Darwin's Dangerous Idea - Evolution and the Meaning of Life

420 THE EVOLUTION OF MEANINGS
Pole than to the South Pole, and Bo had not forgotten that his first
French teacher was named Dupont, these would not be truths that
either would be apt to put in his data base. But if you doubt that the
mere fact that they were both intent on creating an internationally
useful encyclopedia would ensure such a close correspondence be
tween their respective data bases, just add, as an inelegant detail, the
convenient fact that they compared notes as to topics to be covered
during their years of hacking.
(2)Why not just have Al and Bob (a fellow American), or, for that matter,
why not simply have a duplicate of Al's system in box B? Because it
must be the essence (oops!) of my story that no simple, feasibly
discoverable syntactic matching up could explain the regu-larity. That
is why Bo's system is in Swedish Lisp—to conceal from prying eyes
the underlying semantic commonalities between the data structures
consulted during A's sentence-generation task and B's sentencetranslation-and-truth-testing
task. The idea was to create two systems
that exhibited the fascinating regularity of external be-havior
described but that were internally as different as possible, so that only
the fact that their respective innards were systematic representations
of a common world could explain the regularity.
(3) We might pause to ask whether or not two such systems could ever be
so inscrutable as to be invulnerable to reverse engineering. Cryptography
has moved into such rarefied and arcane regions that one
should think thrice at least before declaring either way. I have no idea
whether anybody can make a sound argument to the effect that there
are unbreakable encryption schemes or that there aren't. But, encryption
aside, hackers will appreciate that all the convenient comments
and other signposts one places in the "source code" when
composing a program vanish when the source code is "compiled,"
leaving behind an almost impossible-to-decipher tangle of machine
instructions. "Decompiling" is sometimes possible in practice (is it
always possible in principle?), though of course it won't restore the
comments but just render salient the structures in the higher-level
language. My assumption that the scientists' efforts at decompiling the
program and deciphering the data bases came to naught could be
strengthened by postulating encryption, if need be.
In the story as told, we can agree that it is bizarre that the scientists never
thought of checking to see if there was an ASCII translation of the bit
streams running through the wire. How could they be so dense? Fair enough:
send the whole gadget ( boxes A and B, and the connecting wire ) to "Mars,"
and let the alien scientists there try to figure out the regularity. The fact that
all a's cause reds, all ß's cause greens, and random bit strings cause ambers
Blocking the Exits 421
will be just as visible to them as to us, but they will be clueless about ASCII.
To them, this gift from outer space will exhibit an utterly mysterious regularity,
totally beyond all analytic probes, unless they hit upon the idea that
each box contains a description of a world, and that the descriptions are of
the same world. It is the fact that each box bears multifarious semantic
relationships to the same things, though expressed in different "terminology"
and differently axiomatized, that grounds the regularity.
When I tried this thought experiment out on Danny Hillis, creator of the
Connection Machine, he thought immediately of a cryptographic "solution"
to the puzzle, and then granted that my solution could be profitably viewed
as a special case of his solution: "Al and Bo were using the world as a 'onetime
pad!'"—an apt allusion to a standard technique of encryption. You can
see the point by imagining a variation. You and your best friend are about to
be captured by hostile forces, who may know English but not much about
your world. You both know Morse code, and hit upon the following
impromptu encryption scheme: for a dash, speak a truth; for a dot, speak a
falsehood. Your captors are permitted to listen to you two speak: "Birds lay
eggs, and toads fly. Chicago is a city, and my feet are not made of tin, and
baseball is played in August," you say, answering "No" ( dash-dot; dash-dashdash)
to whatever your friend has just asked. Even if your captors know
Morse code, unless they can determine the truth and falsity of these sentences,
they cannot detect the properties that stand for dot and dash. This
variation could be added to our fable, for spice, as follows. Instead of shipping
the computer systems in the boxes to Mars, we put Al and Bo in the
boxes and ship them to Mars. The Martians will be as puzzled by them, if
they play the Morse-code prank, as by the computers, unless they draw the
conclusion (obvious to us, but we're not Martians) that these things in the
boxes are to be semantically interpreted.
The point of the fable is simple. There is no substitute for the intentional
stance; either you adopt it, and explain the pattern by finding the semanticlevel
facts, or you will forever be baffled by the regularity—the causal
regularity—that is manifestly there. The same moral, we have seen, can be
drawn about interpreting the historical facts of evolutionary history. Even if
you can describe, in matchless microdetail, every causal fact in the history of
every giraffe who has ever lived, unless you go up a level or two and ask
"Why?"—hunting for the reasons endorsed by Mother Nature—you will
never be able to explain the manifest regularities, such as the fact that
giraffes have come to have long necks, for instance. That is Dewey's point in
the quotation given earlier in this chapter.
At this juncture, if you are like many philosophers, you are attracted by the
claim that this thought experiment "works" only because boxes A and B are
artifacts whose intentionality, such as it is, is entirely derived and artifactual.
The data structures in their memories get their reference (if they