My interest in gathering together a collection of this sort was generated by a fortuitous combination of historical studies under Professor Keith Lehrer and studies in cognitive science under Professor R. Michael Harnish at the University of Arizona. Work on the volume began there while I was an instructor in the Department of Linguistics and was greatly encouraged by participants in the Faculty Seminar on Cognitive Science chaired by Professor Lance J. Rips. I wish to express my appreciation to all of these and to many other individuals with whom I discussed the possibility of contribution to this work. I am especially grateful to the authors of the essays included here, as they showed more patience than I could have hoped for in seeing me through a number of uncertain stages in development of the project. My thanks are also due to my colleague Charles Reid for assistance in reviewing submissions, to Tim McFadden for computer resources, and again, to Keith Lehrer for continuing advice in arrangements for publication. Financial support for manuscript preparation was provided in part under University Research Grant No. 617 from the University Research Council, Youngstown State University.