6 Functions and Norms

Function ascriptions seem to involve normative questions. If the function of the governor
in a steam engine is to regulate the amount of steam fed to the cylinder, then that is what
it is supposed to do—that is what it is for. If the function of the pineal gland is to regulate
circadian rhythms, then that is what it is supposed to do. If things of a particular type have
a function, then some of them may perform this function better or worse than others do.
Wherever we can speak sensibly of better and worse, we are introducing not just an order-
ing relation among things but also an evaluation of this ordering relation. It is not just that,
say, x > y in some neutral sense but that x is better at something or for something than y
is. A good pruning knife does what a pruning knife is supposed to do better than a poor
pruning knife does. Things that are supposed to do something and don’t do it, or do it
poorly, are substandard or broken or just not properly applied. Things that have functions
can also malfunction. A malfunctioning kidney or carburetor is one that does not or cannot
do what it is supposed to do. When we speak of malfunctioning machines or organs, we
are appealing to normativity—to real or to metaphorical norms. These norms need not be
moral or even prescriptive in any strong sense, but they must involve at least some refer-
ence to a standard or type that supports evaluative judgments. A4 is a norm for typewriter
paper; a body mass index of 18 kg/m^2 is a norm for fashion models. If deviation from the
norm leads to the attribution of malfunction or some other evaluation, then the norm cannot
be a merely statistical norm. If the left hind leg of a water buffalo departs two standard
deviations from the norm for the number of freckles, it is not on that account a better or
worse water-buffalo leg. On the other hand, if a washing machine departs two standard
deviations from the norm for water consumption per kilo of laundry, it is on that account
a better or poorer washing machine.
How does normativity enter function ascriptions? Where do the norms come from?
Assuming that the facts adduced in analyzing function ascriptions are not normative, it
would seem that no number of factual propositions about functions or function bearers
could ground a norm—unless we have accomplished a naturalistic reduction of norms to
facts. (I ignore this angle here.) Where then does the normativity of function ascriptions
come from, and how is it justifi ed? Let us examine the three main interpretations of

Peter McLaughlin