[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.61,0:00:04.21,Default,,0000,0000,0000,,I have the answer to a question that we've all asked.
Dialogue: 0,0:00:04.21,0:00:05.33,Default,,0000,0000,0000,,The question is,
Dialogue: 0,0:00:05.33,0:00:07.61,Default,,0000,0000,0000,,Why is it that the letter X
Dialogue: 0,0:00:07.61,0:00:09.61,Default,,0000,0000,0000,,represents the unknown?
Dialogue: 0,0:00:09.61,0:00:12.58,Default,,0000,0000,0000,,Now I know we learned that in math class,
Dialogue: 0,0:00:12.58,0:00:14.33,Default,,0000,0000,0000,,but now it's everywhere in the culture --
Dialogue: 0,0:00:14.33,0:00:17.13,Default,,0000,0000,0000,,The X prize, the X-Files,
Dialogue: 0,0:00:17.13,0:00:21.05,Default,,0000,0000,0000,,Project X, TEDx.
Dialogue: 0,0:00:21.05,0:00:23.05,Default,,0000,0000,0000,,Where'd that come from?
Dialogue: 0,0:00:23.05,0:00:24.27,Default,,0000,0000,0000,,About six years ago
Dialogue: 0,0:00:24.27,0:00:26.98,Default,,0000,0000,0000,,I decided that I would learn Arabic,
Dialogue: 0,0:00:26.98,0:00:30.93,Default,,0000,0000,0000,,which turns out to be a supremely logical language.
Dialogue: 0,0:00:30.93,0:00:33.25,Default,,0000,0000,0000,,To write a word or a phrase
Dialogue: 0,0:00:33.25,0:00:34.93,Default,,0000,0000,0000,,or a sentence in Arabic
Dialogue: 0,0:00:34.93,0:00:37.16,Default,,0000,0000,0000,,is like crafting an equation,
Dialogue: 0,0:00:37.16,0:00:39.53,Default,,0000,0000,0000,,because every part is extremely precise
Dialogue: 0,0:00:39.53,0:00:42.38,Default,,0000,0000,0000,,and carries a lot of information.
Dialogue: 0,0:00:42.38,0:00:43.73,Default,,0000,0000,0000,,That's one of the reasons
Dialogue: 0,0:00:43.73,0:00:45.25,Default,,0000,0000,0000,,so much of what we've come to think of
Dialogue: 0,0:00:45.25,0:00:49.07,Default,,0000,0000,0000,,as Western science and mathematics and engineering
Dialogue: 0,0:00:49.07,0:00:52.39,Default,,0000,0000,0000,,was really worked out in the first few centuries of the Common Era
Dialogue: 0,0:00:52.39,0:00:55.70,Default,,0000,0000,0000,,by the Persians and the Arabs and the Turks.
Dialogue: 0,0:00:55.70,0:00:58.02,Default,,0000,0000,0000,,This includes the little system in Arabic
Dialogue: 0,0:00:58.02,0:00:59.74,Default,,0000,0000,0000,,called al-jebra.
Dialogue: 0,0:00:59.74,0:01:02.91,Default,,0000,0000,0000,,And al-jebr roughly translates to
Dialogue: 0,0:01:02.91,0:01:06.60,Default,,0000,0000,0000,,"the system for reconciling disparate parts."
Dialogue: 0,0:01:06.60,0:01:10.66,Default,,0000,0000,0000,,Al-jebr finally came into English as algebra.
Dialogue: 0,0:01:10.66,0:01:12.82,Default,,0000,0000,0000,,One example among many.
Dialogue: 0,0:01:12.82,0:01:16.79,Default,,0000,0000,0000,,The Arabic texts containing this mathematical wisdom
Dialogue: 0,0:01:16.79,0:01:18.57,Default,,0000,0000,0000,,finally made their way to Europe --
Dialogue: 0,0:01:18.57,0:01:19.86,Default,,0000,0000,0000,,which is to say Spain --
Dialogue: 0,0:01:19.86,0:01:22.32,Default,,0000,0000,0000,,in the 11th and 12th centuries.
Dialogue: 0,0:01:22.32,0:01:23.47,Default,,0000,0000,0000,,And when they arrived
Dialogue: 0,0:01:23.47,0:01:25.36,Default,,0000,0000,0000,,there was tremendous interest
Dialogue: 0,0:01:25.36,0:01:27.09,Default,,0000,0000,0000,,in translating this wisdom
Dialogue: 0,0:01:27.09,0:01:28.74,Default,,0000,0000,0000,,into a European language.
Dialogue: 0,0:01:28.74,0:01:30.76,Default,,0000,0000,0000,,But there were problems.
Dialogue: 0,0:01:30.76,0:01:32.47,Default,,0000,0000,0000,,One problem
Dialogue: 0,0:01:32.47,0:01:35.11,Default,,0000,0000,0000,,is there are some sounds in Arabic
Dialogue: 0,0:01:35.11,0:01:38.10,Default,,0000,0000,0000,,that just don't make it through a European voice box
Dialogue: 0,0:01:38.10,0:01:40.37,Default,,0000,0000,0000,,without lots of practice.
Dialogue: 0,0:01:40.37,0:01:42.11,Default,,0000,0000,0000,,Trust me on that one.
Dialogue: 0,0:01:42.11,0:01:44.32,Default,,0000,0000,0000,,Also, those very sounds
Dialogue: 0,0:01:44.32,0:01:46.24,Default,,0000,0000,0000,,tend not to be represented
Dialogue: 0,0:01:46.24,0:01:49.82,Default,,0000,0000,0000,,by the characters that are available in European languages.
Dialogue: 0,0:01:49.82,0:01:51.64,Default,,0000,0000,0000,,Here's one of the culprits.
Dialogue: 0,0:01:51.64,0:01:53.52,Default,,0000,0000,0000,,This is the letter SHeen,
Dialogue: 0,0:01:53.52,0:01:57.12,Default,,0000,0000,0000,,and it makes the sound we think of as SH -- "sh."
Dialogue: 0,0:01:57.12,0:01:59.72,Default,,0000,0000,0000,,It's also the very first letter
Dialogue: 0,0:01:59.72,0:02:02.16,Default,,0000,0000,0000,,of the word shalan,
Dialogue: 0,0:02:02.16,0:02:03.95,Default,,0000,0000,0000,,which means "something"
Dialogue: 0,0:02:03.95,0:02:05.80,Default,,0000,0000,0000,,just like the the English word "something" --
Dialogue: 0,0:02:05.80,0:02:09.08,Default,,0000,0000,0000,,some undefined, unknown thing.
Dialogue: 0,0:02:09.08,0:02:10.25,Default,,0000,0000,0000,,Now in Arabic,
Dialogue: 0,0:02:10.25,0:02:11.45,Default,,0000,0000,0000,,we can make this definite
Dialogue: 0,0:02:11.45,0:02:13.60,Default,,0000,0000,0000,,by adding the definite article "al."
Dialogue: 0,0:02:13.60,0:02:16.20,Default,,0000,0000,0000,,So this is al-shalan --
Dialogue: 0,0:02:16.20,0:02:17.85,Default,,0000,0000,0000,,the unknown thing.
Dialogue: 0,0:02:17.85,0:02:21.15,Default,,0000,0000,0000,,And this is a word that appears throughout early mathematics,
Dialogue: 0,0:02:21.15,0:02:28.35,Default,,0000,0000,0000,,such as this 10th century derivation of proofs.
Dialogue: 0,0:02:28.35,0:02:30.86,Default,,0000,0000,0000,,The problem for the Medieval Spanish scholars
Dialogue: 0,0:02:30.86,0:02:33.43,Default,,0000,0000,0000,,who were tasked with translating this material
Dialogue: 0,0:02:33.43,0:02:37.91,Default,,0000,0000,0000,,is that the letter SHeen and the word shalan
Dialogue: 0,0:02:37.91,0:02:39.86,Default,,0000,0000,0000,,can't be rendered into Spanish
Dialogue: 0,0:02:39.86,0:02:42.45,Default,,0000,0000,0000,,because Spanish doesn't have that SH,
Dialogue: 0,0:02:42.45,0:02:43.75,Default,,0000,0000,0000,,that "sh" sound.
Dialogue: 0,0:02:43.75,0:02:45.33,Default,,0000,0000,0000,,So by convention,
Dialogue: 0,0:02:45.33,0:02:46.99,Default,,0000,0000,0000,,they created a rule in which
Dialogue: 0,0:02:46.99,0:02:51.21,Default,,0000,0000,0000,,they borrowed the CK sound, "ck" sound,
Dialogue: 0,0:02:51.21,0:02:52.96,Default,,0000,0000,0000,,from the classical Greek
Dialogue: 0,0:02:52.96,0:02:55.64,Default,,0000,0000,0000,,in the form of the letter Kai.
Dialogue: 0,0:02:55.64,0:02:58.36,Default,,0000,0000,0000,,Later when this material was translated
Dialogue: 0,0:02:58.36,0:03:00.71,Default,,0000,0000,0000,,into a common European language,
Dialogue: 0,0:03:00.71,0:03:02.76,Default,,0000,0000,0000,,which is to say Latin,
Dialogue: 0,0:03:02.76,0:03:04.79,Default,,0000,0000,0000,,they simply replaced the Greek Kai
Dialogue: 0,0:03:04.79,0:03:07.14,Default,,0000,0000,0000,,with the Latin X.
Dialogue: 0,0:03:07.14,0:03:08.41,Default,,0000,0000,0000,,And once that happened,
Dialogue: 0,0:03:08.41,0:03:10.88,Default,,0000,0000,0000,,once this material was in Latin,
Dialogue: 0,0:03:10.88,0:03:14.46,Default,,0000,0000,0000,,it formed the basis for mathematics textbooks
Dialogue: 0,0:03:14.46,0:03:16.54,Default,,0000,0000,0000,,for almost 600 years.
Dialogue: 0,0:03:16.54,0:03:18.56,Default,,0000,0000,0000,,But now we have the answer to our question.
Dialogue: 0,0:03:18.56,0:03:21.34,Default,,0000,0000,0000,,Why is it that X is the unknown?
Dialogue: 0,0:03:21.34,0:03:23.16,Default,,0000,0000,0000,,X is the unknown
Dialogue: 0,0:03:23.16,0:03:26.94,Default,,0000,0000,0000,,because you can't say "sh" in Spanish.
Dialogue: 0,0:03:26.94,0:03:29.33,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:03:29.33,0:03:31.65,Default,,0000,0000,0000,,And I thought that was worth sharing.
Dialogue: 0,0:03:31.65,0:03:34.76,Default,,0000,0000,0000,,(Applause)