Psychologism in logic / Rolf George -- Between Leibniz and Mill / Carl Posy -- Psychologism and non-classical approaches in traditional logic / Werner Stelzner -- Concept of 'psychologism' in Frege and Husserl / J.N. Mohanty -- Psychologism and sociologism in early twentieth-century German-speaking philosophy / Martin Kusch -- Space of signs / Vincent Colapietro -- Quinean dreams or, prospects for a scientific epistemology / Michael Bradie -- Late forms of pyschologism and antipsychologism / Joseph Marolis -- Propositions and the objects of thought / Michael Jubien -- Concepts of truth and knowledge in psychologism / John H. Dreher -- Psychologism revisited in logic, metaphysics, and epistemology / Dale Jacquette -- Why there is nothing rather than something / Paul A. Roth -- Cognitive illusions and the welcome psychologism of logicist artificial intelligence / Selmer Bringsjord and Yingrui Yang