1. Knowledge as justified true belief We have knowledge only when a proposition is believed to be true We have knowledge only when a proposition is believed to be true We have knowledge only when the believed proposition is in fact true We have knowledge only when the believed proposition is in fact true We have knowledge only when we have justification (or warrant) for our belief We have knowledge only when we have justification (or warrant) for our belief Edmund Gettier’s challenge: what must we add? Edmund Gettier’s challenge: what must we add?

2. Correspondence Theory of Truth Beliefs are true if they accurately represent the way the world is Beliefs are true if they accurately represent the way the world is Aristotle; Alfred Tarski Aristotle; Alfred Tarski What is this representation thing??? What is this representation thing???

3. Coherence Theory of Truth Beliefs are true if they are part of a coherent network of beliefs Beliefs are true if they are part of a coherent network of beliefs W.V.O. Quine’s “Web of Belief” metaphor W.V.O. Quine’s “Web of Belief” metaphor Disconnected from the world—do our beliefs now determine how the world is??? Disconnected from the world—do our beliefs now determine how the world is???

4. Reliabilist Theory of Truth Beliefs are true if they are generated by reliable belief-forming mechanisms Beliefs are true if they are generated by reliable belief-forming mechanisms How can this handle known errors? How can this handle known errors? What makes a belief-forming mechanism reliable??? A problem of circularity What makes a belief-forming mechanism reliable??? A problem of circularity Back to correspondence??? Back to correspondence???

5. Setting Standards: The Lesson of Rene Descartes Skepticism: denies that any of our beliefs genuinely constitute knowledge Skepticism: denies that any of our beliefs genuinely constitute knowledge Methodological Doubt: reject as false any view about which I may be mistaken Methodological Doubt: reject as false any view about which I may be mistaken

6. Goodbye to… Sensory data, including anything coming from experimentation and even sensations of my own body Sensory data, including anything coming from experimentation and even sensations of my own body Truths of reason, including mathematics and logic Truths of reason, including mathematics and logic

7. What’s left??? Descartes: I exist, and am a thinking being Descartes: I exist, and am a thinking being I can’t be wrong about that because I cannot doubt at all unless I exist and am a thinking being (CHEATING!!!) I can’t be wrong about that because I cannot doubt at all unless I exist and am a thinking being (CHEATING!!!) Tries to get the world back through God (CHEATING AGAIN!!!) Tries to get the world back through God (CHEATING AGAIN!!!) Are we even left with what Descartes gives us? (Critiques of David Hume, Friedrich Nietzsche and A. J. Ayer) Are we even left with what Descartes gives us? (Critiques of David Hume, Friedrich Nietzsche and A. J. Ayer)

8. The Lesson? Descartes sets his standards for knowledge so high that nothing, or at best, almost nothing, can reach them. Descartes sets his standards for knowledge so high that nothing, or at best, almost nothing, can reach them. Good news! We don’t have to accept the skeptic’s standard as Descartes does; and on their own grounds, they can’t convince us otherwise. Good news! We don’t have to accept the skeptic’s standard as Descartes does; and on their own grounds, they can’t convince us otherwise. We need to accept that knowledge involves fallibility. We need to accept that knowledge involves fallibility.

9. Sources of Knowledge Experience Experience Testimony Testimony Introspection Introspection Memory Memory Reason Reason