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␈↓ ↓H␈↓∧␈↓ ¬X846 Lathrop Drive
␈↓ ↓H␈↓∧␈↓ ¬'Stanford, California 94305
␈↓ ↓H␈↓∧Telephone 415 857-0672␈↓ 	↑February 16, 1984




␈↓ ↓H␈↓Pat McCarthy
␈↓ ↓H␈↓2121 W. 9th St., Apt. 205
␈↓ ↓H␈↓Los Angeles, CA 90006

␈↓ ↓H␈↓Dear Pat,

␈↓ ↓H␈↓        Thanks for your letter and the clipping.

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

␈↓ ↓H␈↓        The␈αquestion␈αof␈αwhether␈αthere␈αare␈αnew␈αcombinations␈αof␈αthe␈αand/or␈αtype␈αwas␈αsettled␈αa␈αlong
␈↓ ↓H␈↓time␈αago,␈αprobably␈αby␈α
Boole␈αhimself␈αin␈αthe␈α
1840s.␈α It␈αwas␈αshown␈α
that␈αany␈αfunction␈αof␈αany␈α
number
␈↓ ↓H␈↓of␈αBoolean␈αvariables␈α(variables␈αthat␈αtake␈α"true"␈αand␈α
"false"␈αas␈αvalues)␈αcould␈αbe␈αwritten␈αin␈αterms␈α
of
␈↓ ↓H␈↓his␈α∞␈↓↓and␈↓,␈α
␈↓↓or␈↓␈α∞and␈α
␈↓↓not␈↓.␈α∞ Around␈α
the␈α∞turn␈α
of␈α∞the␈α
century␈α∞She≥er␈α
showed␈α∞that␈α
just␈α∞one␈α∞connective␈α
-
␈↓ ↓H␈↓now called the She≥er stroke - was enough.

␈↓ ↓H␈↓        While␈αthis␈α
settles␈αthe␈α
question␈αfor␈α
the␈αlow␈α
level␈αBoolean␈α
functions,␈αthere␈α
is␈αplenty␈α
of␈αroom
␈↓ ↓H␈↓for␈α⊂invention␈α⊂in␈α∂higher␈α⊂level␈α⊂programming␈α∂constructs.␈α⊂ For␈α⊂example,␈α∂I␈α⊂have␈α⊂been␈α⊂working␈α∂on
␈↓ ↓H␈↓ideas␈αfor␈αa␈αprogramming␈αlanguage␈αcalled␈αElephant␈α(it␈αnever␈αforgets)␈αthat␈αallows␈αreference␈αto␈αpast
␈↓ ↓H␈↓events␈αwithout␈αrequiring,␈αas␈αother␈αlanguages␈αdo,␈αexplicit␈αprovision␈αfor␈αstoring␈αfacts␈αabout␈αthem␈αin
␈↓ ↓H␈↓some␈α∞data␈α∂structure.␈α∞ I␈α∂hope␈α∞this␈α∞will␈α∂add␈α∞to␈α∂programming␈α∞languages␈α∞more␈α∂of␈α∞the␈α∂∨exibility␈α∞of
␈↓ ↓H␈↓natural languages.

␈↓ ↓H␈↓        Katherine␈αis␈αindeed␈αover␈αa␈αyear,␈αwalks,␈αand␈αbabbles␈αa␈αlot.␈α With␈αgood␈αwill␈αa␈αfew␈αwords␈αcan
␈↓ ↓H␈↓be recognized.  So far no other.


␈↓ ↓H␈↓Best regards,



␈↓ ↓H␈↓John McCarthy