No subject

Vaughan Pratt pratt at cs.Stanford.EDU
Thu Jan 15 20:52:08 EST 1998

Date: Thu, 15 Jan 1998 16:26:44 -0700 (MST)
From: Reuben Hersh <rhersh at>
>How to answer Frege?  These different twos or simplices are not unrelated or 
>disconnected.  They match each other!
>They are connected by a common schooling and communication,
>which constrantly wipe out differences and keep your imaginary simplex
>and my imaginary simplex congruent to each other.

Doesn't this conflict with what the SETI crowd believes?  There seems
to be a widely held expectation that, however little culture any
extraterrestrial civilizations out there have in common with us, at
least they will share our understanding of the basics of number theory.

One proposal based on this expectation is to transmit packets of bits
of length pq where p and q are prime, hoping that the recipients will
factor pq and lay out the bits in a pxq array to obtain a two-dimensional
monochrome image.  (This goes along with the expectation that the
contacted civilization also understands the concept of a 2D image.)

Would you say that these numerically based proposals for communicating
with civilizations that have hitherto had no contact with us are
misguided?  (Note that I am not asking whether the whole Search for
ExtraTerrestrial Intelligence is misguided, just this numerical facet
of it.)

Name: Vaughan Pratt
Position: Professor of Computer Science
Institution: Stanford University
Research interests: Foundations of computation and mathematics
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