Definition: Will is a property on account of which goodness, greatness, duration etc. are desirable; and it is a property whereby good, great etc. substantial beings are willing.
Distinction and clarification: now the One supreme will itself is a being both substantial and willing; as a substantial being, it originates what is willed by it so that the One who wills and what is willed both exist as One selfsame natural essence of will. Beyond this voluntary principle, there can be nothing loftier in the essence of will where willer and willed can participate no further in the goodness etc. of will, within the essential nature of the goodness, etc. of will. Willer and willed give rise to the act of willing on account of the selfsame form of both willer and willed, and this form is innate to the essence of will. The said principles are sought by all other appetitive principles, since this supreme will is the cause that produces all other appetites as its effects.
Nature: the inherent essential correlatives of will are, as was shown: the willer, willable and their willing whence follows what is willed, loved or desired.
Without the natural essence of will and its likenesses manifested in various appetites, desire would be entirely subject to some purpose not its own.
As he applies this principle to the Art, or to the work of this Art and uses it with the other principles of this Art, the artist forms and regulates his act of willing and directs it to what is good, great, etc. to find out what he wants to know more quickly and truly. Now as the willer and the willed or desired object approach the natural essence of will and goodness more and more closely, the intellect improves its understanding and grasp of what it wants and knows. When the artist thus considers the supreme willing One and what is willed by Him, he raises his consideration aloft to the One whom he willingly considers, whence he draws the power to consider how things are willed and caused; for these reasons, will must be included as a principle of this Art.