Sarah argues that a school policy requiring students to perform community service cannot, by itself, succeed in its goal of fostering a habit of volunteering in students. Why not? Because forced community service isn’t really “volunteering,” and you can’t foster a habit of volunteering in someone who’s never volunteered.

Paul disagrees with Sarah: he thinks a school policy forcing students to perform community service can single-handedly foster a habit of volunteering in those students. Why? Some students enjoy community service so much that they become volunteers. This is an example of the policy fostering a habit of volunteering.

We need to find a point of disagreement. Sarah and Paul disagree about whether or not a policy forcing students into community service can, by itself, foster a habit of volunteering in those students.