In the resolution of ellipsis, a number of non-equivalencies between overt antecedents and their elliptical counterparts have been observed, most prominently by Fiengo and May (1994), who name this phenomenon 'vehicle change'. In this talk, I explore such deviances from identity in two domains of ellipsis: sluicing and comparative deletion. The cases of sluicing of interest here are those in which the antecedent contains a wh-trace, as in (1):
(1) We need to find out who left, and when.
I argue that the trace in the copied IP used to resolve the ellipsis is pronominal in nature, based on binding theory considerations and insensitivity to islands, and that this 'pronominal' variable is interpreted as an E-type pronoun, as in (2):
(2) We need to find out who [t left], and when [pro left].
The second domain comes from an investigation of attributive comparative deletion, and is based on joint work with Chris Kennedy. We examine the amelioration of illicit attributive comparative structures which occurs in the presence of ellipsis, as seen in the contrast between (3) and (4):
(3) Kim drives a faster car than Bill does.
(4) *Kim drives a faster car than Bill {owns/drives} a motorcycle.
These data, and additional data from pseudogapping, can be accounted for if the DegP in the antecedent can act as a pronominal variable in the ellipsis site. Again, this featural change will account for the observed insensitivity to islands. The analyses presented here, if correct, provide new evidence for a particular conception of deviance from identity under ellipsis: certain types of categories are equivalent to their pronominal correlates under ellipsis.
Ref: Fiengo, R. and R. May. 1994. Indices and Identity. MIT Press.