[2iii] It was a secret, of which no one knows.
= [2iv] No one knows of this secret. (NOT: No one of this secret knows.)
In his answer above, why did Damkerng T. eliminate
No one of this secret knows.
? Why can't this possibility be deduced from the original pied-piped sentence?
Analogy
I reckon "No one of this secret knows." is one of the possible 2 ambiguities. Why? Just consider this analogous sentence #6!
- It was an (frivolous) organization,
ofwhich no one thinks seriously.
This is ambiguous as it can mean 6.1 and/or 6.2.
6.1. No member [
ofthis organization] thinks seriously.
To wit — all members of this organization are wacky, and are unable to think rationally.
AND
6.2. No one thinks seriously [
ofthis organization].
To wit — everyone knows that this organization is a joke. But 6.2 says nothing about whether its members are brainy or brainless!