Document Type


Date of Degree

Spring 2012

Degree Name

PhD (Doctor of Philosophy)

Degree In


First Advisor

Cunning, David

First Committee Member

Fumerton, Richard

Second Committee Member

Fales, Evan

Third Committee Member

Hasan, Ali

Fourth Committee Member

Duerlinger, James


In this dissertation, I develop an interpretation of Leibniz on modality and free will. I do so for two reasons: first, I am attempting to revitalize the notion that Leibniz is the predecessor of contemporary modal semantics; second, I am using Leibniz's philosophical system to motivate responses to contemporary philosophical issues in modality and free will. In Chapter One, I argue that Leibniz's basic principles are plausible theoretical tools that ought to be used by contemporary philosophers in developing their philosophical systems. In Chapter Two, I develop Leibniz's views on the nature of individuals. I argue that possible individuals are actually of the same sort as individuals in the actual world--possible individuals and actual individuals are complete creatures that do not differ ontologically from each other. In Chapter Three, I argue that Leibniz's views on possible individuals make him a modal realist and compare his view with contemporary modal realism in order to support this claim. I also argue that counterparts avoid many of the problems set for them by contemporary thinkers; I end with the ways that Leibniz's view differs from contemporary accounts. In Chapter Four, I argue that Leibniz provides two different analyses of modality. The first is an infinite analysis account; the second is a possible worlds account. I argue that these two accounts are compatible and amount to two different descriptions of the same theory of modality. I address objections to each account in order to show this. In Chapter Five, I argue that Leibniz is a compatibilist about free will. Importantly, I argue that it is precisely Leibniz's account of modality that allows for this compatibilism, as against a necessitarian like Spinoza. I then use Leibniz's account to challenge contemporary libertarians about free will on the basis of the principle of sufficient reason. I also show how Leibniz can help semicompatibilism avoid a worry concerning necessitarianism. At the end of the day, I claim that adopting elements of Leibniz's system can help us better understand modality and the freedom of the will and can be an aid in furthering contemporary philosophical theory.


Compatibilism, Counterparts, Free will, Leibniz, Modality, Philosophy


vi, 219 pages


Includes bibliographical references (pages 214-219).


Copyright 2012 Seth Adam Jones

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Philosophy Commons