In their seminal paper (ACM T. Softw. Eng. Methodol., 6(1) (1997), 1-30), Zave and Jackson established a core ontology for Requirements Engineering (RE) and used it to formulate the "requirements problem", thereby defining what it means to successfully complete RE. Starting from the premise that the stakeholders of the system-to-be communicate to the software engineer the information needed to perform RE, Zave and Jackson’s ontology is shown to be incomplete, in that it does not cover all classes of basic concerns - namely, the beliefs, desires, intentions, and evaluations - that the stakeholders communicate. In response, we provide a new core ontology for requirements that covers these classes of basic stakeholder concerns. The proposed new core ontology leads to a new formulation of the requirements problem.We thereby establish a new framework for the information that needs to be elicited over the course of RE and new criteria for determining whether an RE problem has been successfully addressed.