That's from the "Nice version". The "Mean version" no longer seems to be available on the web for free, but I read it years ago. In the "Mean version", he points out that many showrunners feel they're impostors. A showrunner who says "I'll know it when I see it" is an impostor, because their job is to have a clear vision of the project and be able to communicate it to the crew.
Ah. Thanks. Here's the "mean version" of the quote to which I was referring:
Well... it is true that not everyone believes that knowing what
they want, and reaching out to those who need to know it in order
to perform, is a necessity for success in the world of
television... and this is the part where they come out from their
slimy, shit-stained hole and excuse their lack of vision (or
their unwillingness to impart that vision) with a defense I
consider to be the most cowardly and thieving seven words in the
showrunner's lexicon:
"I'll know it when I see it."
If you ever find yourself saying that, kindly consider the
possibility that - and I mean this, from the heart - your
impostor syndrome is most likely real and you are, in fact, a
shrill, shrieking fraud.
