ions. This shifts the burden of proof onto Humeans to motivate their more restrictive, revisionary account. Second, I show that they are unlikely to discharge this burden on empirical grounds, whether by appealing to research on neurological disorders (acquired sociopathy, Parkinson's, and Tourette's), the psychological properties of desire, or the scientific virtue of parsimony. 9. Defending Virtuous Motivation Abstract: This chapter considers whether there is empirical evidence that we're rarely virtuously motivated-i.e. rarely do what's right for the right reasons. There are two key challenges that threaten to "defeat" claims to virtuous motivation: self-interest and arbitrary situational factors. The structure of these threats is similar to the debunking arguments from Ch. 4: defective influences on moral behavior make us motivated by the wrong reasons. The motive of selfinterest is indeed powerful and rationalization is rampant. Still, there are limits to egoism and Regard for Reason / Synopsis / pg. 5 of 5 arbitrary influences, as exemplified by experiments on cheating and dishonesty. Ultimately, like debunking arguments, defeater challenges succumb to a Defeater's Dilemma: one can identify influences on many of our morally-relevant behaviors that are either substantial or arbitrary, but not both. Our best science so far suggests a trade-off: substantial influences on many morallyrelevant actions are rarely defective. 10. Cautious Optimism Abstract: This chapter serves as a brief conclusion with a recapitulation of the main claims and moves made in the book and a discussion of some implications. The best defense of our moral minds yields a cautious optimism. Ordinary morality is capable of rising to knowledge and virtue, because we do have a regard for reason, but we do often fail. When we do fail, though, the problem is not typically commonsense morality itself, but our poor reasoning from it. One broad implication of cautious optimism is that the best method for making more of us more virtuous will not ta