How simple is the Humean Theory of Motivation?

In recent discussions of the Humean Theory of Motivation (HTM), several authors–not to mention other philosophers around the proverbial water cooler–have appealed to the simplicity of the theory to defend it. But the argument from simplicity has rarely been explicated or received much critical attention–until now. I begin by reconstructing the argument and then argue that it suffers from a number of problems. Most importantly, first, I argue that HTM is unlikely to be simpler than even close competing theories, and second, it is unlikely that a plausible version of the theory will be very simple. Moreover, I argue that a convincing case for HTM is likely to have to show that it is more virtuous than defenders have done so far.