 In chapter IV of the Regulae (De incipit et desinit) Heytesbury poses and analyzes in great detail cases in which any process, thing, or state may be said to begin or cease to be. He begins with possible expositions of the terms “beginning” (incipere) and “ceasing” (desinere) in a way that uncovers certain paradoxical properties of the temporal continuum. “Beginning” may be expounded by positio of the present (i.e., by the positing of existence in the present instant) and remotio of the past (i.e., by denial of existence in the past), meaning that in the present instant a thing or a process is, and immediately prior to the present instant it was not. “Beginning” may be also expounded by remotio of the present and positio of the future, meaning that in the present instant a thing or a process is not, and immediately after the present instant it will be. Likewise, “ceasing” may be expounded in two ways, either by remotio of the present and positio of the past, meaning that in the present instant a thing or a process is not, and immediately prior to the present instant it was, or by positio of the present and remotio of the future, meaning that in the present instant a thing or a process is, and immediately after the present instant it will not be. Heytesbury offers a number of sophisms involving the limit-decision. One of them is particularly interesting since it clearly exhibits Heytesbury’s remarkable skill in solving problems of instantaneous motion and time without the symbolic techniques of calculus. Heytesbury poses a case in which both Plato and Socrates begin to move from rest at the same instant, but Plato starts to move with a constant acceleration and Socrates with an acceleration which starts at zero degree and increases uniformly with time. He concludes that “both Socrates and Plato infinitely slowly begin to be moved, and yet Socrates infinitely more slowly begins to be moved than Plato” (Wilson 1960: 54, [RSS] 1494: fol. 26vb). As Wilson proves, the conclusion is an effect of comparison of two infinitesimals of different order.