Yesterday, Twitter got a new name: X.
Elon Musk’s fascination with the number isn’t new. In 1999, Musk launched “x.com,” a financial services company that eventually became PayPal.
Musk isn’t alone. As a society — and especially in the tech world — we’re obsessed with X. X-Men. X-rated. X marks the spot. Xmas. Xbox.
The origin of our obsession with X, especially amongst techies, might be traced back to math, where X is often used to represent unknowns. It’s something to solve for, a mystery to figure out. In the 9th century, Persian mathematician Muhammad al-Khwārizmī — the inventor of algebra — used “shay” (the Arabic word for thing) to refer to unknowns. When his book was translated into medieval Spanish, “shay” became “xei,” which in some cases, might’ve been abbreviated as X.
X was independently chosen to represent unknowns in 1600s France when philosopher René Descartes selected the last three letters (x, y, and z) to represent unknown values. X, in turn, was Descartes’ go-to symbol for variables in his 1637 book La Geometrie.
However, our obsession with X pre-dates algebra and the alphabet. According to linguist Jamin Pelkey, our obsession with the letter stems from our bodies.
When we push our body to its extremes — both arms and both legs outstretched — we form an X. This is an “embodied X,” more commonly known as the “spread eagle.”
Perhaps the most notable example of the embodied X is the Vitruvian Man, a depiction of a man inscribed within a circle and a square. The depiction, while made most famous by da Vinci, was first proposed by Roman engineer Marcus Vitruvius Pollio in 25 BCE. Vitruvius wrote of the visual:
“Symmetry arises from proportion. … For measuring from the feet ot the crown of the head, and then across the arms fully extended, we find the latter measure equal to the former; so that lines at right angles to each other, enclosing the figure, will form a square.”
The Vitruvian Man is not only an embodied X; it is also a perfectly geometric way to understand ourselves. It is a key to our conception of space. The X is older than algebra or Elon; it is, per Vitruvius, a fundamentally human shape.
In turn, it’s no surprise this embodied X has become a go-to for logos. Consider Burning Man. Or Cingular Wireless. Or USA Gymnastics. Or Cigna. In all these contexts, the embodied X represents something ideal, something innately human — be it community, connectivity, athleticism, or health.
Elon Musk’s company joins this long chain of X’s, from Vitruvius to Descartes to Cigna. Another entry in a long history of our obsession with this letter, this shape, this embodied symbol.