Beginner’s Mind is very helpful in Self-inquiry. What that means is you let go of all of your concepts, all of your learning, everything you think you know – just drop it for now. Put it in your pocket, tuck it away and come at the observation and inquiry with a fresh, open, empty mind.
In this way you can, for a moment, explore your experience directly and look with a uncluttered, unbiased awareness.
All these concepts that you’ve dropped for the time being, you can pick them back up later if you find that they’re still valid or useful. But what you might find is they are neither.