Because custom is only vaguely defined with respect to its scope and content, this gives rise to the problem of erosion: people will bend the rules of custom in ambiguous cases by slightly underperforming or overperforming. This changes what is normal and thereby shifts the custom in response to other motives and incentives over time. A constraining custom must be expected to eventually disappear, for instance. Critical mass effects can be expected to be undermined by such erosion.
Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.
If you think you should have access to this title, please contact your librarian.