Didascalicon, Book I (chapters 2-13): the origin of the arts and the division of philosophy
Chapter XI. What nature is
Since we have already named nature so often: although, as Tully says, “it is difficult to define nature,” nevertheless the signification of this word seems not to be passed over in complete silence. Nor, because we cannot say everything we wish, ought we to keep silent about what we can. The ancients are found to have said many things about nature, but nothing so that nothing seems to remain. Yet as far as I can conjecture from their sayings, they were accustomed to use the signification of this word chiefly in three ways, assigning to each its own definition.
In the first way, by this name they wished to signify that archetypal exemplar of all things which is in the divine mind, by whose reason all things were formed; and they said that nature is the primordial cause of each thing, from which it has not only being but such being. To this signification the following definition is assigned: “Nature is that which gives to each thing its being.” In the second way they said that nature is the proper being of each thing, to which signification this definition is assigned: “Nature, informing each thing, is called its proper difference”; according to which signification we are accustomed to say that all heavy things tend toward the earth, light things seek the heights, fire burns, water wets. The third definition is this: “Nature is an artificer fire, proceeding from a certain power to produce sensible things.” For the physicists say that all things are produced from heat and moisture. Hence Virgil calls Oceanus father; and Valerius Soranus says in a certain verse about Jove, signifying the ethereal fire:
Almighty Jupiter, discoverer of things and of kings, Progenitor and mother of the gods, one and the same.