Some of the Pharisees near him heard these things, and said to him, 'Are we also blind?' Jesus said to them, 'If you were blind, you would have no guilt; but now that you say, "We see," your guilt remains.' --John 9:40-41
The Pharisees' blindness was not their error. 'If you were blind, you would have no guilt'--i.e. if you were merely blind, or, if you knew yourselves to be blind. The Pharisees' problem was not that they were blind but that they thought they weren't--'you say, "We see."'
The mystery of the gospel, so deeply counterintuitive: guilt is taken away not in claiming sight but in acknowledging blindness. All because the one Person who ever came into this world truly seeing allowed himself, on a little hill, to be made blind, so that you and I, blind, can see, for free.