In Scholastic manuals, natural philosophy (physics) was typically defined as “the science of natural bodies, in so far as they are natural.” This means that natural philosophy in the Peripatetic tradition did not deal with artifacts qua artificial. It did not share the concerns of the mechanical arts in general or of mechanics in particular. Up to and including Descartes’ time, mechanics in one sense was concerned with the construction and operation of machines and other artifacts designed to move terrestrial things against nature (contra naturam) and for human ends. However, from the time of the Mechanica, written by a member of the Peripatetic school (Strato of Lampsacus?), and of Pappus's Collections (book 8), mechanics was also the theoretical discipline that dealt mathematically with problems relating to the construction and use of machines. Mechanics in this sense was often also called the science of weights, or statics. Before a mechanical device begins to act on something, there is stasis, a state of rest in which opposing forces are in equilibrium before being unbalanced by an external force. In statics, one calculated the relative strengths of such forces to account for states of equilibrium (equal weights on a balance) and of disequilibrium (budging a boulder with a lever). In the Renaissance, which saw the rediscovery of the Mechanica, mechanics became a “middle science” operating between mathematics and physics, in which the operations of machines were treated in a mathematical way (Laird 1986). In the Collegio Romano there arose the important question of whether this middle science could be fully integrated into the natural philosophy of the Scholastics to produce a true middle science that was not subalternated to mathematics (Wallace 1984, 202–7). The question is reflected in a professional contrast of the period: treatises on mechanics were written by mathematicians or engineers, not by philosophers within the Scholastic tradition. Not until the Newtonian eighteenth century did the question receive a positive answer, though one that was seriously qualified by considerations that cannot be addressed here.