"Every perception is to some degree an act of creation, and every act of memory is to some degree an act of imagination."
-- Gerald Edelman, Second Nature: Brain Science and Human Knowledge
4 How important is memory, anyway？6 How important is memory, anyway？How important is memory, anyway？How can we develop transformative tools for thought？2020-10-18Journal
Another common argument against spaced repetition systems is that it's better to rely on natural repetition. For instance, if you're learning a programming language, the argument goes, you shouldn't memorize every detail of that language. Instead, as you use the language in real projects you'll naturally repeatedly use, and eventually commit to memory, those parts of the language most important to learn.
There are important partial truths in this. It is good to use what you're learning as part of your creative projects. Indeed, an ideal memory system might help that happen, prompting you as you work, rather than in an artificial card-based environment. Furthermore, a common failure mode with memory systems is that people attempt to memorize things they're unlikely to ever have any use for. For instance, it's no good (but surprisingly common) for someone to memorize lots of details of a programming language they plan to use for just one small project. Or to memorize details “just in case” they ever need them. These patterns are mistakes.