This chapter examines Plato’s Philebus as a valuable, though often overlooked, source for understanding the relation between knowledge and belief. Focusing on Socrates’ evaluation of different forms of knowledge, it reconstructs four central arguments concerning the status of belief in the dialogue. The Kinship Premise (11b–c) establishes the epistemic relevance of belief; The Double Ignorance Premise (48c–49a) highlights the danger of false knowledge claims; The τέχναι Argument (55c–59c) explores the variety of knowledge, including practical expertise; and The Price-Giving Argument (59e–66c) demonstrates the breadth of the concept of knowledge, extending even to certain forms of belief. The analysis concludes by addressing the four guiding questions of this study by drawing on the epistemological significance of δόξα in the Philebus.