Blake isn't endorsing foolishness—he's describing how wisdom often arrives through stubborn repetition rather than sudden enlightenment. Most people expect insight to dawn like morning light, but Blake suggests something stranger: that continuing down a wrong path long enough teaches you its geometry in ways caution never could. A musician who plays the same difficult passage hundreds of times, failing each time, eventually understands it viscerally—not because she stopped being a fool, but because her foolish persistence became a kind of unwilling education. The paradox he's offering is that the path to wisdom sometimes requires you to be courageously, almost recklessly, committed to your own mistakes.