nothing moves

Zeno's Arrow
Zeno argued that the flight of an arrow is an example of motion. At any moment in time, the arrow either is where it is or it is where it is not. If it moves where it is, then it must be standing still, and if it moves where it is not, then it can't be there; thus, it cannot move.

Zeno's Arrow Paradox is similar to Heisenberg's Uncertainty Principle because Heisenberg argued that on the subatomic level, the only way to measure a system is to interfere with that system. That is, to observe a particle, one must bounce another particle off of it which affects the motion of the measured particle. The Heisenberg Uncertainty Principle says that if one wants to measure a quantity, say the position of an electron, the speed of that electron must inevitably be affected. We can no longer be certain about the speed. Thus, the very act of observation changes the system. We can be sure of the speed or the position but never both. Either the arrow is where it is or it is where it is not.
Back to the Paradox Page