How is it that someone has looked at this thread and then did nothing to find out about the knowledge that one must gain in order to understand? This is more than strange!
Returning to go deeper on this topic, I ended up here:
Foundations of the Science of Knowledge (German: Grundlage der gesammten Wissenschaftslehre) is a 1794/1795 book by the German philosopher Johann Gottlieb Fichte. Based on lectures Fichte had delivered as a Professor of Philosophy at the University of Jena, it was later reworked in various versions. The standard Wissenschaftslehre was published in 1804, but other versions appeared posthumously.[1]
I was able to find the text in pdf by internet searching for "Foundations of the Science of Knowledge pdf"
I will have to report back what I think of it; from reading several paragraphs in the introduction, I had to set it aside until earlier on a new day. A very dense thought exercise.