by heart
Memory is fallible; a most unreliable narrator; and increasing irrelevant as we've delegated everything from grocery lists to driving routes to our smart little black mirrors. Mine is prone to corruption, and has been confused with something I watched on TV more than once. It’s one of the more compelling reasons for me to write things down.
A lot of the knowledge I gained in school was via rote learning. I can recall the lineage of Mughal emperors and the first twenty elements of the periodic table in my sleep even today. While there is no practical use of this knowledge, there are some things I learned 'by heart' pre-adulthood, that I've only now started to comprehend. For instance the abundance of Hindi song lyrics in my long-term memory, the words of which I’m only now able to ascribe meaning to.
in contrast, if I think about the things I did commit to 'understanding' years ago, I'm unable to remember those things when needed anyway. I'll be glued into a youtube video explaining tectonic plates as if I haven't already passed exams for this exact same knowledge as a teenager. I'm re-learning things, and coming to seemingly new insights, only to read my old notes and realise I had already 'figured that out' a decade ago.
maybe rote memory is a more reliable source of information than thorough comprehension and mindlessly mugging up things in childhood, wasn't such a bad idea. You do have the rest of your life to regurgitate that nonsense, and make sense of it. At least it won't be lost to the carelessness of memory.