Lesson · 4 min Stretch
The Arrow
In one line At any instant a flying arrow is just where it is. Zeno asked how a string of still moments makes motion.
Zeno’s arrow paradox asks about a single moment. At any instant, a flying arrow occupies a space exactly its own size. In that instant it does not move, since there is no time for it to move in.
But the whole flight is made of instants. If the arrow is at rest in each one, and time is nothing but instants, then the arrow is at rest the whole time. Motion seems to vanish.
Aristotle answered that time is not built from indivisible instants, any more than a line is built from points. Modern physics gives the arrow a velocity at each instant, defined by how its position changes around that moment. Motion belongs to the pattern across times, not to one frozen frame.
Go deeper
The arrow raises a question about photographs and data. A single snapshot of a busy street shows cars standing still. Speed cannot be read off one frame; it shows in the comparison between frames. Bertrand Russell defended an “at-at” theory of motion: to move is simply to be at different places at different times, with nothing more to it.
The single frame
A sports photo shows a sprinter in midair, perfectly still. A viewer jokes that she is not running at all.
A coach answers with the video. Run frame by frame, each image is still, but her position changes from one to the next. The running is in that change. A single frame is the wrong place to look for it.
Try this today When a claim rests on one moment, such as a single poll, ask what the trend over time shows.
Cite or share this lesson
A plain reference you can paste into notes or an essay:
Quest2Reason. “The Arrow.” https://quest2reason.com/learn/lesson/the-arrow. Accessed 13 November 2026.
Sources
- Internet Encyclopedia of Philosophy, “Zeno’s Paradoxes” — Covers the arrow, the standard modern reply using instantaneous velocity, and Russell’s at-at theory of motion.
- Stanford Encyclopedia of Philosophy, “Aristotle’s Natural Philosophy” — Explains Aristotle’s account of time and continuity, which he used against the arrow.
- Aristotle, Physics, Book VI, part 9 (Hardie and Gaye translation) — Reports the arrow and answers that time is not made of indivisible moments.
- Stanford Encyclopedia of Philosophy, “Zeno’s Paradoxes” — Covers the arrow alongside the other paradoxes of motion and the modern replies.