Well that's exactly right, Min. You guessed an important implication of the move 'beyond' essence here. If there is no essence, then science itself doesn't have an essence. And if science doesn't have an essence, then it is impossible to state, once and for all, in an eternal list of properties, what science is. In other words, there is no possibility of securely grounding science in something eternal. Therefore what you call the "revisit of the academic body of knowledge" is indeed endless, endlessly creative, and contingent. This is roughly in keeping with Thomas Kuhn's argument in The Structure of Scientific Revolutions.