Word-count: 1,904
Contents:
i)
Introduction
ii)
John von Neumann
iii)
The Creation of Artificial Life
The
American computer scientist Christopher
Gale Langton was born 1948. He was a founder of the field of
artificial life. He coined the term “artificial life” in the late
1980s.
Langton
joined the Santa
Fe Institute
in its early days. He left the institute in the late 1990s. Langton
then gave up his work on artificial life and stopped publishing his
research.
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When
it came to Artificial Life (AL), Christopher G. Langton didn't hold
back. In the following
passage
he puts the exciting case for AL:
“It's
going to be hard for people to accept the idea that machines can be
alive as people, and that there's nothing special about our life
that's not achievable by any other kind of stuff out there, if that
stuff is put together in the right way. It's going to be as hard for
people to accept that as it was for Galileo's contemporaries to
accept the fact that Earth was not at the center of the universe.”
The
important
and relevant part of the passage above is:
“[T]here's
nothing special about our life that's not achievable by any other
kind of stuff out there...”
Although
the above isn't a definition of functionalism, it nonetheless has
obvious and important functionalist implications.
So
when it comes to both Artificial Life and Artificial Intelligence,
the computer scientist Christopher
Langton
seems to have explicitly stated that biology doesn't matter. Yes; it of course matters to biological life and biological
intelligence; though not to life and intelligence generically
interpreted.
The
biologist and cognitive scientist Francisco
Varela put
the opposite position (as it were) to Langton's when he told us that
he “disagree[s] with [Langton's] reading of artificial life as
being functionalist”. Varela
continues:
“By
this I refer to his idea that the pattern is the thing. In contrast,
there's the kind of biology in which there's an irreducible side to
the situatedness
of the organism and its history...”
What's
more:
“Functionalism
was a great tradition in artificial intelligence; it's what early AI
was all about.”
So
we have specific biologies. Those specific biologies are situated in
specific environments. And then we must also consider the specific
histories of those specific biological organisms. So, if “early AI”
was “all about” functions and nothing else, then that was surely to lave out a lot. (From a philosophical angle, we must also include
externalist
arguments, as well as
embodiment
and embeddedness –
i.e., not only Varela's “situatedness”.)
The
physicist J.
Doyne Farmer also attempted to sum up the problematic stance which
Langton held. He
writes:
“The
demonstration of a purely logical system, existing only in an
abstract mathematical world, is the goal that [Christopher Langton]
and others are working towards.”
Yet
we mustn't characterise Langton's position as mere chauvinism against
biology and even against biological
evolution.
After all, despite what Verela says about situatedness, Langton was
fully aware
that
“[a]nything
that existed in nature had to behave in the context of a zillion
other things out there behaving and interacting with”.
Langton
also appeared to criticise (early?) AI for “effectively ignor[ing]
the architecture of the brain”. That's not a good thing to do
because Langton went on to say that he “think[s] the difference in architecture is crucial””. Nonetheless, the sophistication of
this view is that just as functions and algorithms can be
instantiated/realised
in many
materials, so too can different architectures.
The
aspect of the brain's architecture that specifically interested
Langton is that it is “dynamical” and also involves “parallel distributed systems” (which are “nonlinear”). Indeed he appears
to have complimented what he calls “nature” for “tak[ing] advantage of” such things. And, by “nature”, Langton surely must have meant “biology”. (Though there are dynamical and non-linear
natural
systems which aren't biological.)
So
the early AI workers ignored the brain's architecture; whereas
Langton appeared to arguing that artificial architectures (alongside
functions and algorithms) must also be created. This, then, may be a
mid-way position between the purely “abstract
mathematical world”
of
early AI and the blind simulation of biological brains and organisms.
Having
said all the above, Langton shifts in his middle-ground again when he
says
that Artificial Life
“isn't
the same thing as computational biology, which primarily restricts
itself to computational problems arising in the attempt to analyse
biological data, such as algorithms for matching protein sequences to
gene sequences”.
Langton
continues by saying
that
“[a]rtificial
life reaches far beyond computational biology. For example, AL
investigates evolution by studying evolving populations of computer
programs – entities that aren't even attempting to be anything like
'natural' organisms".
So
Langton believes that AL theorists shouldn't “restrict[]”
themselves to “biological data”, despite his earlier comments
about noting the architecture of the biological brain (specifically, its parallel distributed processes, etc.). Yet again, Langton
either appears to be standing in a mid-way position. Or, less likely, Langton appears to contradicting himself on the precise
relation between Artificial Life and biology.
John
von Neumann
Langton
cited the case of John
von Neumann;
who, some 50
years
before his work, also attempted to create artificial life. Neumann's
fundamental idea (at least according to Langton)
is that
“we could learn a lot even if we didn't try to model some specific
existing thing”.
Now
it can be said that when theorists and technologists create life (or
attempt
to create life), then they're only creating a replication/simulation
of biological life. Von Neumann wanted to go further than this... and
so too did Langton.
To
sum up the opposition in clear and simple words, J. Doyne
Farmer says
that
“Von
Neumann's automaton has some of the properties of a living system,
but it is still not alive”.
So
if von Neumann wasn't concerned with the specific biologies of
specific creatures, then what was he concerned with? According
to Langton again:
“Von
Neumann went after the logical basis, rather than the material basis,
of a biological process.”
Even
though it was said (a moment ago) that Neumann and Langton weren't
interested in replication, they still, nonetheless, studied “biological processes”. And functionalists are keen to say
that the “material basis” simply doesn't matter. Yet if
biological processes are still
studied, then perhaps the philosopher Patricia
Churchland's
warnings to functionalists may not always be completely apt (i.e., about brain and mind). After
all, she
writes:
“[T]he
less known about the actual pumps and pulleys of the embodiment of
mental life [by functionalists], the better, for the less there is to
clutter up one's functionally oriented research.”
Indeed
that position can be seen as the very essence of most (or all)
functionalist positions. It's most technically and graphically shown
in the “multiple
realizability”
argument in which it is said that function x
can have any number of material bases and still function as
function x.
(The multiple realizability
argument
is
found most
often in the philosophy of mind.)
Von
Neumann provided a specific example of his search for the logical
bases of biological processes. Not surprisingly, since he was
concerned with artificial life, he
“attempt[ed]
to abstract the logic of self-reproduction without trying to capture
the mechanics of self-reproduction (which were not known in the late
1940s, when he started his investigations)”.
Prima
facie,
it's difficult to have any intuitive idea of how the word “logic”
(or “logical”) is being used here. Isn't the logic of
self-reproduction... well, self-reproduction?
After
all, without the “mechanics”, what else have we got?
It
seemed, then, that the logic of self-reproduction (as well as
self-replication, etc.) could be captured by an algorithm. In this
case, “one could have a machine, in the sense of an algorithm, that
would reproduce itself”. (Is the machine something that carries
out the
algorithm or is it actually the algorithm itself?) In more detail,
the logic of the biological process of self-reproduction is captured
in terms of genes and what the genes do. Thus genetic information has
to do
the following:
“(1)
it had to be interpreted as instructions for constructing itself or
its offspring, and
(2)
it had to be copied passively, without being interpreted.”
Now this is von Neumann's logic of self-reproduction – and no (technical)
biological knowledge was required to decipher those two very simple
points. And, by “no biological knowledge”, I mean no knowledge of
how information is stored in DNA. (That came later - in 1953.)
Langton concluded something very fundamental from this. He
wrote:
“It
was a far-reaching and very prescient thing to realise that one could
learn something about 'real biology' by studying something that was
not real biology – by trying to get at the underlying 'bio-logic' of
life.”
As
mentioned earlier, it may be the case that Langton over-stated his
case here. After all, even he said that “biological processes”
are studied – and indeed that's obviously the case. So we may have the
“logical basis” of biological processes; though, evidently,
biological processes aren't completely ignored. To put all that in a
question:
Did
von Neumann ever discover that this logic was instantiated/realised
in any non-biological processes?
Earlier
Francisco Verela was quoted citing the importance of “situatedness”
and “history”. These two factors are obliquely mentioned by J.
Doyne Farmer in the specific case or organisms and reproduction.
He
says:
“Real
organisms do more than just reproduce themselves; they also repair
themselves. Real organisms survive in the noisy environment of the
real world. Real organisms were not set in place, fully formed,
hand-engineered down to the smallest detail, by a conscious God; they
arose spontaneously through a process of self-organisation.”
At
first sight, it seems odd that when von Neumann attempted to create
artificial life and artificial evolution (or at least simulate artificial life and artificial evolution) that he seemed to have
ignored “real organisms” and their surviving “in the noisy
environment of the real world”. That is, Neumann's cellular
automata
were indeed “hand-engineered down to the smallest detail” and
then “set in place”. In other words, von Neumann was the god of
his own cellular automata. So no wonder Farmer sees such things in the
exclusive terms of an "abstract mathematical world”.
The
Creation of Artificial Life
On
the one hand, there's the study of the "logic" of biological processes.
On the other hand, there's the actual creation
of artificial life.
The
first step is to realise that logic in non-biological material.
Will that automatically bring forth artificial life? Langton believed
that it does
(not will) – at least in some cases. That is, the simulation of
life is actually the realisation (or instantiation)
of life. Yet, according to Langton himself, “[m]any biologists wouldn't
agree” with all this. They argue that “we're only simulating
evolution”. However, Langton had an extremely radical position on this
simulation-realisation binary opposition. He
wrote:
“[W]hat's
the difference between the process of evolution in a computer and the
process of evolution outside the computer?”
Then
Langton explained why there's no fundamental or relevant difference.
He
continued:
“The
entities that being evolved [inside the computer] are made of different stuff, but the process is identical.”
So,
again, it's the process (or the logic
of the
process) that's important, not the nature of the “stuff” that
realises that (abstracted) process. Thus process (or function) is
everything. Conversely, the material (or stuff) is irrelevant.
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