Memorization comes from understanding, not the other way around. If you memorize the alphabet - congrats you can sing a song. If you understand the alphabet - you can write a book, singing the song is a side effect.
A better example to express your point would be multiplication tables. Why memorize a list of multiplicands and their products rather than learn what multiplication means so that you can generate them on the fly and only memorize as a by-product of common use?
In order to learn something usefully, and be able to retain that knowledge for years to come, you must have a fundamental understanding of the underlying principles.