Why is 'x' the unknown? | Terry Moore

Translator: Timothy Covell Reviewer: Jenny Zurawell

譯者: Chuan-Chih Cheng 審譯者: Karen SONG

I have the answer to a question that we've all asked.

對於一個我們都會問的問題 我有個答案

The question is,

這個問題是

Why is it that the letter X

為什麼 X 這個字母

represents the unknown?

表示未知數？

Now I know we learned that in math class,

我們都在數學課中學過

but now it's everywhere in the culture --

但它也延伸到日常文化的各個角落

The X prize, the X-Files,

X Prize 全球創新獎、X 檔案

Project X, TEDx.

X 計畫、TEDx

Where'd that come from?

X 到底從何而來？

About six years ago

大約在六年前

I decided that I would learn Arabic,

我決定學阿拉伯文

which turns out to be a supremely logical language.

一種具高度邏輯性的語言

To write a word or a phrase

利用阿拉伯文書寫一個字或一個單詞

or a sentence in Arabic

或一個句子

is like crafting an equation,

就像在刻劃一個方程式

because every part is extremely precise

因為每個部分都極度準確

and carries a lot of information.

而且蘊含大量資訊

That's one of the reasons

這是其中一個原因

so much of what we've come to think of

為什麼我們現在稱之為

as Western science and mathematics and engineering

西方科學、數學和工程學

was really worked out in the first few centuries of the Common Era

皆是在西元初期幾個世紀

by the Persians and the Arabs and the Turks.

由波斯人、阿拉伯人 和土耳其人所發展出來的

This includes the little system in Arabic

其中包括阿拉伯文稱作

called al-jebra.

"al-jebra" 的小系統

And al-jebr roughly translates to

"al-jebr" 大概的意思是

"the system for reconciling disparate parts."

一套調和不同部分的系統

Al-jebr finally came into English as algebra.

"Al-jebr" 發展成英文的代數

One example among many.

這是眾多例子中的其中一個

The Arabic texts containing this mathematical wisdom

包含了數學智慧的阿拉伯文字

finally made their way to Europe --

後來傳播到歐洲

which is to say Spain --

準確說是西班牙

in the 11th and 12th centuries.

時期約為 11 至 12 世紀

And when they arrived

對它們的到來

there was tremendous interest

人們有著濃厚的興趣

in translating this wisdom

要把這種智慧

into a European language.

翻譯成歐洲的語言

But there were problems.

但產生了一些問題

One problem

其中有一個是

is there are some sounds in Arabic

有些阿拉伯語的發音

that just don't make it through a European voice box

歐洲人是發不出來的

without lots of practice.

不經過大量練習的話

Trust me on that one.

這點你們要相信我

Also, those very sounds

此外，這些特別的發音

tend not to be represented

在歐洲語言中

by the characters that are available in European languages.

也找不到字母來代表它們

Here's one of the culprits.

這裡有一個例子

This is the letter sheen,

這個字念作 "sheen"

and it makes the sound we think of as SH -- "sh."

和英文中的 "sh" 發一樣的音

It's also the very first letter

也是 "shayun" 這個字的開頭

of the word shayun,

which means "something"

代表「某些東西」

just like the the English word "something" --

而就像英文中「某些東西」的字義

some undefined, unknown thing.

某些未定義、未知的事物

Now in Arabic,

在阿拉伯語中

we can make this definite

我們可以在這個字前面

by adding the definite article "al."

加上 "al" 這個定冠詞

So this is al-shayun --

就變成了 "al-shayun"

the unknown thing.

「未知的事物」

And this is a word that appears throughout early mathematics,

而這個單字在早期的數學中出現

such as this 10th-century derivation of roots.

例如這道十世紀的推導證明題

The problem for the Medieval Spanish scholars

對於中世紀那些

who were tasked with translating this material

負責翻譯這些教材的西班牙學者而言

is that the letter sheen and the word shayun

問題是字母 "sheen" 和單字 "shayun"

can't be rendered into Spanish

無法用西班牙語表達

because Spanish doesn't have that SH,

因為西班牙語裡沒有 "SH" 的發音

that "sh" sound.

So by convention,

所以依照常規

they created a rule in which

他們創了一個規則

they borrowed the CK sound, "ck" sound,

從古希臘語中借了 "ck" 這個音

from the classical Greek

in the form of the letter Kai.

用 "X" (Kai) 這個字母表達出來

Later when this material was translated

而後當這些教材被翻譯成

into a common European language,

通用的歐洲語言

which is to say Latin,

也就是拉丁文

they simply replaced the Greek Kai

他們把希臘語中的 "X" (Kai)

with the Latin X.

替換成拉丁文中的 "X"

And once that happened,

而當這件事發生

once this material was in Latin,

當教材已被翻譯成拉丁文

it formed the basis for mathematics textbooks

就成了其後 600 年的 數學課本的基礎

for almost 600 years.

But now we have the answer to our question.

現在來到了問題的答案

Why is it that X is the unknown?

為什麼 X 代表未知?

X is the unknown

這是因為

because you can't say "sh" in Spanish.

你沒辦法在西班牙語中發 "sh" 的音

(Laughter)

（笑聲）

And I thought that was worth sharing.

而我覺得這值得分享給大家

(Applause)

（全場鼓掌）