Passage Summary: Just because you can't do something doesn't mean you weren't supposed to do it; for instance, a traffic jam doesn't magically erase your obligation to keep a promise.

Conclusion: The rule that you only 'ought' to do what you 'can' do is sometimes false.

Reasoning: In the traffic jam scenario, the person still 'ought' to have met their friend even though they physically 'could not' do so.

Analysis: The ethicist is trying to prove that an obligation (the 'ought') persists even when the action is impossible (the 'can'). For this specific example to work, we must assume that the person still had the obligation to meet the friend despite the traffic jam. If the obligation vanished the moment the jam started, the example wouldn't disprove the principle. Look for an answer that confirms the moral duty remains intact regardless of external obstacles.