 In his Triumph of Philosophy, Taurellus accepts the traditional claim that the elements (earth, water, air, fire) are the basic constituents of the natural world. However, he develops an intricate argument for denying the received view that prime matter enters into the constitution of elements (see Blank 2014). Thereby, he offers a reinterpretation of the nature of the elements. The argument starts with a consideration of the motivation for introducing the notions of form and prime matter. As he describes it, the motivation arises out of the view that in natural things there are contrary properties: active properties such as the capacity of bringing forth changes in other things, and passive properties such as the capacity of undergoing change through the agency of other things. If these properties are understood as contrary, then they seem to require two different origins. For this reason, the active properties of natural things were seen as requiring the existence of forms, while the passive properties of natural things were seen as requiring the existence of primary matter (PT: 202).