我在看高山写的“量子”历史之旅
其中讲到爱因斯坦的话

“许多物理学家断言──而且有许多有利于他们的有力论据──在这些事实面前，
不仅微分定律，而且因果律本身（直到现在，这是一切自然科学的终极的基本假设）
也已经破产了……德布罗意─薛定谔方法在某种意义上是具有场论特征的，它确实
推算出只存在分立的状态，这同经验事实取得了惊人的一致……但是它必须放弃质
点的定位和严格的因果律……谁敢在今天断定这样的问题：因果律和微分定律这两
条牛顿自然观的终极前提是不是一定要放弃呢？
　　──爱因斯坦，1927年3月20日”

这里，微分定律指的是什么？

所谓“微分定律”就是指客观物体的状态可以在一个连续的状态区间取任意一个状态。而量子力学里，很多系统的状态是分立的，它的合法状态集合是离散（但是，未必是有限的）的。所以说微分定律不再成立。

谢谢，我也猜想是这样，但不敢肯定

"Differential law" is a very weird statement.

If it refers to whether dynamical variable could only take discrete values, then it almost has nothing to do with a system is quantized or not. There are plenty of classical system, such as a standing wave, also have this property.

If it refers to whether a system's evolution are described by a set of continuous
differential equations, this is case for both classical and quantum systems.

In the early days of quantum mechanics, everybody, including people like Einstein and Bohr, were very confused (as they should). They made a lot of statements which does not quite make sense given our current understanding of QM.

It is a bravery for them to struggle to understand a bran new dynamics. It is stupid for people to still hang on to some of their statements as if it is the final word.

很多时候，一句话是谁说的很重要：-)