Washington Röbling’s Implicature

Speranza

The trustees are considering naming the Washington Roebling chief engineer.

TRUSTEE: 

You have never supervised anything of this scale and magnitude, Roebling, is that right?

ROEBLING: No one has.

H. P. Grice considers this in his Oxford lectures on conversational implicature (yes, he was using that phrase, 'conversational implicature' back then -- BEFORE Harvard).

Surely, Washington Roebling is being more informative than is required.

The implicature is:

Tricky!