I'm not sure what Smith is saying, because I'm trying to listen to Levy and Bulcke, and from what I can gather, they're talking about the "essence" of creativity.
That essence, TK says, starts with the essence of the brand. It is then expressed by a "big idea" that makes a "bridge" between the consumer and the brand, based on its essence.
But the big idea, Bulcke says, doesn't necessarily have to be that large. In fact, he says, "it should be simple."
Creativity, in the final analysis, is expressing that simple, big idea into language that communicates the brands essence to the brand's consumers.
Well said, but somehow, I think Patti Smith would have expressed it just a little more poetically.