Document Type : Research Paper

Author

• Mohammad Ali Ejeii

Professor of Philosophy, University of Isfahan

Abstract

In his book Asas al-ightibas Tusi speaks of a group of logicians who maintain that modality can be applied in order to modalize the quantity of a proposition. The standard view maintains that in a modalized proposition the modal term can only qualify the relation of the predicate to the subject. Avicenna has argued for the first thesis, and a group of well-known logicians followed him. Tusi disagreed. As Tusi precedes some of these logicians the question remains unsettled. The purpose of this article is to articulate the thesis first, and then to discuss Avicenna's reason for proposing it. The article argues that the data he offers in support of his thesis can be interpreted differently, and thus, it is argued that the thesis remains unjustified.

Keywords

• modalization of the quantifier
• modalization of the copula
• Avicenna