The Puzzle of False Belief: How Is False Judgment Possible? — Plato’s Theaetetus (Lecture 4)

Lecture 4 of "Plato’s Theaetetus: An Inquiry into Knowledge." In this fourth session on Plato's Theaetetus, Richard Polt traces Socrates' final arguments against the idea that knowledge is simply perception. The lecture examines how the psyche unifies consciousness across the separate senses, and why concepts like being, sameness, and goodness cannot be delivered by perception alone. These common concepts require reasoning that unfolds over time through education and effort. With perception defeated, the dialogue turns to a new proposal: knowledge as true judgment. But this raises an immediate puzzle. How is false judgment even possible? Polt walks through three arguments that seem to rule out false belief entirely, then introduces the wax block model of memory as Plato's attempt to rescue the possibility of error. The model works in some cases but ultimately breaks down, setting the stage for the dialogue's final move: the proposal that knowledge is true judgment plus an account, and the deep difficulty of defining what counts as a genuine account. Watch the full lecture series:    • Plato’s Theaetetus: An Inquiry into Knowledge   About this course Richard Polt leads a five-lecture exploration of Plato's Theaetetus, one of philosophy's most fascinating dialogues. The course takes up the fundamental question: what is knowledge? Theaetetus’s first proposal is that knowledge is simply perception. Polt traces how Socrates connects this idea to the relativism of Protagoras and the flux theory of Heraclitus, then dismantles it through arguments about expertise, self-refutation, and the role of the soul in grasping concepts. The inquiry shifts from perception to judgment, ending without a final answer. No prior background in philosophy is needed. About Richard Polt Richard Polt is a Professor of Philosophy at Xavier University. He holds a B.A. in philosophy from the University of California at Berkeley and a Ph.D. from the Committee on Social Thought at the University of Chicago. His interests include German and Greek philosophy, and he has taught courses on Heidegger, memory, history, technology, and African-American philosophy. Polt's publications include Heidegger: An Introduction, The Emergency of Being: On Heidegger's Contributions to Philosophy, and Time and Trauma: Thinking Through Heidegger in the Thirties. He has also edited or co-edited volumes including A Companion to Heidegger's Introduction to Metaphysics, Heidegger's Being and Time: Critical Essays, After Heidegger?, and The Task of Philosophy in the Anthropocene. Chapters 00:00 Recap: Four Arguments Against Relativism 02:14 The Final Argument Against Knowledge as Perception 03:01 The Psyche as Unifying Consciousness 05:23 Do the Senses Really Never Overlap? 09:57 Common Concepts Beyond Perception 12:50 Categories and the Empiricist vs Rationalist Debate 15:25 Why Separating the Senses Matters 18:41 Being: The Key Concept for Knowledge 21:21 Does Perception Share in Truth at All? 22:22 Knowledge as True Judgment 25:01 Theaetetus Disproves His Own Definitions 26:31 Anticipating True Judgment Plus Logos 28:11 Three Sophistical Arguments Against False Judgment 31:33 The Wax Block Model of Memory 35:08 How the Wax Block Explains False Judgment 40:13 Where the Wax Block Model Breaks Down 42:42 The Nature of Truth and Being 45:16 Preview: Can Knowledge Be Defined? Presented by Ergo, a nonprofit that publishes in-depth philosophy courses taught by leading scholars. Every course is freely available. https://ergo.org Connect with Ergo: Subscribe:    / @ergo_org   Instagram:   / ergo_org   LinkedIn:   / ergoorg