Patent systems are conventionally justified as a tradeoff: an inventor is granted a temporary legal monopoly over an invention in exchange for publicly disclosing how the invention works, so that the underlying knowledge eventually enters the public domain and other inventors can build upon it. Without this bargain, the argument runs, inventors would instead rely on trade secrecy, and the knowledge might never diffuse into the wider economy at all. An alternative account, drawn from the economics of innovation, questions how much genuine disclosure the patent bargain actually delivers in fast-moving technical fields. A patent's written description, this account observes, need only satisfy legal sufficiency, enough detail that a similarly skilled practitioner could, in principle, reproduce the invention, and firms have a documented incentive to draft that description as narrowly and ambiguously as the legal standard allows, since a broader, clearer disclosure would make it easier for rivals to design around the patented claim while still capturing the underlying insight. Where the pace of a field's advance outstrips the years-long process of examining and granting a patent, moreover, the disclosed information may already be technologically obsolete by the time it becomes public, further diminishing its practical value to other inventors. This account does not conclude that disclosure is worthless in every field; it instead implies that the disclosure benefit is likely to be smallest precisely where the pace of technical change is fastest, the same fields in which the monopoly cost of a patent, by foreclosing competitors during a period of especially rapid advance, may be highest. Which of the following best describes the function of the third paragraph in the passage?