If the states of a Turing machine could be compared with 'states of mind', then its physical embodiment could be compared with a brain.
图灵机的状态，可以看作是思维的状态，那么它的物理载体，就可以看作是大脑了。
One important aspect of this comparison, important to anyone who was concerned with the mystery of mind, the apparent paradox of free will and determinism, was that the Turing machine model was one independent of physics.
这个类比中有一个关键之处，对所有关心思维奥秘的人来说都非常重要，那就是图灵机模型是不依赖物理实体的。
The argument from Laplacian physical determinism could be shrugged aside with the observation that no such prediction could ever be performed in practice.
拉普拉斯式的物理决定论，在现实中是无法实现的，因此这可能会成为一个反对它的理由。
This rebuttal could not be applied to a Turing machine, in which everything that happened could be described in terms of a finite set of symbols, and worked out with complete precision in terms of discrete states.
但这种理由，对图灵机是不成立的，在图灵机模型中，一切都可以用有限的符号集来描述，而且以离散的状态来精确地运行。
Later he would articulate this himself:
艾伦自己表述说：
The prediction which we are considering is however rather nearer to practicability than that considered by Laplace.
我们的模型比拉普拉斯的更具有现实性。
The system of the 'universe as a whole' is such that quite small errors in the initial conditions can have an overwhelming effect at a later time.
他所考虑的宇宙整体，是这样的一个系统，初始状态的微小偏差，会在后面产生巨大的影响。
The displacement of a single electron by a billionth of a centimetre at one moment might make the difference between a man being killed by an avalanche a year later, or escaping.
某时刻的一个电子偏移10纳米，就能决定某个人在一年后死于雪崩。
It is an essential property of the mechanical systems which we have called 'discrete state machines' that this phenomenon does not occur.
而机械系统的基本性质，就是不会发生这种情况，我们称之为离散状态机。