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␈↓ ↓H␈↓␈↓βS␈↓∧ Artificial Intelligence Laboratory, STANFORD UNIVERSITY, Stanford, California 94305

␈↓ ↓H␈↓∧Telephone 415 497-4430␈↓ 
&June 2, 1980 




␈↓ ↓H␈↓Dr. Richard Goody
␈↓ ↓H␈↓American Academy of Arts and Sciences
␈↓ ↓H␈↓165 Allandale Street
␈↓ ↓H␈↓Jamaica Plain Station
␈↓ ↓H␈↓Boston MA 02130

␈↓ ↓H␈↓Dear Dr. Goody:

␈↓ ↓H␈↓        The␈α∂following␈α∂remarks␈α∂are␈α∂suggested␈α∂by␈α∂your␈α∂joint␈α∂memorandum␈α∂with␈α∂Michael␈α∞McElroy
␈↓ ↓H␈↓and␈α
Philip␈αMorrison.␈α
 I␈α
would␈αlike␈α
to␈α
be␈αinformed␈α
of␈α
future␈αdevelopments␈α
towards␈α
an␈αAcademy
␈↓ ↓H␈↓study of the issues and might like to take part.

␈↓ ↓H␈↓        Looked␈α∪at␈α∩from␈α∪the␈α∪point␈α∩of␈α∪view␈α∪of␈α∩the␈α∪future␈α∪of␈α∩humanity,␈α∪space␈α∪exploration␈α∩and
␈↓ ↓H␈↓colonization has two important aspects:

␈↓ ↓H␈↓        1.␈αThe␈αdispersion␈αof␈αhumanity␈αwill␈αhelp␈αprevent␈αits␈αextermination␈αby␈αcatastrophe␈α-␈αwhether
␈↓ ↓H␈↓this catastrophe be a nuclear war, some kind of environmental disaster, or a natural disaster.

␈↓ ↓H␈↓        2.␈α∞It␈α∞will␈α
also␈α∞help␈α∞prevent␈α
the␈α∞domination␈α∞of␈α
humanity␈α∞by␈α∞any␈α
single␈α∞ideology␈α∞-␈α
whether
␈↓ ↓H␈↓this ideology be communism, capitalism or environmentalism.

␈↓ ↓H␈↓        From the point of view of individuals or groups, there are other considerations:

␈↓ ↓H␈↓        1.␈α
Some,␈αwho␈α
hope␈αto␈α
reform␈αhumanity,␈α
look␈αwith␈α
horror␈αon␈α
people␈αwith␈α
bad␈αideas␈α
escaping
␈↓ ↓H␈↓control.␈α
 The␈α
Soviet␈α
position␈α∞on␈α
space␈α
treaties␈α
seems␈α
to␈α∞express␈α
such␈α
an␈α
attitude␈α
and␈α∞many␈α
who
␈↓ ↓H␈↓propose␈αto␈αcon≡ne␈αmankind␈αto␈αthe␈αearth␈α
until␈αwe␈αcan␈αbe␈αsure␈αwe␈αwon't␈αcontaminate␈α
the␈αuniverse
␈↓ ↓H␈↓have␈α
a␈α
similar␈α
point␈α
of␈αview␈α
-␈α
no␈α
doubt␈α
with␈αsomewhat␈α
di≥erent␈α
ideas␈α
about␈α
what␈α
shouldn't␈αbe
␈↓ ↓H␈↓permitted␈α∩to␈α∩get␈α∩a␈α∩foothold␈α∩in␈α⊃space.␈α∩ I␈α∩can't␈α∩be␈α∩sure␈α∩of␈α⊃your␈α∩own␈α∩position;␈α∩it␈α∩seems␈α∩to␈α⊃be
␈↓ ↓H␈↓predicated␈αon␈αcentralized␈α
control␈αof␈αmankind's␈α
activities␈αin␈αspace,␈α
but␈αthis␈αmay␈α
only␈αbe␈αa␈α
re∨ection
␈↓ ↓H␈↓of␈α
the␈αfact␈α
that␈α
the␈αmost␈α
substantial␈αactivities␈α
of␈α
the␈αvery␈α
near␈α
future␈αrequire␈α
so␈αmuch␈α
government
␈↓ ↓H␈↓support.

␈↓ ↓H␈↓        My␈α∃own␈α⊗position␈α∃is␈α∃to␈α⊗encourage␈α∃diversity␈α⊗to␈α∃the␈α∃extent␈α⊗of␈α∃permitting␈α⊗secession␈α∃of
␈↓ ↓H␈↓government␈α∀sponsored␈α∀colonies␈α∀and␈α∀permitting␈α∀the␈α∀formation␈α∀of␈α∀new␈α∀colonies␈α∀that␈α∃owe␈α∀no
␈↓ ↓H␈↓allegiance to any government on the earth or to the U.N. or any successor to it.

␈↓ ↓H␈↓        2.␈αThose␈αwho␈αfear␈αdisaster␈αon␈αearth␈α-␈αnatural,␈αenvironmental,␈αwar,␈αor␈αpolitical␈α-␈αwill␈αwant␈αa
␈↓ ↓H␈↓means␈αof␈αescape.␈α True␈αescape,␈αgiven␈αthe␈αpower␈αof␈αweapons␈αbased␈αon␈αpresent␈αscience,␈αmay␈αrequire
␈↓ ↓H␈↓multi-generation␈αexpeditions␈αleaving␈αthe␈αsolar␈αsystem.␈α It␈αseems␈αthat␈αpresent␈αscience␈αwould␈α
support
␈↓ ↓H␈↓a␈α∂technology␈α∞for␈α∂such␈α∞expeditions␈α∂leaving␈α∞as␈α∂early␈α∞as␈α∂the␈α∞end␈α∂of␈α∞the␈α∂present␈α∂century,␈α∞although
␈↓ ↓H␈↓postponed expeditions would arrive at their destinations sooner.
␈↓ ↓H␈↓αDr. Richard Goody␈↓ ¬yJune 2, 1980␈↓ 
nPage 2␈↓ 


␈↓ ↓H␈↓        I have written a manuscript about this deriving a formula

␈↓ ↓H␈↓        ␈↓↓t = 2 s␈↓2/3␈↓↓ p␈↓-1/3␈↓↓␈↓

␈↓ ↓H␈↓where␈α␈↓↓s␈↓␈αis␈αthe␈αdistance␈αto␈αa␈αgoal,␈α⊗t␈αis␈αthe␈αtime␈αrequired␈αto␈αreach␈αit,␈αand␈α⊗p␈αis␈αthe␈α≡gure␈αof␈αmerit
␈↓ ↓H␈↓of␈αthe␈αpower␈αsystem␈αin␈αwatts␈αper␈αkilogram.␈α The␈αsystem␈αuses␈αa␈αpower␈αsource␈α(e.g.␈αa␈α≡ssion␈αreactor)
␈↓ ↓H␈↓to␈αexpel␈α
a␈αworking␈α∨uid␈α
(e.g.␈αin␈α
the␈αform␈αof␈α
ions␈αor␈α
other␈αcharged␈αparticles)␈α
at␈αan␈αexhaust␈α
velocity
␈↓ ↓H␈↓that␈αvaries␈αoptimally␈α
during␈αthe␈αjourney.␈α Nearby␈α
stars␈αare␈αreached␈αin␈α
the␈αlow␈αthousands␈αof␈α
years,
␈↓ ↓H␈↓and␈α→because␈α_of␈α→the␈α_factor␈α→␈↓↓p␈↓-1/3␈↓↓␈↓,␈α_improving␈α→the␈α_technology␈α→doesn't␈α_change␈α→the␈α_answers
␈↓ ↓H␈↓qualitatively.

␈↓ ↓H␈↓        Of␈α
course,␈α
interstellar␈αescape␈α
in␈α
the␈α
next␈αfew␈α
hundred␈α
years␈α
unless␈αthere␈α
is␈α
an␈α
advance␈αin
␈↓ ↓H␈↓science,␈αwill␈αbe␈αof␈αinterest␈αonly␈αif␈αa␈αgroup␈αfeels␈αrather␈αdesperate,␈αbut␈αthere␈αmay␈αbe␈αsuch␈αgroups␈αif
␈↓ ↓H␈↓mankind evolves towards ideological monopoly.

␈↓ ↓H␈↓        Anyhow,␈α
most␈α
of␈α
our␈α
attention␈α
should␈αbe␈α
devoted␈α
to␈α
the␈α
exploration␈α
and␈α
colonization␈αof␈α
our
␈↓ ↓H␈↓own solar system.

␈↓ ↓H␈↓        I␈α↔am␈α↔somewhat␈α_surprised␈α↔that␈α↔your␈α_memorandum␈α↔didn't␈α↔mention␈α_the␈α↔controversies
␈↓ ↓H␈↓surrounding the proposed moon treaty as prototypical of issues that will arise.

␈↓ ↓H␈↓        Your␈α⊃remarks␈α⊃about␈α⊂self-reproducing␈α⊃arti≡cial␈α⊃systems␈α⊃suggest␈α⊂the␈α⊃comment␈α⊃that␈α⊃such␈α⊂a
␈↓ ↓H␈↓system␈α∪can␈α∪be␈α∪regarded␈α∩as␈α∪a␈α∪limiting␈α∪case␈α∪of␈α∩increased␈α∪∨exible␈α∪automation.␈α∪ A␈α∪system␈α∩that
␈↓ ↓H␈↓manufactures␈α
new␈α
components␈αfor␈α
itself␈α
according␈α
to␈αcomputer␈α
programs␈α
written␈α
and␈αcontrolled␈α
by
␈↓ ↓H␈↓humans␈α∂only␈α∂needs␈α∂a␈α∂new␈α∂top-level␈α∂program␈α∂to␈α∂become␈α∂a␈α∂self-reproducing␈α⊂machine.␈α∂ However,
␈↓ ↓H␈↓there␈α
seems␈α
to␈α
be␈α
little␈α
advantage␈α
to␈α∞us␈α
in␈α
making␈α
the␈α
system␈α
entirely␈α
independent,␈α
and␈α∞there␈α
is
␈↓ ↓H␈↓especially little advantage in having it split up into independent self-controlled units.

␈↓ ↓H␈↓        Let␈α
me␈α
re-iterate␈α
my␈α
interest␈α
in␈α
taking␈α∞part␈α
in␈α
Academy␈α
discussions.␈α
 You␈α
will␈α
≡nd␈α∞me␈α
an
␈↓ ↓H␈↓advocate␈αof␈αthe␈αidea␈αthat␈αhumanism␈αrequires␈αtolerating␈αand␈αencouraging␈αdiversity␈αin␈αsolar␈αsystem
␈↓ ↓H␈↓exploration and exploitation.


␈↓ ↓H␈↓Sincerely,



␈↓ ↓H␈↓John McCarthy
␈↓ ↓H␈↓Director
␈↓ ↓H␈↓Professor of Computer Science