Conscience plays a central role in our moral lives. We have all felt the pangs of conscience when we fail to obey it; we are terrified by those who lack it; and we look to it as a moral guide, often using it to justify our actions. Yet there is little understanding of what it is, how it operates, and what justifications we have for obeying it.

The aim is to provide one plausible account of the nature and authority of conscience, that of Adam Smith. According to Smith, conscience, or what he calls 'the supposed impartial spectator', is the moral agent judging herself from the situation of an impartial spectator, just as she would judge others. Under this account, conscience is not an ideal or prototypical judge, but rather the agent judging as she would judge others. As a result, conscience is liable to all the same errors that any spectator is, especially partiality. Thus, there is a need to cultivate our conscience. We do so, I will argue, primarily through encountering diversity, which leads to disagreements, which prompt us to reevaluate how we judge others. Furthermore, Smith also claims that conscience has authority in virtue of the respect we give it. Our respect for conscience is rooted in our recognition that conscience is a better moral judge, demonstrated by our appeal to conscience to correct for our immediate, unreflective moral judgments. However, this account fails to capture a key feature of our phenomenological experience of conscience: conscience presents itself as the moral authority, not merely a helpful moral guide. I argue that Smith's theory, though not Smith himself, provides an alternative account of the authority of conscience: because conscience is our judging ourselves using our own faculties, we are committed to the accuracy of conscience's judgments the same way we are committed to the accuracy of all of our judgments.