Passage Summary: We follow laws for the same reason we don't eat with our hands at a fancy dinner: it's just the custom. It's not about being 'good' or avoiding a fine; it's just about doing what is usually done.

Conclusion: Societal laws are primarily followed because they have become customary habits rather than due to ethical concerns or fear of punishment.

Reasoning: The author compares laws to manners, noting that manners are followed through repetition and the fact that acting otherwise becomes unthinkable.

Analysis: This argument uses an analogy to explain a social phenomenon. By identifying a shared characteristic between manners and laws—that both are types of social conduct—the author argues they share the same underlying motivation. To identify the method of reasoning, focus on how the author uses the 'manners' example as a template to explain why people obey the law. The core of the argument is the comparison between the reasons for following two different sets of social rules.