Why is 'x' the unknown? | Terry Moore

Translator: Timothy Covell Reviewer: Jenny Zurawell

翻译人员: Sicheng Pan 校对人员: Ricki Xie

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

我来回答一个大家都问过的问题。

The question is,

这个问题是，

Why is it that the letter X

为什么字母“X”

represents the unknown?

代表着未知数？

Now I know we learned that in math class,

我知道这在数学课学过，

but now it's everywhere in the culture --

现在它在日常文化里也随处可见

The X prize, the X-Files,

X奖，X档案，

Project X, TEDx.

Projet X，TEDx。

Where'd that come from?

这些都是从哪里来的？

About six years ago

大约六年前，

I decided that I would learn Arabic,

我决定学习阿拉伯语，

which turns out to be a supremely logical language.

这是一个非常有逻辑性的语言。

To write a word or a phrase

每用阿拉伯语写一个词

or a sentence in Arabic

或一个句子，

is like crafting an equation,

就如编解一道方程，

because every part is extremely precise

因为它的每一部分都非常精确

and carries a lot of information.

还伴随着很多信息。

That's one of the reasons

这是为什么

so much of what we've come to think of

大多数的我们认为

as Western science and mathematics and engineering

西方的科学、数学和技术

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

都是在公元最初的世纪

by the Persians and the Arabs and the Turks.

被波斯人、阿拉伯人和土耳其人所发明的原因之一。

This includes the little system in Arabic

这其中包括一个在阿拉伯语中称为

called al-jebra.

“al-jabr”的系统。

And al-jebr roughly translates to

而“al-jabr”大致的意思是

"the system for reconciling disparate parts."

“一套将无关‘代’化成相关的体系”。

Al-jebr finally came into English as algebra.

后来“Al-jabr”变成了英文中的代数。

One example among many.

这是众多（关于阿拉伯语的）例子之一。

The Arabic texts containing this mathematical wisdom

最终，带有数学智慧的阿拉伯文学

finally made their way to Europe --

传播到了欧洲，

which is to say Spain --

确切的来说，也就是说西班牙--

in the 11th and 12th centuries.

在11和12世纪。

And when they arrived

而它们的到来

there was tremendous interest

在当时社会，人们有着浓厚的兴趣

in translating this wisdom

想要把这个智慧

into a European language.

翻译成为欧洲的语言。

But there were problems.

但是问题也随着出现了。

One problem

其中一个问题说的是

is there are some sounds in Arabic

阿拉伯语中存在一些发音

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

是欧洲人无论如何也无法发出的

without lots of practice.

如果没有经过大量的练习。

Trust me on that one.

这点您可相信我

Also, those very sounds

此外，这些发音

tend not to be represented

往往不能被

by the characters that are available in European languages.

欧洲语言中已有的字母来表示。

Here's one of the culprits.

有这么一个例子，

This is the letter sheen,

这是字母“SHeen”，

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

它对应我们英文中SH的发音－“sh”。

It's also the very first letter

它也是

of the word shayun,

“shalan”这个词的首字母，

which means "something"

意思是 “某物”。

just like the the English word "something" --

就跟英语中的“某物 (something)”一个意思，

some undefined, unknown thing.

代表某些未定义或未知的东西。

Now in Arabic,

而在阿拉伯语中，

we can make this definite

它可以变得有意义

by adding the definite article "al."

当我们写上定冠词 “al”之后

So this is al-shayun --

这是 al-shalan,

the unknown thing.

代表着“未知的东西”。

And this is a word that appears throughout early mathematics,

而这个单词的行踪贯穿于早期数学，

such as this 10th-century derivation of roots.

比如在这个10世纪的证明题里。

The problem for the Medieval Spanish scholars

当时负责翻译这些材料的

who were tasked with translating this material

中世纪西班牙学者遇到了难题

is that the letter sheen and the word shayun

这个“SHee”字母和“shalan” 一词

can't be rendered into Spanish

无法用西班牙语表达

because Spanish doesn't have that SH,

因为西班牙语中没有“SH”的

that "sh" sound.

“sh”发音。

So by convention,

所以依照惯例，

they created a rule in which

他们创建了一个规则，

they borrowed the CK sound, "ck" sound,

他们借用“CK”的发音－“ck”，

from the classical Greek

这来自于古希腊语中的

in the form of the letter Kai.

字母“X (Kai)”。

Later when this material was translated

后来，当这篇文章被翻译成为

into a common European language,

一个欧洲的通用语言，

which is to say Latin,

也就是拉丁语，

they simply replaced the Greek Kai

他们简单的把希腊语中的“X (Kai)”

with the Latin X.

用拉丁语中的“X”代替。

And once that happened,

一旦这实现了，

once this material was in Latin,

一旦翻译成了拉丁语，

it formed the basis for mathematics textbooks

它就为数学教科书打下了基础

for almost 600 years.

从此至今已将近600年。

But now we have the answer to our question.

我们现在有了一开始问题的答案。

Why is it that X is the unknown?

为什么是“X”代表着未知数？

X is the unknown

“X”是未知数

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

因为你无法在西班牙语中发"sh"这个音。

(Laughter)

（笑）

And I thought that was worth sharing.

我认为这值得共享。

(Applause)

（掌声）