Blindness that becomes sight is the awakening of inner perception in a person who once moved through life seeing nothing of their own depths, and the doubt raised against it is the ordinary reasoning mind refusing to credit an inward change it did not itself produce. The demand to call the parents is that same skeptical faculty insisting on tracing the awakening back to its origin, needing witnesses to the source before it will accept that the eyes of understanding have truly opened.
The whole drama is interior: one part of the person has begun to see, and another part cross-examines the change, unwilling to believe that real vision has come until it can account for where it started. The awakening is genuine even while the doubting mind still searches for proof.
The blind man given sight: the faculty of inner perception waking in one who lived unaware of their own depths
The parents: the origin of the awakening, the source the doubting mind demands to summon before it will believe