82 Pieter E. Vermaas
Second, in the case that an artifact is in a state in which it has the capacity to φ corre-
sponding to its function but is not actually capable of exercising it, the artifact may be
called malfunctioning if the reparation and maintenance needed to bring the artifact to a
state in which it is capable of exercising the capacity is not part of the use plan for the
artifact; in all other cases the artifact cannot be called malfunctioning. By this second
distinction a car that has run out of petrol is not malfunctioning since it is part of the car’s
use plan that its user—the driver—regularly fi lls it up with petrol. A car with a broken
starting motor is, however, malfunctioning, since changing that motor is not part of the
car’s use plan.
With these distinctions in place, the ontological ICE theory can be taken as accommo-
dating the phenomenon of malfunctioning: an artifact that is—temporarily—not capable
of exercising the capacity corresponding to its ontological ICE function but that can be
brought back into a state in which it can exercise that capacity by feasible “non-use-plan
repair or maintenance,” has this capacity and thus has this capacity as its function in the
ontological ICE theory. Note that the original epistemic ICE theory can with this new
characterization of malfunctioning accommodate this phenomenon in a much broader way.
The agents ascribing a capacity as a function to an artifact can with the new characteriza-
tion, for instance, simultaneously believe that the artifact has a capacity, justify this with
an account, but also acknowledge that they believe that the artifact is not capable of exer-
cising that capacity.
A fi nal note is that this characterization turns malfunctioning into a phenomenon that
is based on, fi rst, a normative distinction between reparation and maintenance that is
technologically and economically feasible, and reparation and maintenance that is not,
and, second, on a division of labor between users of artifacts and expert technologists: an
artifact malfunctions if it needs repair and maintenance that is feasible for expert technolo-
gists but that is not a task of its users.
5.7 A Unifi ed ICE-Function Theory
Having argued that the ontological ICE-function theory can accommodate malfunctioning,
it can be proposed as an acceptable theory of technical functions. With this theory one can
then argue that technical functions are epistemically objective and ontologically subjec-
tive, showing that the difference between biological and technical functional descriptions
becomes merely that biological functions are ontologically objective whereas technical
functions are ontologically subjective. This last difference seems to be one not to deny.
One option for this denial is to opt for the ontological version of Cummins’s theory, since
in that theory technical functions are also ontologically objective. Yet this option is blocked
when one requires that a function theory should accommodate malfunctioning. Another
option may be to bridge this last difference by taking biological functions as ontologically