 The description versus prescription contrast also comes into play in relation to the different kinds of meaning given to the genotype-phenotype distinction. Should philosophers descriptively trace the shifts in meaning from Johannsen to the current day, or should they prescriptively disambiguate different meanings that may coexist among the work of different groups of researchers or even within a given group (see entry on  ambiguity)?  Or should it be simply and descriptively noted that coexisting meanings make the genotype-phenotype distinction a “boundary object” that allows various fields (or “social worlds”) to interact even though the fields use the term to different ends (Star &amp; Griesemer 1989)? Perhaps the different meanings given to the term serve as a reminder of the disunity of science that follows once rationality and objectivity are seen not as “universal or necessary [matters], but local and contingent, relative to scientific interests and purposes” (entry on  the unity of science;  Cartwright 1999). Descriptively, philosophers could tease out the different, sometimes incommensurable, interests and purposes that make a line of inquiry rational. Prescriptively, they may highlight where they disagree with a given field’s interests and purposes, but they could also advocate pluralistic acceptance of different sciences that reflect 