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

412 THE EVOLUTION OF MEANINGS Two Black Boxes 413
to give meaning a proper causal role. This is an idea we have seen in an
earlier incarnation, as the worry about minds' being mere effects, not originating
causes. If meaning gets determined by the selective forces that
endorse certain functional roles, then all meaning may seem, in a sense, to be
only retrospectively attributed: what something means is not an intrinsic
property it has, capable of making a difference in the world at the moment of
its birth, but at best a retrospective coronation secured only by an analysis of
the subsequent effects engendered. That is not quite right: an engineering
analysis of the two-bitser, newly arrived in Panama, would permit us to say
what roles the device, so configured, would be good for, even if it had not yet
been chosen for any role. We could reach this verdict: its acceptance state
could mean "quarter-balboa here now" if we put it in the right environment.
But of course it could also mean lots of other things, if placed in other
environments, so it won't mean any one of them until a particular functional
role for it gets established—and there is no threshold for how long it takes a
functional role to become established.
That is not enough for some philosophers, who think that meaning, so
construed, doesn't pull its weight. The clearest expression of this idea is Fred
Dretske's (1986) insistence that meaning must itself play a causal role in our
mental lives in a way that meaning never plays a causal role in the career of
an artifact. Put this way, the attempt to distinguish real meaning from
artificial meaning betrays a yearning for skyhooks, a yearning for something
"principled" that could block the gradual emergence of meaning from some
cascade of mere purposeless, mechanical causes, but this is (you must
suspect) an optional and tendentious way of putting it. As usual, the issues
are more complex than I am showing, 4 but we can force the key points into
the open with the help of a little fable I recently devised precisely to give
these philosophers fits. It works. First the fable, and then the fits.
2. Two BLACK BOXES 5
Once upon a time, there were two large black boxes, A and B, connected by
a long insulated copper wire. On box A there were two buttons, marked a
and ß, and on box B there were three lights, red, green, and amber. Scientists
studying the behavior of the boxes had observed that whenever you
4. Dretske and His Critics (McLaughlin, ed, 1991) is devoted largely to this issue.
5. This began as an impromptu response to Jaegwon Kim's talk at Harvard, November 29,
1990: "Emergence, Non-Reductive Materialism, and 'Downward Causation,' " and evolved
under the persistent rebuttals of Kim and many other philosophers, to whom I am
grateful.
FIGURE 14..1
pushed the a button on box A, the red light flashed briefly on box B, and
whenever you pushed the (ß button on box A, the green light flashed briefly.
The amber light never seemed to flash. They performed a few billion trials,
under a very wide variety of conditions, and found no exceptions. There
seemed to them to be a causal regularity, which they conveniently summarized
thus:
All a's cause reds.
All ß's cause greens.
The causation passed through the copper wire somehow, they determined,
since severing it turned off all effects in box B, and shielding the two boxes
from each other without severing the wire never disrupted the regularity. So
naturally they were curious to know just how the causal regularity they had
discovered was effected through the wire. Perhaps, they thought, pressing
button a caused a low-voltage pulse to be emitted down the wire, triggering
the red light, and pressing button (3 caused a high-voltage pulse, which
triggered the green. Or perhaps pressing a caused a single pulse, which
triggered the red light, and pressing ß caused a double pulse. Clearly, there
was something that always happened in the wire when you pressed button a,
and something different that always happened in the wire when you pressed
ß. Discovering just what this was would explain the causal regularity they
had discovered.
A wiretap of sorts on the wire soon revealed that things were more
complicated. Whenever either button was pushed on box A, a long stream of
pulses and gaps (ons and offs, or bits) was sent swiftly down the wire to box
B—ten thousand bits, to be exact. But it was a different pattern each time!
Clearly, there had to be a feature or property of the strings of bits that
triggered the red light in one case and the green light in the other. What
could it be? They decided to open up box B and see what happened to the