Chapter 8: Self-reproducing programs
Chapter 8
Self-reproducing
computer programs
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Chapter 8: Self-reproducing programs
Enrico Fermi, 1901-1954
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A morning discussion about
extra-terrestrial life…
lead to a lunch-time question
from Fermi:
Where are they?
Chapter 8: Self-reproducing programs
The Fermi Paradox
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300,000 l-y300
Chapter 8: Self-reproducing programs
The Fermi Paradox…
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• Our sun is a typical star
• Billions of stars are billions of years
older than the sun
• Plenty of time for advanced cultures
to explore the Milky Way
Where are they?
Chapter 8: Self-reproducing programs
The Fermi Paradox…
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Where are they?
We don’t know
Chapter 8: Self-reproducing programs
The Fermi Paradox…
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Chapter 8: Self-reproducing programs
John von Neumann, 1903-1957
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• member of the Hungarian Phenomenon
• the Martians of the Manhattan Project
• von Neumann
• Szilard
• von Karman
• Wigner
• Teller
• strongly anti-communist
Chapter 8: Self-reproducing programs
John von Neumann, 1903-1957…
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• interested in self-replicating
machines
• von Neumann Universal
Constructor
Chapter 8: Self-reproducing programs
John von Neumann, 1903-1957…
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self-replicating probes
Chapter 8: Self-reproducing programs
von Neumann probes
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current state of the art: 3D printing
Chapter 8: Self-reproducing programs
von Neumann probes…
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Jewish folklore
Most famously,
16th century Prague
Chapter 8: Self-reproducing programs
Artificial life
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Wolfgang von Kempelen
Chapter 8: Self-reproducing programs
Artificial life…
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Chapter 8: Self-reproducing programs
Artificial life…
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Very contentious topic
Two general forms
•Strong A-Life
•Weak A-Life
Chapter 8: Self-reproducing programs
Artificial life (A-Life)
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Strong:
"life is a process which can be
abstracted away from any particular
medium“ (JvN)
Computer programs are not simulating
life but are synthesizing it
In some sense it defines away the
distinction
Chapter 8: Self-reproducing programs
A-Life…
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Weak:
Impossible to create life outside of
a chemical medium.
Simulations useful to investigate
underlying processes of biological life
Chapter 8: Self-reproducing programs
A-Life…
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Some objections (Mitchell)
• Autonomy
• Metabolism
• Self-replication
• Survival drive
• Evolution
Chapter 8: Self-reproducing programs
A-Life…
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Scale differences
• biological processes have evolved
into systems of daunting
complexity
• interactions at the scale of
• 𝑁𝐴2 = 1047
Chapter 8: Self-reproducing programs
A-Life…
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Scale differences…
• computational processes are
currently scale limited to about
• 𝑁𝑃2 = 109 interactions
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𝑁𝐴
2
𝑁𝑃
Chapter 8: Self-reproducing programs
A-Life…
≈ 1038
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an adult hermaphrodite C. elegans worm
www.openworm.org
Chapter 8: Self-reproducing programs
A-Life…
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Book draws attention to the fact that
program self-replication does not
include the interpreter, whereas DNA
does.
A distinction without a difference?
Chapter 8: Self-reproducing programs
Self-replication, DNA,
interpreters, etc
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The
Singularity
Chapter 8: Self-reproducing programs
Computer replication,
evolution and
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Chapter 8: Self-reproducing programs
Aside: the Institute for
Advanced Study
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Chapter 8: Self-reproducing programs
Aside: the IAS computer…
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