For me the clearest example of the distinction of knowing something, even profoundly but not being able to practice it is writing with the “other hand” (with the left, if you’re right-handed, etc). One absolutely knows how writing works, the shape of the letters—it’s the same “brain” … but with the other hand, with the same knowledge, it doesn’t work. Same with other similar things, playing a left-handed guitar: you know the shapes of chords, the sounds of scales, you can keep time. But the pick falls to the ground, the strings buzz, and you can’t keep up.
For me the clearest example of the distinction of knowing something, even profoundly but not being able to practice it is writing with the “other hand” (with the left, if you’re right-handed, etc). One absolutely knows how writing works, the shape of the letters—it’s the same “brain” … but with the other hand, with the same knowledge, it doesn’t work. Same with other similar things, playing a left-handed guitar: you know the shapes of chords, the sounds of scales, you can keep time. But the pick falls to the ground, the strings buzz, and you can’t keep up.