Characterizing functions based on phase- and evolution-oriented models

The purpose of this paper is to characterize some notions of function, mainly of artifacts in engineering and philosophy, from an engineering point of view. First, we distinguish some fundamental kinds of functions based on ontological distinctions. Then, using these kinds of functions, we present a phase-oriented model of artifact function along the product lifecycle. This model shows the kinds of functions generated by acts such as design, manufacturing and use. Then, we characterize the functions in the product life-cycle phases as a combination of those kinds of functions. Next, an evolution-oriented model of function is presented. This model shows how the fundamental notions of function have appeared along the evolutional history of creatures. Then, we characterize functions of artifacts, those of biological organs, and those of non-biological natural things.