Moliere was not above writing it, and that says everything. But even if Moliere had not written it, would another have been wrong to think of it? O critics, narrow minds, men of little sense, how long will you refuse to judge something for itself, and not approve or disapprove of it only in relation to what exists!
This is frustrating: it works as a strong guide for critical response, but struggles as a dramaturgical statement. Admittedly, Diderot is condemning the failure of critics to address a performance on its own terms, rather than suggesting that 'past performance does not guarantee future returns', but it praises a theoretical assertion over the value of experience.