Sometimes in the wee hours of the morning I like to play the piano in the dark. The problem with that, of course, is you can only play tunes you've memorized. I have one Chopin Etude I like to play but don't have entirely memorized. But almost. I've played it a million times--at least (exaggerating). I can get it started, but at some point I start thinking about what comes next, and then I lose it. But if I turn on a dim light in the kitchen that provides just a tiny glow in the living room, and then look at the music book as I play, somehow, even though I can't really see the notes in more than a vague way, I can play it. I realize the memory is in my fingers, and I just don't trust my fingers to remember, and having that crutch of a music book, even if I can't see it, helps me remember.
It's kind of like trusting your gut. Sometimes when you sit quietly and think about things without distractions, you get some very honest understandings about things. But we want to listen to our conscioius mind and ignore our gut or hunches that so often prove to be right.
Memory takes many forms, not always entirely conscious. It can be very helpful to listen to the subtle clues that come to us at such times.