Instrumentality

1. the quality or state of being instrumental.
2. the fact or function of serving some purpose.
3. a means or agency.

(“instrumentality,” Dictionary.com)

Instrumentality is a word that indicates that something serves a purpose or has a function. It can also be used to show that something is central to the operation of a system. For example, the instrumentality of the human experience in design. When used in this regard, the word shows that the human experience is central, or instrumental to design.