The illusion of illusions: there are no optical corrections in the Parthenon

Abstract One of the oldest and most enduring myths in human history is the belief that the Parthenon was cleverly designed with various curved structures and sizes in order to correct visual illusions and thereby make it appear straight and regular. The myth of optical corrections has its origin in the writings of Vitruvius more than 2000 years ago and was renewed in the nineteenth century when curved profiles were carefully measured. At least 12 different optical corrections have been proposed, all following the same basic principle. The myth remains widely accepted despite an absence of direct historical or experimental evidence. This paper analyses these corrections scientifically and argues that the proposed illusions are either unsupported by evidence or too small to have a perceptible effect under typical viewing conditions.