Every patent system in the world requires an inventor to disclose his invention in the patent document. The courts rationalize this obligation as part of the quid pro quo of the patent system: the patentee must disclose the invention to the public in exchange for the patent's exclusive rights. The patent thus teaches the world about this new creation and enhances the storehouse of knowledge. The quid pro quo view of the patent system, however, is inconsistent with the theoretical justifications for patent law. Patents are meant to combat free-riding, yet this view of the patent as "teaching" the invention is based on the view that free-riding is normatively good. This article explains this apparent inconsistency by recognizing that the teaching function is not the primary purpose for disclosure. Instead, the purpose of disclosure, and specifically the manner of making the invention, is to demonstrate that the inventor was in possession of the invention. This shift in perspective from "teaching" to "possession" reconciles patent theory with the disclosure obligations and also provides significant normative power in explaining how patent law could work more effectively.