Anne is a Professor of Cognitive Science, teaching at a venerable British University in the 1980s. In the Spring, her course on the Philosophy and History of Psychology finds strange and often hilarious echoes in her own life. She is obsessed with solving two mysteries. One is profound and has exercised many a philosopher since Descartes: how can she tell when she is dreaming? The second is scandalous: who could have left the lurid descriptions of an extra-marital affair on her laptop? As Anne muddles distractedly through the term, she tries to apply what she has learned in her scholarship about evidence. In the process, human reasoning is revealed to be riddled with pitfalls.