The Infinite Tortoise: The Curious Thought Experiments of History's Great Thinkers

From Plato's Cave to Descartes' Demon, and from Zeno's paradoxes to Hilbert's Hotel, great thinkers have used thought experiments and paradoxes to try and work out complex ideas in the simplest way possible. Perhaps the most famous thought experiment is that of Zeno's Achilles and the tortoise. If both Achilles and the tortoise move at constant speed, why will Achilles never catch up with the tortoise when the tortoise starts ahead of him? Zeno argues that when Achilles reaches the point where the tortoise started the race, the tortoise will have already moved on. And as Achilles runs on to where the tortoise was last, when he reaches that point the tortoise has moved again. Therefore Achilles will never catch up with the tortoise as the distance he must run gets smaller and smaller and each time he has less and less time to run.