The statement of First Law of Software Process doesn't actually mention software. And it really does apply to any process that applies knowledge. This is rather self-evident: how can you apply knowledge if you don't possess it?
The First Law (restated for knowledge): You can only have a process for applying knowledge if you already have that knowledge.
By "applying knowledge" I mean anything that uses knowledge in any way: building an artifact, writing a book, teaching someone,...
Note that, as mentioned earlier, there are two kinds of knowledge here:
The knowledge that is to be used / imparted / applied and...
The knowledge of how to use / impart /apply that knowledge.
This is simply a restatement of the necessary knowledge and process described earlier.
These are not the same. For example, in an educational environment they are the thing to be taught and the teaching method. In a book, they are the words and the activity of reading. In music they are the score and the activity of plying the instrument. They are not the same, but they are closely related.
The later statement of The Reflexive Creation of Systems and Processes further describes this duality.
Of course, the question now arises about a process for acquiring knowledge. I contend that, while there is such a "process" it is more a meta-process than a stepwise prescriptive series of actions. Equally, we can easily see a meta-process for the application of knowledge we don't have. I can descibe a meta-process for learning a foreign language: buy the appropriate language books, listen to the appropriate audio recordings, study with an appropriate teacher, etc,... What I can't do is act as that teacher unless I know the language (and can teach). All of the "appropriates" have to be resolved and, indeed, a formal syllabus for teaching the language [1].
FOOTNOTES
[1] An a lot more besides: a person to teach, a facility, a communication mechanism,...