[sradman]

I consider Spaced Repetition a mental model of how we learn and retain knowledge. I think your objection is with flash card systems and I don’t disagree with your assessment.

I think of Spaced Repetition more generally. A paper based Zettelkasten system can be enhanced with a paper based review scheduling system; say 43 folders as described by David Allen in Getting Things Done with a simple SuperMemo algorithm for interval spacing.

When we gain good recall of Zettelkasten structure/content I suspect that we inadvertently mimic Spaced Repetition. I can be convinced otherwise.