It was an idea that had arrived somewhat by chance.
这几乎是图灵偶然得到的想法。
On the American side, they had thought of storing instructions internally because it was the only way of supplying instructions quickly enough.
对美国方面来说，他们之所以能想到内部存储指令，是因为这是快速供应指令的唯一方法。
On the Turing side, he had simply taken over the single tape of the old Universal Turing Machine.
而对于图灵来说，这只不过是很自然地延续了通用图灵机的单一纸带。
But neither of these reasons for adopting stored instructions said anything about the possibility of interfering with the instructions in the course of a computation.
但是，这两种不同的理由，都没有涉及一种新的可能，也就是指令可以在计算过程中进行改变。
On the American side, it was not pointed out as a feature of the new design until 1947.
美国方面直到1947年，才考虑到这个新特性。
Equally, the Universal Turing Machine, in its paper operation, was not designed to change the 'description number' that it worked upon.
同样，通用图灵机在纸上操作时，也不能改变正在执行的描述数，
It was designed to read, decode, and execute the instruction table stored upon its tape.
它只能取出、识别和执行存储在纸带上的指令，
It would never change these instructions.
这样的设计永远不能使指令发生改变。
The Universal Turing Machine of 1936 was like the Babbage machine in the way that it would operate with a fixed stock of instructions.
1936年的通用图灵机，只能操作固定存储的指令，这点与巴贝奇机是一样的。
(It differed in that that stock was stored in exactly the same medium as the working and the input and output.)
（不同的是，图灵机的指令存储、工作空间、输入和输出，都在同一介质上。）
And so Alan Turing's own 'universality' argument showed that a Babbage-like machine was enough.
根据图灵关于通用性的观点，一个类似巴贝奇机的机器就已经足够了，
In principle there was nothing that could be achieved through modifying the instructions in the course of an operation that could not be achieved by a universal machine without this facility.
在运行过程中改变自己的指令，是个多余的特性。
The faculty of program modification could only economise on instructions, and would not enlarge upon the theoretical scope of operations.
这种特性只是能够节省指令，无法带来什么新的功能。
But that economy could, as Alan said, be 'Very powerful'.
不过，正如图灵所说，经济性也是"非常重要"的。