Psychologism in Logic: Bacon to Bolzano.- Between Leibniz and Mill: Kant’s Logic and the Rhetoric of Psychologism.- Psychologism and Non-Classical Approaches in Traditional Logic.- The Concept of ‘Psychologism’ in Frege and Husserl.- Psychologism and Sociologism in Early Twentieth-Century German-Speaking Philosophy.- The Space of Sings: C.S. Peirce’s Critique of Psychologism.- Quinean Dreams or, Prospects for a Scientific Epistemology.- Late froms of Psychologism and Antipsychologism.- Propositions and the Objects of Thought.- The Concepts of Truth and Knowledge in Psychologism.- Psychologism Revisited in Logic, Metaphysics, and Epistemology.- Why There is Nothing Rather Than Something: Quine on Behaviorism, Meaning, and Indeterminacy.- Cognitive Illusions and the Welcome Psychologism of Logicist Artificial Intelligence.