Modalities in medieval philosophy

Studies in modal notions, such as necessity, possibility or impossibility, have always played an important role in philosophical analysis. The history of these conceptions is a fascinating story of a variety of assumptions which have given shape to one part of rational discourse. A typical modern approach to modality is codified in what is generally known as possible worlds semantics. According to this view, necessity refers to what is actual in any alternative state of affairs, possibility to what is actual in some, and impossibility to what is not actual in any alternative domain. The idea of spelling out the meaning of modal terms with the synchronic alternatives hardly occurred at all in ancient thinkers. They did not draw any sharp distinction between conceptual and real modalities and they were inclined to think that all generic possibilities must prove their mettle through actualization. Why and when did ancient modal conceptions and the modes of thought based on them lose their dominance? The main thesis of this book is that the idea of modality as multiplicity of reference with respect to alternative domains emerged in early medieval discussions and that it was originally influenced by the theological conception of God acting by choice. After a discussion of ancient modal paradigms, the author traces the interplay of old and new modal views in medieval logic and semantics, philosophy and theology. A detailed account is given of late medieval discussions of the new modal paradigms and attempts to apply them to modal logic, epistemic logic, and the logic of norms. These theories show striking similarities to some basic tenets of contemporary approaches to modal matters. This work will thus be of considerable interest to historians of philosophy and ideas, and philosophers of intensional logic and metaphysics.