A Taxonomy of Functions in Gellish English

This paper sketches a possible route to overcome the problems of ambiguous use of the function notion in engineering. Our method is to implement functional descriptions in a formal language, viz. Gellish English, which is standardized structured English defined in STEPlib (based on ISO 10303221 (AP221) and ISO 15926). Our main results are twofold. First, we provide a formal taxonomy in Gellish English of three different and important senses of the term function: the SE-function featuring in systems engineering colloquially characterized as the “actions carried out to achieve the system’s objectives”; the KB-function, which is mainstream in knowledge base architectures as “being the performer of the activity,” and the C-function in philosophy as “the capacity of the performing object.” Second, we show how to prune philosophical accounts of functions down to manageable detail for practical engineering applications.