Sylvan's theory of 'plurallism', the culmination of his life's work, is the subject of this important text. In his own characteristically provocative words 'There is not merely a plurality of correct theories and more or less satisfactory worldviews: there is a corresponding plurality of actual worlds. Plurality penetrates deeper in full plurallism than linguistic surface or than conceptual or theoretical structure, to worlds… There is no single fact of the matter, there are facts and matters.' First published by The White Horse Press in 1997, this facsimile reprint has been made using a scan of the original published edition generously provided by McMaster University Library.