218 Yoshinobu Kitamura and Riichiro Mizoguchi
We are currently investigating the use of the generic categories of function shown in
fi gure 12.3 as a “reference ontology” (its computational implementation was reported in
(Kitamura, Takafuji and Mizoguchi 2007)) for translation of functional vocabularies (cur-
rently between Functional Basis (Hirtz et al. 2002) and ours) (Ookubo et al. 2007). Such
a generic reference ontology of function, we believe, can clarify the ontological differences
between functional vocabularies and thus improve the interoperability of functional knowl-
edge. Furthermore, aiming at a computational basis with clearer semantics for discussion
on the ontological nature of functions, we are also investigating a computational model
of functions using the standardized ontology representation language OWL (Kitamura
2008).
Acknowledgments
The authors are most grateful to Professor Barry Smith of University at Buffalo for
his extensive discussions that helped us to clarify our defi nition of function in
section 12.2. The authors thank the anonymous reviewer(s) for their valuable comments.
The authors would also like to thank Yusuke Koji, Kouji Kozaki, Munehiko Sasajima,
Eiichi Sunagawa, Naoya Washio, and Masanori Ookubo for their contributions to this
work.
Appendix: A Brief Comparison with Other Notions of Context of Function
Perlman points out the importance of “context” (this volume). He mainly discusses
environmental contexts for functioning. As he points out, Cummins also emphasizes
a function’s dependence on an “analytical context” in the causal-role functional analysis
as follows: “To ascribe a function to something is to ascribe a capacity to it which is
singled out by its role in an analysis of some capacity of a containing system” (Cummins
1975: 765). In this defi nition, a function of a component is based on the component’s
causal role for a capacity of a containing system. In our defi nition, a component function
is a role of a behavior for operands under the context of the system in which the component
is embedded. In this context, there are causal relations among the components’ functions
and an is-achieved-by relation among the components’ functions and the system’s
function.
Our external function context is based on the designer’s or user’s intention. In this sense
our defi nition can be regarded as a kind of “goal-contribution theory” based on intentional
states in the “recent past backward-looking reductionist category” in Perlman’s categoriza-
tion of defi nitions of functions (Perlman 2004). Among others, Boorse defi nes a function
as a role as follows: an “artifact function [is]... an object’s role in a human goal-directed
activity” (2002: 68).