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∂HOM Pat McCarthy↓2121 W. 9th St., Apt. 205↓Los Angeles, CA 90006∞

Dear Pat,

	Thanks for your letter and the clipping.

	Boolean algebra is more in the back of the construction of
computers than computer languages.  The user of a language thinks
more in terms of numbers or Lisp expressions or strings of characters
than in terms of bits, although these are available also.

	The question of whether there are new combinations of the
and/or type was settled a long time ago, probably by Boole himself
in the 1840s.  It was shown that any function of any number of
Boolean variables (variables that take "true" and "false" as values)
could be written in terms of his %2and%1, %2or%1 and %2not%1.
Around the turn of the century Sheffer showed that just one
connective - now called the Sheffer stroke - was enough.

	While this settles the question for the low level Boolean
functions, there is plenty of room for invention in higher level
programming constructs.  For example, I have been working on
ideas for a programming language called Elephant (it never forgets)
that allows reference to past events without requiring, as other
languages do, explicit provision for storing facts about them in
some data structure.  I hope this will add to programming languages
more of the flexibility of natural languages.

	Katherine is indeed over a year, walks, and babbles a lot.
With good will a few words can be recognized.  So far no other.

.regp