Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)



Committee Chair

Michael Bergmann

Committee Member 1

Patrick Kain

Committee Member 2

Paul Draper

Committee Member 3

Matthias Steup


This dissertation is an attempt to apply the Moorean response to radical skepticism to moral skepticism. In a nutshell, I argue as follows. Assume that the following Moorean response to, say, BIV skepticism (the worry that I don’t know I’m not a brain in a vat) is roughly correct: “I know I have hands, so I’m not a BIV; any argument to the contrary must have a flaw somewhere.” If so, then such a Moorean should respond as follows to moral skepticism: “I know that recreational genocide is wrong, so it’s false that there are no moral facts, and that I don’t have any moral knowledge; any argument to the contrary must have a flaw somewhere.”

In chapter 1, “Moore for Almost Everyone,” I explicate the Moorean response to radical skepticism. I begin by outlining the main responses to skepticism currently on offer, and then move to a discussion of Mooreanism. I argue that Mooreanism is a metaphilosophical response to skepticism that essentially boils down to these two claims: (i) it is more rational for us to believe in the Moorean truths than it is to believe the conjunction of the skeptic’s premises (a conjunction which entails the negation of a Moorean truth), and (ii) in virtue of (i) we can use our knowledge or justified belief in Moorean truths to provide a rational basis for rejecting skeptical premises. I proceed by discussing what it is to be a Moorean truth as well as how my conception of Mooreanism fits within the commonsense tradition.

Chapter 2, “Metaethical Mooreanism,” extends Mooreanism to the metaethical dispute regarding whether we have moral knowledge. I begin by arguing that there are good reasons to include some moral truths in the domain of Moorean truths. I then spend a significant chunk of space applying metaethical Mooreanism to the evolutionary debunking argument. What we see in this investigation is that the evolutionary debunker has need of a host of controversial commitments, a bloated conjunction which is epistemically inferior to Moorean moral facts. I close by responding to Tristram McPherson’s objection to the Moorean strategy, which boils down to the claim that there are evidential asymmetries between the two skeptical contexts which prevent the successful application of Mooreanism to the moral domain.

In chapter 3, “Moore on the Problem of Moral Disagreement,” I apply metaethical Mooreanism to the problem of moral disagreement. I begin by giving a brief overview of the problem, after which I explain metaethical Mooreanism and show how the metaethical Moorean will look at the problem of moral disagreement. The basic idea is that the skeptic’s argument from moral disagreement fails in the same way that arguments for radical skepticism fail, including skeptical arguments from disagreement: they are less rationally compelling than the Moorean truths they seek to overturn. No Moorean should stop with this metaphilosophical assessment, however; rather, Mooreans need to go on to diagnose which premise(s) in the skeptical arguments are false. My diagnosis challenges two of the skeptic’s assumptions: (i) that we are in a position to say who our moral-epistemological peers are, and (ii) that there is significant disagreement on the metaethical question of whether there are moral facts.

In the final chapter, “Moore on the Argument from Empirical Moral Psychology,” I apply metaethical Mooreanism to the alleged skeptical problem generated by empirical moral psychology. Roughly, the problem is that we seem to form many of our moral beliefs on the basis of our emotions, which are held to be epistemically suspect bases. After a discussion of the problem I show how the metaethical Moorean will look at the matter. The point the Moorean makes here is the same point the Moorean makes in defense of other Moorean truths: the Moorean truths have more going for them, epistemically, than do the skeptic’s premises. The Moorean will not stop here but will go on to give a diagnosis of the problematic premise(s) in the skeptic’s argument. I carefully work through the skeptic’s argument from empirical moral psychology, ferreting out the controversial requirements needed by the argument. What we see once again is that the moral skeptic relies on a nest of controversial philosophical principles that pale in comparison, epistemically speaking, to Moorean moral facts, such as that recreational genocide is wrong. At the end of the day, our knowledge of such moral facts is as epistemically secure as our knowledge that we have hands.