R. Mizoguchi et al. / A unifying definition for artifact and biological functions 133
uses some input to produce some output. Useful related notions (actually, roles) are conduit, operand,
medium, input/inlet and output/outlet.
3
An individual can play multiple roles (Mizoguchi et al., 2007)at
the same time; for example, a shaft in a car plays a conduit role and a medium role respectively to transfer
and to hold torque. Note that in this approach objects can be seen as systems of components (systemic
view). The idea is that the components of a system interact with each other and these interactions realize
a behavior of the system as a whole. A behavior is identified by looking at the changes caused on some
operand. In the case of the heating device described in the previous example, the heater’s behavior is
modeled as a change between the temperature of a fluid (the operand) at the inlet and at the outlet. This
view assumes that changes in real life are reducible to changes of physical (observable) qualities.
Scientists, like engineers and biologists, work with a simplified model of the processes in real-life.
Since real processes are rich of features and it is hard to build a perfect model, they select some aspects
and the relative properties which are relevant for their tasks and ignore the rest. Thus, they actually deal
with simplified representations obtained by considering a limited perspective of the ongoing change(s).
As we will see in the subsequent sections, such a model of behavior is adequate for understanding
functions.
4. Function context
The notion of context is a useful conceptual tool applied in different domains, from psychology and
sociology (Rogoff and Lave, 1984), to philosophy and linguistics (Lewis, 1980), from logic and rea-
soning (McCarthy, 1993; Ghidini and Giunchiglia, 2001) to human-computer interaction (Dey, 2001).
Contexts are regularly used and studied in interdisciplinary research (Brézillon et al., 2013). Notwith-
standing the large interest in the research community, no shared definition has emerged in the literature.
It is generally claimed that a context is like an environment or a situation, though these terms may have
quite different connotations (Dey, 2001).
Our goal is to investigate the notion of function with respect to a suitable notion of context. We assume
that the latter notion is available and use it as a primitive element that we specialize into the notion of
function context. For this purpose, we informally assume that a context C is a complex entity with (at
least) the following characteristics:
1. C existentially depends on (at least) one entity O. We highlight this by writing that the context C
is for O. For example, a heating context depends on a heat exchanger artifact, call it A
e
.Wethen
say that such a heating context is for A
e
(and perhaps for other entities as well).
2. For some entity O there exist multiple distinct contexts C
1
,...,C
n
. For example, heating and
cooling can be contexts for the same heat exchanger artifact A
e
.
3. There exists a context C which is context for different entities O
1
,...,O
m
. For example, a school
system is the context for both the teachers and the students of that school.
4. A context C for O identifies an entity S consisting of all the objects in C, including O,anda
description of a state (or set of states) of S. We call such a S the support of C. Typically, S is the
mereological sum of the entities in the context and in richer cases may include their relationships
as well. For example, the support of the cooling context is the sum of the heat exchanger artifact
(a radiator) with the connected pipes, pumps, fluids, heat generator(s) etc.
3
These and other notions are detailed in the device ontology presented in Mizoguchi and Kitamura (2009).