Introduction I. Vatol's anxiety Introduction to Lev's question The example of Vatol Yitzhak's reaction to skepticism, and Williamson's On the nature of this work The "two-level" view of the impossibility of doubt The meaning of "reasons" to doubt Relationships between "doubt", "belief", "assertion", and "certainty" Further connections between "doubt", "anxiety", and "knowledge" Interlude: Waiting for Godot A connection to Nagel's skepticism Interlude: philosophy and comedy A challenge to Lev's assumptions about epistemic anxiety II. Vatol and Us The n-to-n+1 argument A safety condition on belief Interlude: memories of Berkeley Pryor's epistemic principle Distinction between one-level and two-level cases Interlude: Talmudic connections The "non-circularity" condition Daniel 's challenges to Yitzhak's view Yitzhak's stringent response to "entering a loop" Yitzhak's Austinian answer to the problem of dreams Interlude: finding an "eitzah" Daniel's two additional questions Summary Lev's disagreement with Yitzhak III. The Impossibility of Doubt Lev's past epistemic anxiety Interlude: Memories from Yeshiva Lev's first argument for the impossibility of doubt The first premise of Lev's first argument A question about valuing one's life on the basis of probabilities A comparison of Lev's position with Kant's and Wittgenstein's Interlude: Yitzhak's tale Lev's second argument The meaning of "having a self" Interlude: Yitzhak's pride and shame Relationship between the notions of "self" and "identification" Broughton's suggestion that Hume did not identity with his belief in an external reality Lev's epistemic attitude Endnotes References.