 As this brief survey makes clear, it is not obvious how to characterize what the ethical supervenes on, in a way that makes an ethical supervenience thesis both plausible and theoretically interesting. Now that the difficulties here have been made clear (especially by Sturgeon 2009), this is an important potential locus for future research. The following discussion largely sets aside these debates, speaking of the supervenience of the ethical properties on the base properties,where ‘base’ serves as a placeholder for a more illuminating characterization of the class of properties that subvene the ethical.