He Couldn't See At All

We paused at a traffic light, and a young Chinese man crossed the street in front of the car.
With a long white cane he slashed the air, probing all the possible obstacles that might be before him. The cane slid from side to side, and up and down, and it tapped the road gently.
At length the pedestrian shuffled away around a corner. The light turned green and off we went.
"Do you think," I said, "that he was completely blind?"
Spouse, only half-listening behind the wheel, was not certain of my meaning.
"The fellow with the cane," I said. "I was just wondering if he was completely blind, or if he might have partial vision. He seemed so young."
"Oh," said Spouse with an amiable shrug. "I didn't actually see him. Where was he?"
I stared.
"He walked right in front of us! He was waving his cane all over the place!"
Spouse shook his head. No, he had not seen such a person.
"How could you possibly miss him?" I demanded, flabbergasted. "How could you not... see... a blind..."
My words dwindled away there and then. I considered the matter. Evidently, Spouse did the same, for he gave me a most curious glance, which I returned twofold.
"That," I decided at last, "is enough discussion about seeing and not-seeing," and Spouse agreed it was far better left that way.