Weak Crossover as aScope Phenomenon E. G. Ruys Thisarticle investigates the proper characterization of the condition thatis responsible for weak crossover effects. It arguesthat the relevant conditionbelongs to scope theory and that weak crossover arises from theway in which scope is determined in syntax. This implies that weakcrossover can occur whenever an operator must take scope over apronoun,even when the pronoun and the operator are not coindexed andthe intended interpretation of the pronoun is not as a variable boundby the operator. It also implies that, when an operator is for somereason assigned scope in an exceptional manner and escapes theusual syntactic restrictions on scope assignment, bound variable licensingwill be exceptionally allowed as well. Keywords: weakcrossover, scope, variables, binding 1Introduction Considerthe examples of strong crossover (SCO) andweak crossover (WCO) in(1). (1) a. Whoi ti likes hisi mother? b. *Whoi does hei like ti ? c. ??Whoi does hisi motherlike t i ? In(1a) itis possible for thepronoun to be interpreted as a variablebound by the wh-operator, yieldingthe interpretation ‘ for whichperson x, x likes x’smother’. In(1b) and (1c) asimilar readingis unavailable. At firstglance the last two examples resemble (2) (see Chomsky1977), whichalso excludes a boundvariable reading for thepronoun. (2) ??Everysoldier i hasa gun.But will he i shoot? However,(2) isusuallygiven a differenttreatment than the examples in (1).The operator in (2) doesnot take scope over the pronoun, so the unavailability of thebound reading in this case may simplybe attributed to the fact that, as a matterof logic, operators can only bind variables in theirscope. In (1), on theother hand, the operators c-command the pronouns. By currenttheories ofscopeassignment, this means that the operators do take scope over the pronouns. The absence Iwouldlike to thank Jan Don,Johan Kerstens, Iris Mulders,Ad Neeleman, BillPhilip, Tanya Reinhart, Maaike Schoorlemmer,Henk Verkuyl, Fred Weerman, YoadWinter, audiences at Utrecht University,Tilburg University, Potsdam University,and CUNY, andanonymous LI referees forhelpful comments andsuggestions. All remaining errors are my own. Linguistic Inquiry, Volume 31, Number 3,Summer 2000 513–539 q 2000 bythe Massachusetts Institute ofTechnology 513 514 E . G . R U Y S ofvariablebinding in (1b–c) thusappears to revealthat a boundvariable pronoun not only must bein the scope of the operator, but also is subject to some additional, presumably syntactic constraint. Thesyntactic generalization governing the facts in (1) hasoften been characterized as follows: pronounsthat are coindexed with operators must be locally A-bound, or alternatively,operators mustnot locally A ¯ -bindpronouns. Many principles of grammar havebeen proposed that express thisbasic generalization. It is well known, however, that this generalization does not cover the fullrange of relevant examples; various refinements have been introduced to dealwith different typesof counterexamples. Below, I willdiscuss several classes of such counterexamples. My investigationof these nonstandard cases will lead to a generalconclusion regarding the proper characterizationof crossover,which I willoutline here. Mostanalyses of crossover assume that an operator and a pronounare subject to WCO only if theyare coindexed. For instance,(1b) and (1c) areill formed only on the intended reading indicatedby the indexing subscripts; otherwise, the operator is free tocross over the pronoun. Hence,crossover conditions are usually formulated as applying to coindexed operator-pronoun pairs.Such conditions typically make use of notions borrowed from someexisting module of grammar thatemploys the coindexing relation: binding theory or, sometimes, movement theory. 1 Insome cases the crossover condition is actually incorporated into binding theory. 2 For ease of reference,I willrefer toall such conditions as binding-theoretic conditions. Below,I willpresent several classes of exampleswhere an operator and a pronounare not coindexed,but we stillfind a ‘‘WCO configuration’’— inthe sense that a particularreading of thesentence is available only if the operator c-commands the pronoun from anA-position, and isunavailable if theoperator merely c-commands the pronoun from anA ¯ -position.I willargue thatthis is thecasewhenever that reading depends on the operator’s takingscope over the pronoun. Naturally,one might claim that in allsuch examples the operator and the pronoun really are coindexed.But the question then arises how we canprovide independent evidence that a pronoun andan operator bear the same index in a givenstructure. In the relevant examples the pronoun isnotinterpreted as a variablebound by the operator: they are not coreferential or ‘‘covalued.’’ Nonetheless,one might still claim that some coindexing relation obtains, but that the relevant coindexingrelation does not denote coreference or covaluation. Of course,this is a gratuitous move,unless one can demonstrate the presence of these indices by some other means— for in- stance,by showing that they are visible to Condition A, B,orCofbinding theory. I willargue 1 Someanalyses thatreturn to a movementtheory perspective of crossover(see Postal1971) are May’s (1985)path- theoreticaccount, Ruys’ s (1994b)analysis that derives WCO fromChomsky’ s (1993)Shortest Link, and the analysis proposedby Georgopoulos(1991). See Ruys1992 for a discussionof May1985 and other references mentionedin the text. 2 Forexample, Reinhart 1983, 1987, Koopman and Sportiche 1982, Ha ¨õ k1984,Safir 1984, 1996, Stowell, to appear. Someauthors, notably Higginbotham (1980, 1983), have described the phenomenon in terms ofconditionsand relations thatare onlyindirectly related tobinding theory (e.g., Higginbotham’ s Dependenceand the associated Accessibility Condition).The problem with such an approach is thatit begs the question of whythe proposed condition has theproperties itis definedto have, and why it applies to the class ofrelationsit issaidto apply to. I willreturn to such binding theory extensionsbelow. WEAKCROSSOVERASASCOPEPHENOMENON 515 thata WCO configurationsometimes obtains between a pronounand an operator that are not ‘‘related’’ inany way (coreferentiality, binding theory) except that the operator, in the intended reading,takes scope over the pronoun. Iwillthus argue that the binding-theoretic approach faces severe empirical inadequacies. I proposeinstead that the condition responsible for WCO belongsto scope theory: both (1b –c) and(2) reflecta failureon the part of the operator to take scope over the pronoun. I willargue thatthis view holds the promise of aprincipleddefinition of the class of pronoun-operator pairs thatare subject to WCO. 3 Somany different ‘ ‘weakcrossover conditions’ ’ havebeen proposed in the literature that spacedoes not permit me to discuss each of themseparately. Indeed, this is not strictly necessary, asI aimto argue against whole classes of weak crossover conditions. The exact way in which myarguments apply to each particular implementation known from theliterature must be leftfor thereader to verify (see, however, footnote 21, and Ruys 1992:chap. 4). Inorder to facilitate the discussion, I willformulate two ‘ ‘straw man’’ theoriesof thekind Iwillargue against. Two such straw menare needed, as the class of analyses I argueagainst dividesinto two separate subclasses that are affected by my arguments in different ways. These straw mantheories are stated in (3). (3) a. Binding-theoreticlicensing principle PronounB maybe interpreted as a variablebound by A onlyif A A-bindsB. b. Binding-theoreticconfigurational principle PronounB maynot be locallyA ¯ -bound. Twotypes of crossover principles are distinguished here, which I willrefer toas licensing princi- ples and configurational principles.Licensing principles, in this sense, state that for apronoun tobe interpretable as a boundvariable, it mustenter into a licensingrelation with some (operator) expressionat some stage in the derivation. In this manner, the bound variable interpretation is ruled in undercertain conditions. This category includes the proposals in Higginbotham 1980, 1983and Reinhart 1976, 1983. The licensing principle (3a) isbasically Reinhart’ s condition. Configurationalprinciples, on the other hand, state that a pronounmay not enter into a given relationshipwith any (operator)expression at a givenstage in the derivation. In this manner, structurescontaining a boundpronoun are ruled out undercertain conditions. This category in- cludesthe proposals in Koopman and Sportiche 1982 and Safir 1984.The configurational principle (3b)is basicallyKoopman and Sportiche’ s BijectionPrinciple. Whatthe two conditions in (3) havein commonis thata pronounand an operator must obey them,on pain of producing a WCO violation,just in case the pronoun and the operator are 3 As forthe WCO/ SCOdistinction, there is disagreement intheliterature about whether these phenomenashould begivena unifiedaccount. Reinhart (1983), for example, excludes (1b) and (1c) with the same condition.The Bijection Principle(Koopman and Sportiche 1982), on the other hand, does not exclude (1b); this example isinsteadconsidered tobe aConditionC violation.The crossover account to be developed here rulesout WCO andSCO in the same way. ButSCO configurations presumably display a ConditionC effect inaddition to the crossover effect. Althoughnothing hingeson this,I willrestrict attentionto WCO configurationsso as topreempt any interfering Condition C effects. 516 E . G . R U Y S