Take the Joni Mitchell line:
Late last night I heard a screen door slam
and a big yellow taxi took away my old man
Now let your mind generate a variant:
Late last night I heard a GREEN door slam
And a big yellow taxi brought me a GREAT BIG CLAM.
And see if that variant is any good.
The model of creativity this presents us with is that our unconscious mind is constantly coming up with variations according to some formal restraints (in this case English with rhyme and meter) and presenting them to consciousness, and then we figure out if they are any good.
It’s a pretty good model of creativity except it doesn’t tell us:
(i)where the original constraints come from
(ii)where the variations come from
(iii)what it means for some versions to be good and others not and how we decide that.
Which, of course, are the only things we want to know.