44 ROBERT D. VAN VALIN, JR.the actor is subject and the undergoer direct object, while in a passive the
undergoer is subject and the actor is in a peripheral PP. Since RRG is a
monostratal theory of syntax, it is not possible to capture these generaliza
tions by means of initial or deep grammatical relations, as in RelG or GB;
only a set of semantic roles more general than particular thematic relations
can express the relevant generalizations.
The relation between the two tiers is captured in the Actor-Undergoer
Hierarchy in (25).
This double hierarchy says simply that given the LS of a verb, the argument
bearing the thematic relation that appears leftmost on the cline will be the
actor and that the argument bearing the thematic relation that appears
rightmost on it will be the undergoer. This is the default situation. Marked
assignments to undergoerhood are possible, as in the "dative shift" alterna
tion in which the locative, not the theme, is undergoer, e.g. Bill [agent-
actor] gave Fred [locative-undergoer] the book [theme].
The ranking of thematic relations in (25) with respect to actor and
undergoer selection is supported by considerable cross-linguistic evidence.
The maximal unmarkedness of agent as actor and patient as undergoer fol
lows from the fact that if a verb has an agent argument, it will always be
actor, and likewise if one has a patient argument, it will always be under
goer. With respect to the actor end of the hierarchy, if a verb has both an
agent and an effector, as in Larry broke the window with a rock, the agent
must be the actor, never the effector, an observation that goes back at least
to Fillmore's original work on case grammar. Verbs like show ([do'(x)]
CAUSE [BECOME see'(y,z)]) which take both an agent or effector (depend
ing on the interpretation of the χ argument; cf. section 3.2, Holisky 1987) and
an experiencer (y) only permit the agent/effector to function as actor, never
the experiencer. The same is true of verbs like give ([do'(x)] CAUSE [BE
COME have'(y,z)]) which take both an agent or effector (x) and a locative
(y): only the agent/effector can be actor, never the locative. It is clear that