Abstract
Aiming at clearer semantics of notion of function, this article discusses some ontological issues about function such as what the existence of function depends on, how a function inheres to an artifact, and when a function exists and disappears. Firstly, we investigate some ontological distinctions of functions such as actual function and capacity function. Secondly, we propose an ecological model of function that explains how the existence of instances of function is changed by engineering tasks such as design and manufacturing. Thirdly, we discuss differences of functions of artifacts and natural things. Lastly, we try to explain a definition of biological functions and its differences.
