托福阅读素材（二）

9:36

　　Now here's one other thing you can do with the computer model. So imagine a monkey sitting at a keyboard. I think you might get a random jumble of letters that looks like this. Such a random jumble of letters is said to have a very high entropy. This is a physics and information theory term. But just imagine it's a really random jumble of letters. How many of you have ever spilled coffee on a keyboard?You might have encountered the stuck-key problem -- so basically the same symbol being repeated over and over again. This kind of a sequence is said to have a very low entropy because there's no variation at all. Language, on the other hand, has an intermediate level of entropy; it's neither too rigid,nor is it too random. What about the Indus script? Here's a graph that plots the entropies of a whole bunch of sequences. At the very top you find the uniformly random sequence, which is a random jumble of letters -- and interestingly, we also find the DNA sequence from the human genome and instrumental music. And both of these are very, very flexible, which is why you find them in the very high range. At the lower end of the scale, you find a rigid sequence, a sequence of all A's, and you also find a computer program, in this case in the language Fortran, which obeys really strict rules. Linguistic scripts occupy the middle range.

　　10:49

　　Now what about the Indus script? We found that the Indus script actually falls within the range of the linguistic scripts. When this result was first published, it was highly controversial. There were people who raised a hue and cry, and these people were the ones who believed that the Indus script does not represent language. I even started to get some hate mail. My students said that I should really seriously consider getting some protection. Who'd have thought that deciphering could be a dangerous profession? What does this result really show? It shows that the Indus script shares an important property of language. So, as the old saying goes, if it looks like a linguistic script and it acts like a linguistic script, then perhaps we may have a linguistic script on our hands. What other evidence is there that the script could actually encode language?

　　11:38

　　Well linguistic scripts can actually encode multiple languages. So for example, here's the same sentence written in English and the same sentence written in Dutch using the same letters of the alphabet. If you don't know Dutch and you only know English and I give you some words in Dutch,you'll tell me that these words contain some very unusual patterns. Some things are not right, and you'll say these words are probably not English words. The same thing happens in the case of the Indus script. The computer found several texts -- two of them are shown here -- that have very unusual patterns. So for example the first text: there's a doubling of this jar-shaped sign. This sign is the most frequently-occurring sign in the Indus script, and it's only in this text that it occurs as a doubling pair.