 The first eleven sophisms deal with the process of whitening, in which the motion of alteration is conceived as a successive entity extrinsically limited at its beginning and end. There is no first instant of alteration, claims Kilvington, but only a last instant before the alteration begins; likewise, there is no last instant of alteration, but only the first instant at which the final degree has been introduced. There is no minimum degree of whiteness or speed gained in motion, but rather smaller and smaller degrees ad infinitum down to zero, since the qualities change continuously. Integers are potentially infinite because one can always find a higher integer, but not actually infinite since there is no single infinite number. In Kilvington’s view, since any continuity—e.g., time, space, motion, heat, whiteness—is infinitely divisible, it can be spoken of quantitatively and measured in terms of infinite sets of integers. The subjects of sophisms 29–44 reveal Kilvington’s special interest in local motion with respect to causes, i.e., active and passive potencies, and effects, i.e., time, distance traversed, and speed in motion. He considers both uniform and difform motion caused by voluntary agents and points out the questionable measure of instantaneous speed through the comparison of speed in uniform and accelerated motion (see Kretzmann 1982).