The Good Book: Proverbs, chapter 19: Blindness

Lacking all irony, Grayling discusses blindness:

1. The sky is not less blue because the blind cannot see it.
True, but it’s hardly a nice thing to point out to them.
2. A pebble and a diamond are alike to the blind.
That depends on whether they want to cut glass or not.
3. Better be blind than see ill.
Truly? Seeing ill is curable.
4. Better half blind than both eyes out.
5. People are most blind in their own cause.
6. The blind eat many a fly.
Nice metaphor.
7. Blind men should judge no colours.
I think they know that
8. The eyes are blind when the mind is elsewhere.
9. Among the blind close your eyes.
Is this a “when in Rome…” thing? Because it seems dangerously unsafe.