 An immediate concern is why Zeno is justified in assuming that the arrow is at rest during any instant. It follows immediately if one assumes that an instant lasts 0s: whatever speed the arrow has, it will get nowhere if it has no time at all. But what if one held that the smallest parts of time are finite—if tiny—so that a moving arrow might actually move some distance during an instant? One way of supporting the assumption—which requires reading quite a lot into the text—starts by assuming that instants are indivisible. Then suppose that an arrow actually moved during an instant. It would be at different locations at the start and end of the instant, which implies that the instant has a ‘start’ and an ‘end’, which in turn implies that it has at least two parts, and so is divisible, contrary to our assumption. (Note that this argument only establishes that nothing can move during an instant, not that instants cannot be finite.)