Response to Barnard (2014)

    Two questions that arise from Barnard's (2014) insightful article on "Surveying in Ancient Egypt" are: (1) Since "the basis for the Ancient Egyptian unit of length was the cubit, the length from the elbow to the tip of the middle finger," whose forearm was used to establish the cubit? and (2) Was Eratosthenes's calculation of the Earth's circumference, which implied the Earth was spherical, considered a radical idea at the time? The first question intrigues me because the answer could reveal which person, class, or gender held influence in defining standards—similar to how the "foot" was once based on the length of an English king's foot rather than the population average. Given that the tombstone mural depict people from different social classes, including children, participating in surveying, I wonder who had the authority to have their arm served as the standard unit of measurement.

    The second question is similar in nature to the controversy sparked by Galileo Galilei's 17th-century discovery that the Earth orbits the Sun. Did Eratosthenes’s conclusion that the Earth was spherical, with a measurable circumference, challenge any dominant religious or cultural beliefs, such as a concept of heaven existing above a flat Earth?

    What surprised me most was the Ancient Egyptians' understanding of the irrational number √2, which they estimated as nearly equivalent to 19.5 fingers (again, whose fingers?). Despite lacking precise tools, they approximated a value remarkably close to what we now know as √2. This raises an interesting question: have humans always been drawn to geometric forms like the square, leading to a natural curiosity about the length of its diagonal?