not-exist".


> You make an assumption that Schoch's geological theory has more merit
> than the work of hundreds of archaeologists and more than a century of
> labor.  Why?  At a certain point lack of evidence must be regarded as
> indicating that none exists to be found.

That point is reached only when you can honestly say you've
looked *everywhere*.  I asked whether the archaeologists have
dug as deeply as Mt. Rushmore is high, for a very good reason
which I'm sure has not escaped you.  You ignored it.  I also
asked the implied question whether future archaeologists 
digging around an outcropping bearing the likenesses of 
four U.S presidents carved into the rock, would find the 
essential evidence of 20th century U.S civilization, and wouldn't
they instead have to look fairly far away, in New York city
or Washington, DC.  The same might be the case for the 
sphinx.


> There you go again, assuming that geology is superior to archaeology.

See above.  I make no such *assumption*.

> What supporters of any new theory must do is prove, within reason, the
> likelihood of their theory.  

Quite.  See (1) and (2) above.

> First, Schoch/West must convince most
> other geologists that no alternative geological explanation suffices to
> account for their core observations about the sphinx's erosion
> patterns, rainfall, etc. They haven't achieved this consensus within
> their own discipline yet.  

I had a different impression.

> Assuming such consensus within the
> geological community--but still without archaeological evidence to
> buttress their claim about the age of the sphinx--the most reasonable
> explanation (the Occam's razor solution) would be that a previously
> eroded outcropping of rock was fashioned into the sphinx during the old
> kingdom (an idea raised earlier by some on this list).  

Occam had a razor, not a guillotine, which is what you would
seem to want to apply to Schoch-West.

> It is only if
> supporters of Schoch/West can show some credible archaeological data,
> or at least demonstrate logically why currently prevailing ideas are
> suspect on _historical_ grounds, that archaeologists should begin to
> re-examine some of their basic assumptions about when complex societies
> emerged in the Nile valley.   Until that time the onus is on
> Schoch/West and their supporters.  This is the way that both historians
> and experimental scientists proceed.

I disagree.  Speaking as an engineer and logic-ist, I sit humbly
before fact, and I regard logical rigor as a fairly cheap
way of averting costly mistakes, even disasters.  Historians
evidently do not have the benefit of swift kick-in-the-pants
reality checking, and can perhaps for that reason afford to 
hold on longer to cherished falsehoods.


> Tom

Regards,

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