This book was designed primarily as a textbook; though the author hopes that it will prove to be of interests to others beside logic students. Part I of this book covers the fundamentals of the subject the propositional calculus and the theory of quantification. Part II deals with the traditional formal logic and with the developments which have taken that as their starting-point. Part III deals with modal, three-valued, and extensional systems.

In this sketch of medieval philosophy I hope to show, more by illustration than by explicit argument, that philosophy did exist in the period from the first ...

Diversity, more often called numerical difference, is all-embracing and ubiquitous. Any entity (existent) of whatever category is diverse from any entity else. Diversity is also ontologically primary. All determinations depend upon it. Therefore, it is mistaken to define diversity as qualitative difference. Such a defintion is circular since qualitative difference is nothing but diversity of properties. This may be called into question by someone who conceives of qualitative difference in terms of negation.