雙語暢銷書《艾倫圖靈傳》第3章:思考什麼是思考(77)
However, the typewriter had a further feature which was essential to its function. Its typing point could move, relative to the page.
Its typing action would be independent of the position of this point on the page.
而它要打什麼字，與它的打印頭在什麼位置是無關的。Alan incorporated this idea too into his picture of the more general machine.
艾倫把這個想法，也推廣到他設想的機器中。
It was to have internal 'configurations', and a variable position on a printing line.
這個機器有內部的狀態，還有一個可以移動的打印頭，The action of the machine would not depend upon its position.
但它的動作與打印頭的位置無關。Neglecting details as to margins, line control, and so forth, these ideas would suffice to give a complete description of the nature of a typewriter.
如果忽略頁邊距和換行等細節，上面這些想法，就描述了打字機的本質。An exact account of the configurations and positions allowed, and of how the character keys determined the symbols printed, the shift key the change of configuration from 'lower' to 'upper', and the space bar and backspace the printing position, would bring out the features most relevant to its function.
狀態和允許的位置，鍵盤如何確定打印的字符，換檔鍵切換大小寫，還有空格和退格。If an engineer took this account, and created a physical machine which met its specifications, the result would be a typewriter, regardless of its colour, weight, or other attributes.
一個工程師只要知道這些，並且造出一臺相應的機器，無論是什麼顏色、什麼重量，它就是一臺打字機。But a typewriter was too limited to serve as a model.
但是，用打字機作爲模型，太有侷限性了。It dealt with symbols, but it could only write them, and it required a human operator to choose the symbols and changes of configuration and position, one at a time.
雖然它能處理符號，但它只是把符號印出來，而且它還需要人類操作者來逐個選擇符號，改變大小寫和位置。What, Alan Turing asked, would be the most general kind of machine that dealt with symbols?
艾倫·圖靈便問，那麼什麼樣的符號機器纔是普適的呢？To be a 'machine' it would have to retain the typewriter's quality of having a finite number of configurations, and an exactly determined behaviour in each.
作爲機器，它要保留打字機的有限狀態和確定行爲。But it would have to be capable of much more.
但只有這些是不夠的，它還要有些別的。And so he imagined machines which were, in effect, super-typewriters.
艾倫設想的機器，相當於一臺超級打字機。To simplify the description he imagined his machines working with just one line of writing. This was only a technicality, which allowed margins and line control to be forgotten.
爲了簡化，他忽略了頁邊距和換行這樣的技術問題，設想這臺機器只在一行上工作。But it was important that the supply of paper was to be assumed unlimited.
但重要的是，他設想紙帶的長度是無限的。In his picture, the typing point of his super-typewriter could progress indefinitely to left or right.
在他的描述中，他的超級打字機，可以無限地在紙帶上向左或向右移動。For the sake of definiteness, he imagined the paper as being in the form of a tape, marked off into unit squares, such that just one symbol could be written on any one square.
爲了清晰，他設想紙帶劃分成方格子，每個方格只能寫一個符號。Thus his machines were to be finitely defined, but they would be allowed an unlimited amount of space on which to work.
這樣，他的機器是有限定義的，但卻擁有無限的空間來工作。
