Life is much like the philosophical questions posed by the Greek story of the ship of Theseus. This particular problem is known as the sorties paradox. The ship of Theseus is a thought experiment, rooted in contemplation, that raises the question of whether an object that has had all of its components replaced remains fundamentally the same object. The concept is one of the oldest in Western philosophy, having been discussed by Heraclitus and Plato by c. 500–400 BC.