I think the better systems of literate programming allow you to change code in either place. I.e., you can edit the "literate code", which is "tangled" to create a directly compilable codebase. Or you can edit the "tangled" codebase, and have changes there be "untangled" to the literate form of the project.

I'm not sure whether this is an issue merely for the new versus the experienced programmer. It is an issue I see as even more important to debugging, where all the debugging tools a programmer uses are geared towards working with the compilable codebase, not the literate one. To make things work smoothly you need to be able to edit the compilable codebase and have changes be reflected in its untangled (i.e., literate) form.