Krohs_00_Pr.indd

(Jacob Rumans) #1

26 Mark Perlman


attention to context. This can lead to an over-reliance on function, when considering the
context would do most of the explaining.
A well-known account of function comes in Dretske (1986), who invokes biological
functions in an attempt to solve the problem of misrepresentation. His teleological account
of misrepresentation rests on a relatively simple claim: a representation M means that p
if and only if it is M’s function to indicate the condition of p. In his view, functions dis-
tinguish events that, for adaptational reasons, are supposed to occur (and thus determine
content) from those that merely happen to occur. When a token instance of M occurs
because of a condition it is its function to represent, M correctly represents that condition.
When a token of M occurs because of a condition other than one it is M’s function to
indicate, M fails to perform its function and is a misrepresentation. Dretske (1986: 26)
illustrates his point with an oft-cited biological example:


Some marine bacteria have internal magnets (called magnetosomes) that function like compass
needles, aligning themselves (and, as a result, the bacteria) parallel to the earth’s magnetic fi eld.
Since these magnetic lines incline downwards (towards geomagnetic north) in the northern hemi-
sphere (upwards in the southern hemisphere), bacteria in the northern hemisphere, oriented by their
magnetosomes, propel themselves towards geomagnetic north. The survival value of magnetotaxis
(as the sensory mechanism is called) is not obvious, but it is reasonable to suppose that it functions
so as to enable the bacteria to avoid surface water. Since these organisms are capable of living only
in the absence of oxygen, movement towards geomagnetic north will take the bacteria away from
oxygen-rich surface water and towards the comparatively oxygen-free sediment at the bottom.
Southern hemispheric bacteria have their magnetosomes reversed, allowing them to swim towards
geomagnetic south with the same benefi cial results. Transplant a southern bacterium in the North
Atlantic and it will destroy itself—swimming upwards (towards magnetic south) into the toxic,
oxygen-rich surface water.


Dretske invokes the complexity of the organism to deal with this problem: with more
complex organisms, organisms capable of learning, we are entitled to the more liberal
function of oxygen-indication, whereas in less complex organisms without the resources
for expanding their information gathering resources, the more conservative magnetic-fi eld-
indication is the function.
Millikan’s (1989a, 1989b) answer to this indeterminacy problem is that, from the
standpoint of the “consumer” of the representation, the content is clear. The consumer
needs only to have a representation that will lead it to behave in the right way. By
that point in the organism’s physiology, the history of the representation does not
make a difference to the effect that consuming the representation will have. Thus
Millikan’s position is that, from the consumer end, the representational content is
univocal and determinate—the direction of oxygen-free water (not magnetic north).
This content assignment has the transplanted organisms misrepresenting their surround-
ings, as their environment does not have oxygen-free water in that direction, and this kills
them.

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