Terry Moore has the answer to the question that brought up to all of us. The question is;

“Why does the letter X represent something unknown thing”

Actually, we learn it in math class, but nowadays, the symbol was spread everywhere, for example – factor X, data X, project X, even TEDx. Where it‘s invented?

Around 2006, Moore decided to took an Arabic study, which proved to be a very logical language. Writing words, phrases or sentences in Arabic is like compiling an equation because every piece is very precise and carries a lot of information. That is one reason why many of us conclude that science, mathematics, and engineering in Western today really were used in the first centuries AD by the Persians, Arabs, and Turks.

For example, a small system in Arabic called al-Jabr. Grammatically, al-Jabr meaning “The system for matching different parts.” Then, Al-Jabr arrived in England as Algebra.This is one of many other examples.

The Arabic manuscript that contained various mathematic inventions reached the Europe continent, exactly Spain, in the 11th and 12th centuries. When the manuscript arrived, there was tremendous interest in translating manuscript into European languages.

The problem is, there are some sounds in Arabic that are difficult for Europeans to pronounce if they don’t practice much. And the pronunciation can not be represented or transliterated perfectly in European language letters.

One example is the letter ش, ‘šin’, in English considered as ‘sheen’ with ‘sh’ transliteration. This letter by the first letter of شيء, ‘shai‘un’ word, which means ‘something’; that is, undefined things, unknown.

In Arabic, it will becomes definitive by adding ‘al’, so it becomes اﻟﺷﻲء, ‘al-shaiun’, which is something (indicate particular thing). This word was appeared in early period of mathematics, at about 10th century.

The problem for Medieval Spanish scholars who in charge to translate these sources was the letter ش and the word ﺷﻲء cannot be converted to Spanish because it‘s didn‘t have ‘sh’ sound. Based on convention, they release a decree that they borrowed the sound ‘ck’, from the classical Greek, the letter ‘χ’ or ‘chi’.

Then, when the material translated into common European languages, Latin for example, they only replace the letters χ, ‘chi’ with Latin X. After that occurrence, and have changed to Latin, these sources had become basic mathematics textbooks for nearly 600 years.

So, we have the answer to the question. Why is ‚X‘ present „the unknown“? The answer is because Europeans cannot say ‘sh’ in Spanish. Worth to know, right?


Source: Terry Moore | TED Talk