Another quality is needed to do something (i.e., to be active in a certain way or to make something, as distinct from engaging in the activity of making it). This quality is art or applied science, which can be defined as the disposition or characteristic of making things according to the guidance of true wisdom, and as such is concerned with the realm of coming-to-be (i.e., with determining how something which is capable either of being or not being may come into existence). Things which exist or come into being by necessity and things produced by nature (i.e., things which contain their own sources of motion) are not within the sphere of art. It deals with production not action, and is subordinate to practical wisdom, which is the guide for using things produced by art. In the sense intended here, the word "art" pertains to both aesthetic and utilitarian production.