Xiao Zhang

Both motivational internalism and externalism need to explain why sometimes moral judgments tend to motivate us. In this paper, I argue that Dreier’ second-order desire model cannot be a plausible externalist alternative to explain the connection between moral judgments and motivation. I explain that the relevant second-order desire is merely a constitutive requirement of rationality because that desire makes a set of desires more unified and coherent. As a rational agent with the relevant second-order desire is disposed towards coherence, she will have some motivation to act in accordance with her moral judgments. Dreier’s second-order desire model thus collapses into a form of internalism and cannot be a plausible externalist option to explain the connection between moral judgments and motivation.

In this thesis, I explore motivational internalism and externalism, which concern the relationship between moral judgments and motivation. I first introduce the basic terms and different forms of internalism and externalism, including the externalist objections to internalism based on the famous counterexamples. I then argue against externalism by defending and developing Michael Smith’s fetishism argument. I not only respond to the externalist objections to the fetishism argument but also further argue against different externalist explanations of moral motivation that intend to avoid the fetishism charge. Finally, I re-examine different forms of internalism in order to argue for a new form of internalism that can better preserve our internalist intuitions whilst accommodating the externalist counterexamples. My ultimate conclusion will be that the most plausible form of internalism to accept is constitutional, unconditional, relatively strong, direct internalism that is formulated in terms of dispositional desires.