In a recent review of Prof. W. B. Smith’s “Infinitesimal Calculus,” fault is found with his statement that “In all strictness there can be no motion at an instant, and hence no speed (or velocity) at an instant. The concept of speed (or velocity) or motion will not combine with the concept of instant (or point of time) to form a compound concept.” Part of the reviewer’s criticism is as follows: “If we allow that motion at an instant is impossible, how are we to escape from Zeno’s paradoxical conclusion that all motion is impossible? How can I move from one place to another during a minute, say, if at every instant of that interval motion is impossible?”