On Unifi cation: Taking Technical Functions as Objective 83
subjective. Adopting Searle’s theory is one way of doing that. I now end this contribution
by briefl y showing that the ICE theory can be generalized to a uniform function theory
that applies to also biological functions, providing one is ready to accept this second
option.
The original ICE theory has been, as I mention in section 5.5, proposed as an analysis
of technical functions by its reference to use plans, and the same holds for the ontological
version. In an exploration of how this limitation can be overcome, Wybo Houkes and I
have generalized the original ICE theory to a theory that can be taken as advancing a uni-
fying analysis of functional descriptions in technology, biology, and any other domain in
which functional descriptions are used (Vermaas and Houkes 2009). The generalized
central defi nition reads as follows:
The unifi ed epistemic ICE-function theory
An agent a justifi ably ascribes the capacity to φ as a function to an item x, relative to
a goal-directed pattern p for x and relative to an account A, iff:
I. the agent a has the capacity belief that x has the capacity to φ, in the execution
of p, and the agent a has the contribution belief that if this execution of p leads
successfully to its goals, this success is due in part to x’s capacity to φ;
C. the agent a can justify these two beliefs on the basis of A; and
E. the agents d who designated p have intentionally identifi ed x for having the capac-
ity to φ in p and for contributing by this capacity to the success of p, and have
intentionally communicated p to other agents l.
In this defi nition the notion of a use plan p for an artifact x has been replaced by the notion
of a pattern p that consists of a series of behaviors including behaviors of the item x, and
that is directed toward a goal. This pattern is singled out by agents, called the designators
d, who communicate the pattern to other agents, called laypersons l, with the aim to
provide information to those laypersons about the existence of this pattern and about how
item x contributes by its capacity to φ to the effectiveness of the pattern to lead to its goals.
In technology, the designators are designers and the laypersons are users. In biology, the
designators are those who identifi ed specifi c biological behaviors as making up goal-
directed biological patterns—for example, William Harvey, who considered the circulation
of blood and saw the pumping capacity of the heart as contributing to this circulation—and
the laypersons are other biologists who are informed about these patterns and the contrib-
uting roles of the partaking items. And in, say, sociology, the designators are those who
identifi ed social behavior as making up goal-directed sociological patterns, and the lay-
persons are those who learn about these patterns.
This generalization is meant primarily as an exploration of how the ICE theory may
fare when applied within, say, biology. The unifi ed epistemic ICE-function theory has
some advantages. It can, for instance, make sense of biological functional descriptions that
do not rely on evolutionary theory, such as the one made by Harvey, and are less well