A false promise and different moral explanations

In an invented ethics discussion, a student considers making a promise to return a borrowed book while already planning never to return it. The exercise stipulates that the owner would not lend the book if the true intention were known. One group evaluates the maxim and whether a practice of promising could survive the general adoption of such deception. Another considers likely effects on the owner, the borrower and futuretrust. A third asks what honesty, practical wisdom and the formation of character require. The teacher asks for an accurate comparison rather than a vote on which philosopher is mostlikeable. No claim is made that all possible realcases have identical consequences or that ethical judgment is reduced to this single classroom example. Students must distinguish a common conclusion from the different reasons that might support it and identify an objection fairly.