You know, if you want to measure the potential energy of something in a gravitational field, you have to define the zero somewhere, right, because it's arbitrary. You can set it anywhere you want. It's the same with enthalpy.

你知道，如果你想测量重力场,中某种东西的势能，你需要，在某处定义一个零点，对吧？,因为势能的值是任意的,你可以把它设定在。

麻省理工公开课 - 热力学与动力学课程节选

There's nothing profound about this, other than the understanding that the details of how you set these things up can matter a lot.

只是说我们要理解，一开始设定时候的值,会对结果有很大影响。

麻省理工公开课 - 计算机科学及编程导论课程节选