  Note, however, that even if we endorsed the exhaustiveness of the dichotomy of natural and forced motions, and accepted the thesis that simple bodies possess a unique natural motion (De caelo 1.2, 269a8–9), we would not need thereby to accept  Aristotle’s further major claim, that  natural and forced motions come in pairs of opposites, with the  result that if a motion is contrary to the nature of an entity, the  opposite motion will be its natural motion (De caelo 1.2,  269a9–18).  Where there is room for some more complex relationships  among the targets of changes than a simple opposition along an axis  of a single dimension—and this is eminently so between locomotions along rectilinear and circular paths respectively—there can be several forced  translations in contrast to the single natural motion of the elements endowed with rectilinear natural motion, as Aristotle  also admits in some passages of the De caelo (see 1.2,  269a30–b2 and 269b10–12). 