Did Varro think that slaves were talking tools?

This article challenges the widespread notion that Varro's Res Rustica 1.17 defined slaves as 'talking tools'. Instead, it argues that the genus vocale instrumenti comprised both slave and free workers within an economic unit. In this context, instrumentum does not mean 'tool', but what is needed to run a farmstead, including the human work-force, in accordance with the views that were prevalent among the Romans. Varro drew upon the agricultural literature of his time to build his threefold division of the instrumentum. His definition was unoriginal and void of any moral implications. As such, it has to be seen as a mere rhetorical device. What Varro attempted to do in this passage was to cast the pedestrian claim that human labour is needed to run a farmstead into a language that resembled an academic and philosophical discourse.