Given critical theory's current focus on the interaction between writers and readers over the surface of a text, it seems appropriate to examine the semantic component concerned with how writers anticipate that interaction--the interpersonal component. The relevance of the interpersonal component is apparent in traditional instruction on point of view and tone. Most composition texts encourage students to maintain a consistent point of view through consistent lexical and grammatical choices of a certain formality and purpose; many texts also encourage students to think of these choices within an initially determined rhetorical stance incorporating attitudes toward the reader and the subject matter. But the scalar nature of these choices reveals interesting information about why some shifts in point of view and tone are considered acceptable and others are identified as performance errors. An analysis of several text samples reveals that certain shifts do occur in "professional" texts, but that such shifts must be modulated in order to be acceptable; unmodulated, abrupt shifts will still be perceived as mistakes. Further, such shifts must occur within the limits of variation established at the beginning of a text. The treatment of point of view and tone as part of the interpersonal component of texts permits a more accurate description of shifts and a more precise explanation of the difference between acceptable and unacceptable shifts in point of view and tone. (Three text samples are appended.) (HOD)