The Virtue Signaling Version of 'X' the Unknown

The letter “X” represents the mysterious, the unknown, the forbidden and foreboding, x- rated, x-rays. x-factor. In mathematics it represents an unknown quantity or a variable. Why is this? You may have heard of a current trendy theory with the proper air of “woke”. Apparently “al-shay-un” is an Arabic word meaning an unknown thing. And used as such to mean unknown quantity in Arabic writings on algebra. But when Spanish scholars sought to translate these writings, turns out Spanish did not have an SH sound. So Spanish scholars used the closest sound they knew of, the Greek letter Chi, which resembles the Latin letter X. Bingo, there we have it! Although it does not seem to be clear why in translation the sound of the original word is relevant.

Virtue signaling theory

There are a couple of problems with this fine virtue signaling theory. For one thing it has not a speck of evidence in support. This has not stopped its spread in academia, even among mathematicians who should know better. Of course academia has largely dispensed with the patriarchal need for evidence to support what is obviously good think. And “X” does not perform a unique function. Often in math we have more than one unknown quantity or variable, we customarily represent them with a “Y” and a “Z”. In correlation/regression we have a X and a Y variable. If we need a third variable it will be symbolized by Z. In two dimensional coordinates there are X and Y axes, and in three dimensional coordinates we have X. Y and Z axes. X, Y and Z, they seem to go together? Like at the end of the alphabet? “X” may represent the mysterious and unknown, but there is nothing mysterious or unknown about how it came to be. And nothing about it is from the exotic “Arabian Nights”. Rather the source was an arbitrary decision made by its originator, René Descartes, (1596-1650), mathematician, philosopher and dead white toxic male, to use of the last three letters of the alphabet to represent unknown quantities in his book “ La Géométrie.” La Géométrie came out in 1637 and was groundbreaking in that it combined algebra and geometry and invented Cartesian coordinates, with the familiar X and Y axes, a necessary precursor to calculus which was to be invented by Isaac Newton and Gottfried Leibniz, independently, circa 1670. In this book, Descartes was to use the last three letters of the alphabet, X, Y and Z, to represent the unknown quantities, using the first three letters of the alphabet, when he needed to represent constants. It was just as simple as that. “ La Géométrie.” was also groundbreaking in that it was written in French. Scholarly works, including most of Descartes own philosophical writings, were still being written in Latin at the time. But at some point Descartes made a conscious decision to write in French.

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By the way the Muslims did not invent algebra, zero or “Arabic” numerals. The ancient Babylonians had sophisticated mathematics from around 2000 BC, and were familiar with with algebra and the idea of zero by then. With the religiously motivated closing of the Athenian Academy in 529 AD, by Justinian the Great, Eastern Roman emperor, mathematics was virtually ended in the west. So the word “algebra” does in fact come from Arabic, as algebra had to be reintroduced into the west through Muslim sources, But the “al-shay-un“ into Chi theory of why X represents the unknown in mathematics has a bright future, although English does have the “SH” sound and a popular obscenity using the sound describes the theory. But as the line from “The Man Who Shot Liberty Valance.” goes;

“This is the West, sir. When the legend becomes fact, print the legend.”

Of course the line used the word “West” in a different sense than meaning North America and Europe but it is very appropriate considering what the post modern West looks like today. It was a great movie, I wonder if it has been banned yet.