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

418 THE EVOLUTION OF MEANINGS
hadn't the scientists been yearning for just such an explanation? Hadn't the
mystery of red and green strings now been entirely dissolved? Moreover,
now that it was dissolved, couldn't one see that there wasn't any hope at all of
explaining the causal regularity with which we began our tale without using
some semantical (or mentalistic) terms?
Some philosophers argued that, though the newfound description of the
regularity in the activity in the wire could be used to predict box B's
behavior, it was not a causal regularity after all. Truth and falsehood ( or any
of the adjusted stand-ins just considered) are semantic properties, and as such
are entirely abstract, and hence could not cause anything. Nonsense, others
retorted. Pushing button a causes the red light to go on just as certainly as
turning the ignition key causes your car to start. If it had turned out that what
was being sent down the wire was simply high versus low voltage, or one
pulse versus two, everybody would agree that this was a paradigm causal
system. The fact that this system turned out to be a Rube Goldberg machine
didn't show that the reliability of the link between a and red flashes was any
less causal. On the contrary, in every single case the scientists could trace out
the exact microcausal path that explained the result. 7
Convinced by this line of reasoning, other philosophers began to argue that
this showed that the properties red, green, and amber weren't really
semantical or mentalistic properties after all, but only imitation semantical
properties, mere as if semantical properties. What red and green were, really,
were very, very complicated syntactical properties. These philosophers
declined, however, to say anything further about just what syntactical
properties these were, or to explain how even young children could swiftly
and reliably produce instances of them, or recognize them. The philosophers
were nevertheless convinced that there had to be a purely syntactic
description of the regularity, since, after all, the causal systems in question
were "just" computers, and computers are "just" syntactic engines, not
capable of any real semanticity.
"I suppose," retorted Al and Bo, "that, if you had found us inside our black
boxes, playing a trick on you by following the same scheme, you would then
relent and agree that the operative causal property was genuine truth (or
believed truth, in any event). Can you propose any good reason for drawing
such a distinction?" This led some to declare that in a certain important sense
Al and Bo had been in the boxes, since they were responsible for creating the
respective data bases, as models of their own beliefs. It led others to deny
that there really were any semantical or mentalistic proper-
7. Some have argued that my account of patterns in Dennett 1991b is epiphenomenalistn
about content. This is my reply.
Blocking the Exits 419
ties anywhere in the world. Content, they said, had been eliminated. The
debate went on for years, but the mystery with which we began was solved.
3. BLOCKING THE EXITS
The tale ends there. Experience teaches, however, that there is no such thing
as a thought experiment so clearly presented that no philosopher can
misinterpret it, so, in order to forestall some of the most attractive misinterpretations,
I will inelegantly draw attention to a few of the critical details
and explain their roles in this intuition pump.
(l)The devices in boxes A and B are nothing but automated encyclopedias—not
even "walking encyclopedias," just "boxes of truths."
Nothing in the story presupposes or implies that these devices are
conscious, or thinking things, or even agents, except in the same
minimal sense in which a thermostat is an agent. They are utterly
boring intentional systems, rigidly fixed to fulfilling a single, simple
goal. They contain large numbers of true propositions and the inferential
machinery necessary to generate more truths, and to test for
"truth" by testing a candidate proposition against their existing data
bases. 8
Since the two systems were created independently, they cannot
plausibly be supposed to contain exactly the same truths (actually or
even virtually ), but, for the prank to work as well as I claim it did in
the story, we must suppose a very large overlap, so that it was highly
unlikely that a truth generated by A would not be recognized as such
by B. Two considerations, I claim, make this plausible: (a) Al and Bo
may live in different countries and have different native languages,
but they inhabit the same world, and (b) although there are kazil-lions
of true propositions about that world (our world), the fact that both Al
and Bo set out to create useful data bases—containing the information
that is relevant to all but the most recherche of human purposes—
would guarantee a high degree of overlap between the two
independently created systems. Although Al might know that at noon
on his twentieth birthday his left foot was closer to the North
8. Since these are just boxes of truths, no support is hereby given to the "language of
thought" hypothesis (Fodor 1975). I supposed that the world knowledge was stored in
a quasi-linguistic form just to make the storytelling easier (which is probably also the
reason motivating most researchers in cognitive science, who adopt the language-ofthought
hypothesis out of convenience!).