How Biological, Cultural, and Intended Functions Combine 63
ined effect the planned object should have in the foreseen conditions. Actually, inventing
includes many different aspects; it is not just a case of drawing and calculating with pen
and paper. I argue that some testing procedures in fact should be viewed as giving rise to
selected functions and that consequently, in the invention phase, too, the situation is not
as simple as one might expect. As explained at the beginning of the article, a selected
function refers to a real property (the effect that some Xs had, which led to the selection
of Xs against variants), while an intended function refers to a mental content relative to
the Xs (the effect that rational humans think some Xs, at least, will have in determined
circumstances). Now the testing of prototypes has to do with real effects, not with imagined
effects.
Suppose that several engineers have worked on airbag triggers for cars and have come
up with different models. Airbag triggers must be fast and accurate, they must not trigger
too late, but they must not be too sensitive and trigger when the car is passing over a
pothole or when the brakes are sharply applied. Suppose the different models were submit-
ted to an appropriate battery of tests in a car crash test lab. Suppose that one of the models,
let us say the M12, came out of the battery of tests victorious. Then the effect for which
M12 devices will be put in cars as car airbag triggers is real; in fact this effect showed in
tests. Better still, it showed in a situation of selection, the situation of comparative tests.
Consequently a classical SEL defi nition of function applies with no diffi culty. “M12 has
the function of triggering a car airbag” can be interpreted as meaning “M12 was selected
for its car-airbag-trigger effect.” In fact it was selected because it demonstrated a better
car-airbag-trigger effect than its competitors in certain real contexts. Before we investigate
to see if this defi nition of the M12 function really hinges on a car-airbag-trigger effect,
let us fi rst clarify what the point of the whole argument is. We want to show that, contrary
to widespread opinion, there is no straightforward answer to the question “What is the
nature of the car airbag function of M12?” In particular, the current etiological theories
do not deliver the simple single answer, an intended function. According to those theories,
M12 should in fact have an intended car-airbag-trigger function before the fi rst battery of
tests, but a selected one after it. Let us now resume our investigation of the above SEL
defi nition.
Is the selective context of the tests really a selective context relative to car properties?
The classifi cation of an effect depends in fact on the context. Selection is necessarily rela-
tive to car-something effects if the different models are tested in real-life situations by
being installed in cars that have been sold to ordinary consumers. When the selective
context is artifi cial, however, the categorization becomes more problematic. An intuitive
grasp of the problem is made easier by considering the two ends of the prototype-testing
spectrum. At one end, there are the tests made in a very sophisticated car-crash test lab of
a big fi rm where real cars are sometimes used and where the conditions of real-life car
driving are very well simulated. At the other end of the spectrum there are the tests made
by amateurs with poor resources. Let us suppose that a group of experts considering some