In practice, predictions could not be performed except in the most simple of cases, but in principle there was no dividing line between these and systems of any complexity.

但在实践中，除了一些极简单的系统之外，这种预测是无法实现的。而且在理论上，这些简单系统，和复杂系统之间，也并没有什么本质上的区别。

It was also true that some sciences, thermodynamics and chemistry for instance, considered only averaged-out quantities, and in those theories information could appear and disappear.

还有一个事实是，在某些学科中，比如热力学和化学，通常只考虑总体平均情形，在这些理论中，信息可以出现，也可以消失。

When the sugar has dissolved in the tea, there remains no evidence, on the level of averages, that it was ever in the form of a cube.

当一块糖在茶中融化了，总体平均来看它还是一块糖，但它本来携带的信息就消失了。

But in principle, at a sufficiently detailed level of description, the evidence would remain in the motion of the atoms.

但是，假如能够充分描述其细节，那么那些丢失的信息，仍然保留在原子的运动中。

That was the view as summed up by Laplace13 in 1795:

这就是拉普拉斯在1795年总结的观点：

Given for one instant an intelligence which could comprehend all the forces by which nature is animated and the respective situations of the beings who compose it – an intelligence sufficiently vast to submit these data to analysis – it would embrace in the same formula the movements of the greatest bodies and those of the lightest atom;

假如有一位强大的智者，他能综合所有驱动自然的力，以及施力物体的所有情况，并且能够分析所有这些数据，那么对他来说，就没有什么是不确定的。

for it, nothing would be uncertain and the future, as the past, would be present to its eyes.

未来就会如同历史一样，展现在他的眼前。

From this point of view, whatever might be said about the world on other levels of description (whether of chemistry, or biology, or psychology, or anything else), nevertheless, there was one level of description, that of microscopic physical detail, in which every event was completely determined by the past.

这个观点意味着，对于我们用其它方式（比如化学、生物学或其它方式）描述的任何事物，都还存在着一个包含所有物理细节的描述，在这种描述下，一个事情完全取决于过去。