This paper examines Aristotle’s view that there are natural slaves, able-bodied people who lack the capacity to deliberate about the good and bad in life, who are ideally suited to be ‘tools of action’ for practically intelligent masters. After reconstructing Aristotle’s reasoning for the view that there are natural slaves in Politics i, and proposing a philosophical motivation for his interest in natural slavery, the paper reflects on what this case suggests about scholarly engagement with the political views of ancient philosophers when these are so contrary to our own.