Alexandria was the chief city of Hellenistic and Roman Egypt, and the most important cultural powerhouse of the ancient Mediterranean. The quotation above comes from this History Channel clip about its famous library, or rather libraries.

亚历山大是希腊化和罗马时代埃及的主要城市，也是古地中海最重要的文化中心。以上引文来自【链接】这个历史频道，是关于它著名的图书馆的。

The narrator goes on (at the 1 min. 39 sec. mark):

旁白说道：

In the battle that followed, Caesar ordered his soldiers to burn the Egyptian fleets lying in the harbour. The fire quickly spread from the waterfront to the great library. The flames consumed a large part of the library's collection, marking the single greatest loss of knowledge in history.

“在随后的战斗中，凯撒命令他的士兵们烧毁停在港口的埃及舰队。大火迅速从码头蔓延到大图书馆。大火烧毁了图书馆的大部分藏书，造成了历史上最大的一次知识损失。

Some historians speculate that the fire set civilisation back by a thousand years. Who knows, if the great library of Alexandria hadn't burned, Columbus may not have sailed to the New World. He might have gone to the moon!

一些历史学家推测这场大火使人类文明倒退了一千年。说不定，如果亚历山大大图书馆没有被烧毁，哥伦布可能去的就不是新大陆了，他去的可能是月球！

Recently a new library was built in Alexandria, but it can never replace the ancient collection burnt in the fire. It contained rare manuscxts, the comedies of Aristotle, and more than 200 plays by Aeschylus and Euripides — classic works forever lost.

最近，亚历山大城建了一座新图书馆，但它永远无法复原在大火中烧毁的古代藏书了。里面包含了罕见的手稿、亚里士多德的喜剧，以及埃斯库罗斯和欧里庇得斯的200多部戏剧——这些经典作品都永远消失了。”

This snippet ranges from absurd to outright false. (Let's do the easy bits right away: Aristotle didn't write comedies, and Aeschylus and Euripides wrote a combined total of about 170 plays.) The only bit that has any basis in reality is the first line, about Caesar burning the Ptolemaic fleet. Everything else is untrue, without any room for doubt on the point.

这个视频片段是荒谬的、完全错误的。（我们马上进行简单的部分：亚里士多德没有写过喜剧，埃斯库罗斯和欧里庇得斯合共写了大约170部戏剧。）唯一有点依据的部分是第一行，关于凯撒火烧托勒密舰队。其他一切都不是真的，这方面没有任何怀疑的余地。

It's not like the History Channel is conveying an isolated opinion, by the way. It is really widely believed. Here's a full-length documentary that makes similar claims; the Wikipedia article on the subject refers to "the incalculable loss of ancient works"; Joel Levy's 2006 book Lost Histories calls it "the day that history lost its memory"; online forums frequently get questions about just how big a disaster it was.

顺便说一下，这个历史频道传达的并不是个孤立的看法。实际上这种看法是被广泛相信的。这是一部长篇纪录片【链接】，里边提出了类似的主张；维基百科上面关于这一主题的文章里也提到“古代作品无法估量的损失”； 乔尔·利维2006年出版的《失落的历史》一书称之为“历史失去记忆的一天”； 网上论坛经常有人问，这场灾难到底有多大。

If the loss of the library was "the single greatest loss of knowledge" in history, that would mean the books destroyed were the only existing copies of those books.

如果图书馆的损失是历史上“最大一次的知识损失”， 那意味着被毁的书是唯一现存的副本。

Suppose — heaven forfend — that the British Library burned down tomorrow, or the Library of Congress. What kind of a loss would it be? In cultural terms, and purely in monetary terms, it would be catastrophic: millions of manuscxts, autographs, and rare and unique items would be lost, and the cost of replacing the printed collection would be vast.

假设——大英图书馆或者美国国会图书馆明天被烧毁。那会是什么程度的损失呢？从文化角度来看，纯粹从货币角度来看，这将是灾难性的：无数份手稿、签名以及罕见、独特的物品将损失，更换印刷藏品的成本会很巨大。

But barely a scrap of actual knowledge would be lost. Ismail Kadare's novels would survive. The Thirty Years War would not be forgotten. Aeroplanes and computers would not become treasured relics, never to be recreated.

但几乎没有一点知识会损失。伊斯梅尔·卡达雷的小说将幸存下来。三十年战争不会被遗忘。飞机和电脑不会成为珍贵的文物，永远不会被重新创造。

This is because there are lots and lots and lots of repositories of information in the world. And exactly the same was true in Greco-Roman antiquity. There were hundreds of libraries of Greek and Latin texts dotted around the Mediterranean. Alexandria was the biggest, but it was just one fish in a sea of libraries. There were also important centres at Pergamon, Athens, Rome, Constantinople, and many important private collections. Roman aristocrats founded many libraries in the early Principate; clubs and gymnasia in Greece were also centres of learning, with their own libraries, and we have inscxtions cataloguing regular deposits of books in their collections. Caesar's fire did not stop Athenaeus and Julius Africanus from being profoundly well-read more than two centuries later, and the likes of Pliny the Elder and Pausanias did their research privately or in Athens, not in Alexandria.

这是因为世界上有很多很多的信息库。古希腊罗马时期也是如此。地中海周围散布着数百个希腊语和拉丁语图书馆。亚历山大是最大的图书馆，但它只是众多图书馆中的一个。在佩加蒙、雅典、罗马、君士坦丁堡也有重要的中心，还有许多重要的私人收藏。罗马贵族们在元首制早期建立了许多图书馆；希腊的俱乐部和健身房也是学习的中心，有自己的图书馆，我们有碑铭，对他们收藏的书籍进行定期的分类。凯撒的大火并没有阻止《Athenaeus and Julius Africanus》被广泛阅读，而老普林尼和保萨尼亚斯等人或私下研究或是在雅典研究，而不是在亚历山大进行。