Note that the principles of circumscription apply in various ways in non-biological senses. In biological taxonomy the usual assumption is that circumscription reflects the shared ancestry perceived as most likely in the light of the currently available information; in geology or legal contexts far wider and more arbitrary ranges of logical circumscription commonly apply, not necessarily formally uniformly. However, the usage of expressions incorporating "sensu" remains functionally similarly intelligible among the fields. In geology for example, in which the concept of ancestry is looser and less pervasive than in biology, one finds usages such as: