A mathematician has potentially debunked one of the most enduring myths in architectural history through his analysis of optical illusions in relation to the Parthenon, the iconic Greek temple situated above Athens.
For over two millennia, scholars have been captivated by the structure on the Acropolis, praising its creators for their innovative application of geometric principles. The building’s gentle curves are often said to counteract visual distortions that could detract from the Parthenon’s aesthetic precision.
However, after conducting an extensive study and employing various mathematical models, Professor Alain Goriely from the University of Oxford has reached a surprising conclusion: the optical phenomena that the curves are believed to address are either unfounded or nearly imperceptible, suggesting that these illusions are illusions themselves.
In his research, Goriely traces the origin of this myth back to Vitruvius, a Roman architect and engineer from the first century, who documented the Parthenon more than four centuries after it was built. His writings eventually became influential in architectural literature, solidifying the myth as a widely accepted fact. Even contemporary AI chatbots perpetuate this narrative. Goriely remarked, “I believe it could be the oldest myth we have, aside from those related to religion.”
One prevalent assertion challenged by Goriely pertains to the Parthenon’s base, or stylobate. Instead of being perfectly horizontal, measurements reveal that the sides of the base curve upward, rising by 6 centimeters in the center. Vitruvius claimed that this curvature was intended to counteract an illusion that would create the appearance of sagging in the middle.
This sagging effect has been linked to two different visual phenomena. The first posits that long, straight lines naturally seem to dip in the center; however, Goriely found no supporting evidence for this theory.
The second explanation involves the Parthenon’s marble columns, which are said to create an illusion based on the Hering illusion, where parallel lines may appear curved when intersected by others. Yet, Goriely argues that this illusion is most effective with intersecting lines at acute angles, while the Parthenon’s columns are too vertical to produce the effect, and there is insufficient evidence to suggest it operates in three dimensions.
Another commonly held belief is that the slight bulges in the columns, known as entasis, rectify an illusion that would make them seem too slender in the midsection. Once again, Goriely found no evidence to support this claim. Furthermore, the bulge of merely 18 millimeters is hardly noticeable from typical viewing distances.
In his paper, Goriely critically evaluates and dismisses other alleged “optical corrections,” admitting that he became somewhat engrossed in piecing together the evidence. He speculates that the architects of the Parthenon may have had alternative motives for these design features.
For instance, the curvature of the base may have aided in preventing rainwater accumulation, and the design of the columns could have been intended to evoke a sense of natural beauty for the ancient Greeks, as he notes in Royal Society Open Science.
The reason for the myth’s persistence remains unclear, though Goriely suggests that the perception of ancient Greece as a highly sophisticated and brilliant civilization plays a significant role in its longevity.
In a unique conclusion for an academic paper, Goriely encourages readers to step outside and experience the city firsthand. “Trust your own eyes, question what you see, and determine for yourself if the theory of optical corrections holds true,” he advises.
Professor Frank Salmon, who specializes in the history of classical architecture at the University of Cambridge, remarked that many experts have long been wary of Vitruvius’s interpretations, acknowledging the risks involved in treating his texts as definitive accounts of architectural practices in ancient Greece, particularly given the loss of numerous Greek writings on temple architecture that he claimed to have consulted.
