Document Type


Date of Degree

Spring 2016

Degree Name

PhD (Doctor of Philosophy)

Degree In


First Advisor

Richard Fumerton


In this dissertation I consider the problem of external world skepticism and attempts at providing an argument to the best explanation against it.

In chapter one I consider several different ways of formulating the crucial skeptical argument, settling on an argument that centers on the question of whether we're justified in believing propositions about the external world. I then consider and reject several options for getting around this issue which I take to be inadequate. I finally conclude that the best option available to us at the moment is to argue that the antiskeptical view is the best explanation of our ordinary experiences

In chapter two I argue that, if we hope to ground what counts as defending antiskepticism in common sense, there is an argument against the possibility of ever knowing one has succeeded in defending antiskepticism. After showing that common sense is no place to look in setting a goal for our antiskeptical project, I present the view that what will be crucial to settling on our antiskeptical goal is coming to a successful analysis of the nature of physical objects. I suggest some minimal criteria that must be met by a view in order to be antiskeptical based on our intuitions about core skeptical cases, but acknowledge that a fully successful response to external world skepticism will require the antiskeptic to engage in some much more difficult analysis.

In chapter three I consider various views of the nature of explanation and conclude, tentatively, that explanation as it interests the antiskeptic is fundamentally causal.

In chapter four I consider and reject some of the core views on which best explanation facts are so fundamental that a project of attempting to vindicate probabilistically the virtues which make explanations epistemically good. In this chapter I show that views which analyze justification in terms of best explanation factors fail.

In chapter five I attempt to vindicate the various explanatory virtues probabilistically. In doing so I attempt to express or translate the various explanatory virtues in terms of probabilities in order to show that having those virtues makes a view at least prima facie more probable.

In chapters six and seven I explain and evaluate the various arguments to the best explanation against skepticism present in current philosophical literature. I attempt to show that extant arguments fail to appreciate the virtues possessed by classical (and some new) skeptical scenarios.

In chapter eight I briefly consider some options that may be open to the antiskeptic moving forward. All routes forward contain considerable obstacles, but there are some fruitful areas of research to pursue.

Public Abstract

This dissertation considers the problem of external world skepticism. Some say that we have good reason to believe that the ordinary world of 3D objects exists. They argue that the ordinary world is the best method available to us to explain our ordinary experiences of walking around, going to work and driving our cars. I argue that those who argue this fail to appreciate how well views like the hypothesis that we're in a Matrix-world explain our experiences. As far as human beings are concerned, we're just as likely to be in the Matrix as we are to be in the real world.


publicabstract, abduction, antiskepticism, explanationism, inference to the best explanation, skepticism


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Copyright 2016 Bryan Christian Appley

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