PRO and subject of NP

E D W I N W I L L I A M S

P R O A N D S U B J E C T OF NP*

In this note I will review some evidence bearing on the idea that an NP has a 'controllable' PRO subject in specifier position (called here the 'NP PRO' view or theory). Here, as in Williams (1982), I will conclude that PRO and syntactic control are not a part of the analysis of NPs. I will also try to give an alternative account of the things that would seem to support an analysis that posited NP PRO.

The broadest conclusion that could derive from this effort would be that NPs and Ss are utterly different in the important respect that Ss, but not NPs, have 'subjects', since if NPs do not have subjects, then of course they do not have PRO subjects; this was the conclusion of Williams (1982). In the present paper I will in fact address only the question whether the NP PRO hypothesis receives support.

0 . T H E P R O S U B J E C T T H E O R Y OF N P s

There are a number of attractive reasons for positing a PRO subject of NP:

(1) NP

PRO N'

Perhaps the simplest reason is to account for the meaning of NPs in certain contexts:

(2) The leaves curl during maturation.

Here one understands that the leaves curl during the leaves' maturation, and this can be attributed to control of a PRO in the specifier of the NP [PRO maturationN,]m,, control by the subject NP the leaves, especially

* This note is a response to a theory of NP PRO outlined by Chomsky in class lectures in the Fall of 1984; the discussion in section 0 is partly my reconstruction of his remarks, and in part my own elaboration. I mean of course for my conclusions to hold against any version of such a theory. I have benefited from discussion of these issues with Andrew Barss, Noam Chorusky, Jim Higginbotham, and Howard Lasnik. For an extensive discussion of the question of control of purpose clauses, see Lasnik and Williams (in progress). I am especially grateful to Tom Roeper for nearly talking me out of the herein expressed views several times in the last two years, and for raising these issues in the first place.

Natural Language and Linguistic Theory 3 (1985) 297-315. 0167-806X/85.10 © 1985 by D. Reidel Publishing Company

2 9 8 E D W I N W I L L I A M S

since a full NP in the position of the specifier gets the 'subject ' interpretation: ' the leaves' maturation'. Example (2) Would be completely parallel to The leaves curl while PRO maturing, a case that undoubtedly involves control of PRO. Already there are grounds for caution, though, for as Williams (1982) showed, the control in the two cases works differently:

(3)a The leaves should not be bothered while dessicating. b. The leaves should not be bothered during dessication. c. *You should not bother the leaves while dessicating. d. You should not bother the leaves during dessication.

Example (3) shows that control in the case of the gerund is restricted to surface matrix subject, whereas control of the NP PRO could be subject or object. This difference already makes the NP PRO suspect.

Other related reasons for positing PRO in NP have to do with control (by the PRO, as well as of the PRO), and conditions B and C of the binding theory:

(4)a. Any PRO attempt PRO to leave (will be thwarted).

b. They heard PRO stories about them. c. The PRO realization that John was sick upset him. d. The PRO realization that he was sick upset John. e. They heard PRO stories about themselves.

In (4a) the 'at tempter ' is understood to be the same as the ' leaver' - this could be a consequence of control of the infinitive PRO by the NP PRO; in (b) them is understood as different in reference from the teller of the story - this could be due to condition B assigning disjointness between them and the PRO in the specifier, to which is assigned the theta role of 'teller'. Finally, in (c) we understand that John is not the 'realizer' - here condition C applies between PRO and John. Compare this to (d).

There are several different ways to instantiate a theory of PRO in NP.

All of them have in common that PRO is in a syntactic position in NP, and the same rules that apply to syntactic positions in S also apply in NP. It is this core of the idea that I will try to show is wrong, first by displaying cases that none of the instantiations can deal with, then by outlining the system of principles which does appear to govern the relevant facts, a system that is written not in terms of syntactic positions, but rather in terms of 'implicit arguments ' in the sense of Roeper (1983) and Roeper and Keyser (1984).

Suppose that a controllable position is generated in the specifier of NP (where genitives would otherwise appear). Several questions must be answered before a reasonably concrete theory is arrived at. First, is the

P R O A N D S U B J E C T O F N P 299

PRO always present in that position when a lexical NP is not there, or is a null specifier possible as well? Second, is the PRO obligatorily controlled when it appears, or is it liable to 'discourse' or 'arbitrary' interpretations? And third, when the PRO is controlled, what are the principles establish- ing control? Certain of the explanations already given force answers to some of these questions. So, in order to establish disjointness in (4b), we must assume that the PRO is obligatorily present at least in some circumstances, for no prediction is made if PRO is absent; similarly for (4c). And in order to account for the interpretation of (4c), we must assume the control to be obligatory there; but of course it must be optional for (4b), otherwise they would necessarily be understood as the 'tellers'. In (4b), on the other hand, PRO appears to get a definite 'discourse' referent, despite the presence of a c-commanding controller. Example (4e) would seem to require that NP have no PRO in the specifier, for if it did, the PRO would have to control the reflexive and be controlled by they, but this would imply that they would correspond to the 'teller' role of stories, which seems wrong for this example.

These remarks are difficult to sum up. It seems that the PRO is obligatorily present at least in some cases, and when present, is sometimes obligatorily controlled and sometimes not. This messy description of the facts here should not be taken as an implicit argument against or disparagement of the NP PRO idea; I simply want to show that in eval- uating the general idea of NP PRO, (or any other account of these facts, including my own) there are a number of important questions about how to develop such a theory that remain open, and that consequently one must be especially careful that conclusions are targeted on the main idea. However these questions are sorted out, I take the main idea of the NP PRO theory to be that there is a syntactic controllable position in the specifier of at least some NPs.

My challenge to this kind of theory can be summarized in the following way: the cases that could be cited to support the idea that NP has a PRO specifier actually fall under generalizations that apply to ALL (non- phonologically realized) arguments in NP, not just to the ones that can be associated with the specifier position of NP. If this is so, then of course it is useless to posit PRO in NP.

1. CONTROL OF NP P R O

The PRO theory accounts for the fact that John is understood as corresponding to the 'maker' argument of picture:

(5) John took a PRO picture of Mary.

PRO is assigned the role, as any NP in the specifier would be, and John

300 E D W I N W I L L I A M S

controls the PRO. The control is obligatory for this verb, though of course not in general.

But the usefulness of positing PRO in these cases is immediately cast in doubt by cases which appear to involve the same phenomenon as (5), but to which the account of (5) just mentioned cannot be extended:

(6) John took Mary's picture (t).

Here, the specifier is occupied by Mary and so PRO cannot occur, yet John is understood as the maker here as well. So there must be some way to directly establish this link between John and the Maker role, in- dependent of and not mediated by PRO. But then of course we most likely will not need PRO in the case of (5), either.

The minimum a theory must do is associate the subject of take with the Maker role of the object of take. We might suppose that this is done directly, in the sense that part of the meaning of take is that its subject is understood as filling its object's Maker role. Since the Maker role in the object is not expressed, and cannot be PRO (at least not for all cases - e.g., not for (6)), we must suppose that even the unexpressed arguments (the IMPLICIT ARGUMENTS, in the terminology of Roeper (1983)) must be 'visible' for the purposes of these relations.

The Maker role can be expressed internal to the NP, apparently without affecting the nature of the association just described:

(7) John took his first picture yesterday.

In (7) his is assigned the Maker role, and John is associated with the Maker role - there is apparently nothing that bars this double specification, or bars coreference between John and his.

As a concrete instantiation of the kind of association we have been discussing, we will use the following mechanisms:

(8) Lexical items have a list of arguments, and these arguments are syntactically visible:

give (Agent, Theme, Goal)

(9) Furthermore, a verb can specify 'associations' between its arguments and their argument structures:

take (Agent, Event) the agent is associated with maker role of the event

John took a picture I I

(Agenti, Event) (Makeri, Subject)


We have used coindexation of argument slots to indicate the association effected. In some sense this is a 'null hypothesis' since it simply gives the links between arguments directly, and does not posit that these links are mediated by any other kind of mechanism. The rule illustrated in (9) is like a rule of control, but is not one in fact, since it does not concern syntactic positions, but rather arguments (or argument slots) as they are marked in the argument structure of predicates, whether or not these arguments are linked to syntactic positions (when they are not, they are 'implicit').

To summarize the discussion so far, we have seen two reasons not to posit PRO in NP. First (section 0, example (3)) the control of such a PRO is not by the same principles that govern control of S PRO. Second, positing PRO necessarily gives only a partial answer to the question of what associations are possible between matrix and NP arguments.

I have outlined a 'null hypothesis' (i.e., (9)) about how such association works, which will serve as a point of reference in further discussion. We will call this hypothesis the "implicit arguments" hypothesis, adepting Roeper's terminology.

Some further evidence against the PRO theory derives from the fact that with different verbs, we find different arguments of the embedded nominal controlled. So, for example, while tlae verb take specifies association of its subject with Agent or Maker roles, the verb undergo seems to specify Patient roles:

(10)a. Johni underwent an operation.

I (Actor, Patienti)

b. Johni performed an operation. I

(Actor~, Patient)

Perform is the opposite of undergo, specifying association with the complement's Actor role. Submit NP to, like undergo specifies association with the Patient (though in this case it is the matrix object, not the subject, which is associated):

(11) Johni submitted himself to her scrutiny (of himJ*Bill). I

(Actor, Patient~)

The importance of these examples is that they emphasize that it is a n association between particular arguments that is taking place, not an association between particular syntactic positions - even when, as in the


matrix sentences above, certain arguments are expressed and occupy particular syntactic positions. In (11), for example, PRO cannot be used to mediate the relation between John and the Patient role of scrutiny, since the specifier is filled and so PRO is precluded. The matrix object is associated with the Patient role of the complement noun, whether that role is actually expressed or not.

This kind of association is strikingly different from control of PRO in Ss in that it is seemingly indifferent as to how various argument positions are syntactically realized, and in fact to whether they are realized, but it is quite particular as to the type of argument that gets controlled. Control of PRO in S is exactly the opposite.a

2. CONTROL BY NP P R O

In this section we will examine the role of PRO in NP not as a controlled element, but rather as an antecedent of control relations. As before, we will see that the relevant relations are indifferent to syntactic positions, and completely tuned to the thematic nature of arguments, be they expressed or not, in specifier or not, and so PRO will again seem an inappropriate way to mediate the relation.

The basic fact to account for is that in the following the 'attempter' is understood to be the same as the 'leaver', as mentioned earlier in connection with (4):

(12) Any PRO attempts PRO to leave.

Positing PRO in NP in these cases will not answer the full range of questions that must be answered, as the following shows:

(13) Yesterday's attempts to leave.

Here, the specifier is filled, so PRO cannot appear, yet the facts are the same as in (12). The implicit arguments hypothesis, modelled on (9), will say:

(14) for attempt, and similar nouns, the Agent controls (or is associated with) the subject of the embedded clause.

1 The difference between control and association may not be as great as the text here implies. Suppose that the INFL to takes the NP and VP as a single ' joint ' a rgument ; then a control s tructure will look like this:

(i) V [NPi to VPI]INFL (Xi)

When the subject is empty, X~ will be an unsatura ted predicate. The control of infinitives could then be construed as 'association' with the Xi a rgument of the INFL to.

P R O A N D S U B J E C T OF NP 303

The null hypothesis of implicit argument association receives some confirmation from the fact that again, whether the specifier is filled or not seems irrelevant to the facts of association between arguments, and furthermore, the association is indifferent as to whether the Agent is expressed or not, and if expressed, as to where it appears syntactically:

(15)a. Any attempt to leave. b. Their attempt to leave. c. Yesterday's attempt by them to leave.

Again, then, the implicit argument theory seems to be in the right direction, as it operates without reference to the syntactic expression of arguments. The examples in (15) each compactly exemplifies the great difficulty that any effort to conflate NP subjects and S subjects faces. In each example, we have a relation between two items, one the Agent of attempt, the other the PRO subject of the embedded S. The first item may be expressed or not, and may be in any appropriate position if expressed, so long as it is Agent; furthermore, the filling of other syntactic positions in the NP is irrelevant. The second, the subject of the embedded S, must not be expressed, the subject must be vacant, and it does not matter what theta role it involves. This strongly suggests that the former is an implicit argument, and the latter, a syntactic position.

3 . C O N D I T I O N B OF T H E B I N D I N G T H E O R Y IN NPs

In connection with condition B, there is again a certain amount of misleading evidence suggesting that there is a PRO position in NP.

Certain cases of disjoint reference in NPs could be cited to support the claim that the binding theory is 'seeing' a PRO in the specifier position, and thus favor the NP PRO view. For example, in the following, we have disjointness between John and him, which we might attribute to the disjointness of PRO (which John controls) and him:

(16) John took a PRO picture of him.

Of course, this case can be equally well treated under the implicit arguments view, if we let condition B 'see' the implicit arguments; we might leave the binding theory essentially as it is, and give the following treatment of implicit arguments:

(17) Animplicit argument c-commands X if the verb (or noun) of which it is an implicit argument c-commands X. If an implicit argument is coindexed with X and c-commands X, then it binds X.

In (17) we are giving an implicit argument a syntactic status like other


syntactic items, and we are identifying its syntactic position as the position of the verb or noun of which the implicit argument is an argument. In fact, (17) need not necessarily be restricted to implicit arguments; however, its effects for explicit (syntactically expressed) arguments will be redundant, as the binding theory will hold among expressed arguments in the usual way.

In (16) the implicit Maker argument of picture c-commands him and is in the same local domain as him, so disjointness between the two arguments of picture holds under principle B; since John is identified with the Maker argument (see (9)), John cannot be the same as him.

The correctness of the implicit arguments view is confirmed by the following:

(18) John took his picture. I

(Maker, Patient)

If his is understood as filling the Patient role of picture, then disjointness obtains, and otherwise not. This fact does not plausibly follow from any structural rule of disjointness, since the given structure in general allows coreference:

(19) Johni found hisi picture.

Rather, it follows from the fact that condition B holds among implicit arguments (they c-command each other by (17)), and the fact tlaat take specifies that its subject is associated with the Maker role of its object.

This account also explains why we have disjointness in the following:

(20) John took a picture of him.

since again the implicit Maker argument of picture, with which John is associated, c-commands and binds the pronoun, by (17). So (18) and (20) are ruled out for exactly the same reason; the only difference between (18) and (20) is in the manner of the syntactic realization of the expressed argument (specifier position in (18), object of picture in (20)), but this is not a relevant difference, as condition B will hold between the implicit arguments regardless.

A further argument for having condition B hold among argument slots derives from the behavior of his own. Coreference obtains between John and his own in the following (a) example, even if his own is understood as the Patient role (and so differs from his in (18)):

(21)a. John took his own picture. I

(Maker, Patient) b. John took a picture of himself.

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We may account for this by exempting his own from condition B. Here, although the Maker role c-commands and occurs in the same minimal domain as his own, disjointness is not assigned, since his own is not a pronoun, but an anaphor, of sorts. At least, it does not undergo B; it seems to undergo neither A nor B, so it is unclear what to call it. See Pusteiovsky and Williams (in preparation) for a discussion of the status of such anaphors. The (b) example is similar, with the reflexive exempt from condition B as well. But this account of the difference between (18) and (21) relies on condition B taking into account implicit arguments and their associations, for, as we have seen (in (19)), the structural relation between the matrix subject and the specifier of the embedded NP permits coreference in generai.

We find different, but symmetrically different, facts with verbs like submit x to and undergo, which trigger association to the Patient role of the embedded N, rather than the Maker or Agent role:

(22)a. John submitted himself to her scrutiny. b. *Johni submitted himself to hisi thorough scrutiny. c. John submitted himself to his own thorough scrutiny.

In (a) John is associated with the Patient role of scrutiny, and her with the Agent role. So disjointness is enforced in (b) by condition B, but not in (c), just as in (20) and (21). Here the associated roles are all switched, but the facts are otherwise the same. The verb submit entails association between its Actor role and the Patient role of its complement NP; the verb perform on the other hand entails association between its Actor role and the Actor role of its complement NP; hence the facts of disjointness in (23):

(23)a. John performed her autopsy. b. *John~ performed hisi autopsy. c. John performed his own autopsy.

In summary then, we have seen that condition B seems to operate with respect to implicit arguments, in the same way that it operates between expressed arguments; hence, PRO is not needed in NP, and in fact only helps with a small number of the relevant cases, those in which a given argument could be expressed in the specifier position, a conclusion similar to that reached at the end of section 2.

4 . C O N D I T I O N C OF T H E B I N D I N G T H E O R Y A N D P R O IN N P

As in the case of B, we can show that cases of C that apparently 'see' PRO in NP are actually 'seeing' implicit arguments that are not expressed.


Ross (1969) has argued for PRO in NP on the basis of examples like the following:

(24) The PRO realization that John was unpopular upset him.

John cannot be the 'realizer' in (24). According to the NP PRO story, this is because the realizer role is assigned to PRO, and C requires that John be disjoint from PRO.

In a theory without PRO in NP, the Realizer role in (24) will be implicit. That implicit role will c-command John, according to (17), and so condition C will assign disjointness between John and that role.

As before, it is possible to show that the implicit argument story covers the full range of relevant cases, while the PRO in NP story covers only a subset. So, for example, the PRO story given for (24) cannot explain the disjointness that holds between the Realizer role and John in the following:

(25) Yesterday's realization that John was a fool

since yesterday's precludes the appearance of PRO in specifier position. Furthermore, for a triadic noun, we find condition C effects for ALL

implicit arguments, and of course only one of these (it doesn't matter which one) could be a PRO:

(26) The promise that John would win. I

(Agent, Goal, Thing promised)

Here, John is disjoint from both the Agent and Goal roles, either one of which, but not both of which, could be PRO. The facts of disjointness can be seen in the oddity of both of the following:

(27)a. *The promise that John would win was made to him yesterday. b. *The promise that John would win was made by him yesterday.

The visibility of implicit arguments to condition C can be shown for implicit arguments of verbs, as well as nouns:

(28)a. Mary went to the doctor's office, and she promised that the doctor would not see her again until she was really sick.

b. Mary went to the doctor's office, and she promised (the doctor) that he would not see her again until she was really sick.

Unlike (b), (a) cannot mean that Mary made the promise to the doctor; rather, she must have made it to someone else. On our story, this is


because promise has an implicit Goal role which, in (a), c-commands the doctor, and so must be understood as noncoreferential with it. (In (b) on the other hand, the implicit Goal c-commands the pronoun he and condition C does not apply; hence disjointness is not required.) Clearly condition C must be able to 'see' the implicit Goal argument of promise in (a). PRO of course cannot play any role in explaining these facts, since the expression of the Goal of promise, were it expressed, would be in indirect object position, where PRO cannot appear.

By now the lesson is familiar: PRO is helpful with a quite arbitrary subset of the cases that must fall under condition C; the implicit arguments theory, which covers the full range of facts mentioned here, makes the role of PRO entirely redundant.

5. P R O IN NP AND BOUND PRONOUNS

Higginbotham (1980) argues (p. 690, footnote 11) from a supposed difference in the availability of the bound pronoun reading in (29a) and (29b):

(29)a. PRO devotion to his country is expected of every soldier. b. The queen's devotion to his country inspires every soldier.

that the latter lacks the bound pronoun reading, and hypothesizes that the reading will be available only when there is a PRO subject of the NP to bind the pronoun, assuming that the configurational relation between the pronoun and the quantified NP will not allow direct binding. In fact, I believe that (29b) does not lack the bound pronoun reading. Higgin- botham himself concedes that such examples become "fully acceptable on the bound interpretation, if the context is properly rigged" (p. 688, footnote 10).

Even if there is a difference between (29a) and (29b), Higginbotham's conclusion does not follow, and he has not presented any case against the position of this paper, namely, that implicit arguments of the head noun can serve as antecedents - in this case, for the bound pronoun. We could then draw the distinction between the two cases in this way: in (a), the implicit Actor argument of devotion binds the pronoun, since it c- commands it in the sense of (17), and is itself bound by the quantified object; in (b) the Actor argument is explicit (the Queen) and so cannot be bound by the quantified phrase.

In sum, then, either interpretation of Higginbotham's data is com- patible with the implicit argument theory laid out here.

308 EDWIN WILLIAMS

6. LIMITS ON C O N T R O L BY IMPLICIT A R G U M E N T S

In his important paper on implicit arguments, Roeper (1983) has offered the following evidence for an NP PRO, based on control of result clauses:

(30) The destruction of the city to impress the general.

The idea here is that there is a PRO subject of destruction and it controls the (subject of) the result clause. An alternative view is that there is no PRO subject of destruction, but that the result clause is directly controlled by the implicit but unexpressed argument of destruction. Here we use implicit argument in the sense used earlier in this paper. We will in fact reject both these analyses of (30), arguing that there is another mechanism 6perating in such clauses. It will be no surprise that the NP PRO view wilt be rejected, as it has been consistently rejected in this paper. It may however be a surprise that we are rejecting the pure implicit argument view, since we have already seen that implicit arguments are 'visible' to rules of sentence grammar, even for control (sections 1 and 2).

The cases cited by Roeper that favor the implicit argument view over the NP PRO view are cases like the following:

(31)a. The game was played nude. b. The ship was sunk to impress the general.

In these cases, the AP nude in (a) and the result clause in (b) appear to be controlled by the agent of the matrix verb, even though there could not be any possibility of a PRO controller in such examples, as there was in (30).

Williams (1974) gives an alternative account of result clause control which will allow us to dispense with the NP PRO analysis of (30) and (31a), and that account can be extended to (31b) as well. In that account, the matrix S itself is available as a controller of the result clause:

(32) [John went to New York]i [PROi to annoy Mary].

For (32), we might say that at least one of the readings is one in which it is the event itself of John's going to New York that will annoy Mary, not John directly. In fact, (32) seems ambiguous on this point. Let us call the kind of control just defined S-CONTROL (since it is the matrix S which controls the result clause).

If we extend S-control to N' control, we do not need to posit NP PRO, or implicit argument control, to account for (30). The result clause is


controlled by the N' sinking of the ship, in the sense that it is the sinking of the ship that will impress the general, not the sinker of the ship. The same remarks apply to (31b), where we may say that the result clause controller is the S the ship was sunk, in the sense that it is the fact that the ship is sunk that will impress the general.

In (31a), rather than saying that the adjective nude modifies the implicit agent of played we might say that it modifies the (overt) subject game, since one may call a game nude if it is played by nude people. This would explain why it is so odd to say,

(33) *The game was played mad at Bill. (cf. John played the game mad at Bill.)

since one cannot say, "The game was mad at Bill." Similarly the following examples show that the controller of the result clause in the passive cannot be the implicit agent:

(34)a. *The boat was sunk to become a hero. (Lasnik, pers comm.) b. *Mary was arrested to indict Bill. (Williams, 1974)

since it is nonsense to say that the boat's sinking could become a hero, or that an arrest could indict someone.

Examples (33) and (34) provide positive evidence against the view that the controller is always an implicit argument. Against them, we must consider the following cases of Roeper's, which suggest that the control- ter cannot always be S or N'.

(35)a. The boat was destroyed to collect the insurance. b. The destruction of the boat to collect the insurance. c. *The boat's destruction to impress the general. d. The destruction of the boat to impress the general.

Examples (a) and (b) would seem to refute S and N' control, since collect would seem to select a human subject; marginally, though, one can say that boat-destruction could collect insurance (as in, That will collect you some insurance) at least more readily than one can say that boat- destruction could become a hero.

The ungrammaticality of (35c), in contrast with the grammaticality of (35d), seems, moreover, to provide an argument for NP PRO, since it can be attributed to the fact that NP PRO cannot appear in the specifier of (35c), which is filled by the boat, whereas it can appear in (35d), where the determiner is free. If an overt antecedent (where PRO is counted as overt) is required for control of result clauses, then (35c and d) are accounted for. On the other hand, if implicit arguments are permitted to


be controllers of result clauses, then there is no account of the difference between these two cases, as the implicit Agent would seem to be equally available in both.

But there is an explanation of the difference between (35c) and (35d) under the N' control view, which makes use of neither a PRO in specifier position nor of an implicit Agent controller. Suppose the result clause is attached under NP, but not under N'. Then the two sentences in question will have the following structure:

(36)c. *[the boat's [destruction]N, to impress the general]. d. [the [destruction of the boat]N, to impress the general].

In (36c), the boat's destruction does not form a constituent, and so cannot serve as controller, if controllers must be constituents. In (36d), on the other hand destruction of the city is a constituent, namely N'. So if the constituent structure is as indicated, these are readily explained without appeal to NP PRO.

Roeper cites the following cases as further support for the control-by- implicit-argument view:

(37)a. *The boat sank to impress the king. b. The boat was sunk to impress the king.

His reasoning is that it is the availability of an implicit agent in (b), but not (a), which is responsible for the difference. We need not accept this conclusion if there is some account for the difference that does not involve an appeal to implicit arguments. We have already explained (37b) (in the discussion surrounding (31b)) without recourse to implicit arguments, so it remains to explain (37a).

It is tempting, but I think wrong in the end, to say that when an S is controller, the S must denote an event which involves an Agent. This would distinguish (37a) from (37b), since the event in the first does not involve an Agent, and this is still not the same as positing control by the agent.

However, a wider range of cases shows that Agent has nothing to do with the difference between these two examples or with control of results clauses in general, at least if by Agent we mean one of the verbal arguments (implicit or not). So, for example, we have the following, in which we could not sensibly say that is or green has an implicit agent argument (nor can grass be sensibly construed as the controller):

(38) Grass is green to promote photosynthesis. (Williams, 1974)

Rather, we must simply suppose that there is some purposeful agent


(evolution, God) under whose control is the circumstance 'grass is green'. This is quite different from saying that God or evolution is an Agent in the theta-theoretic sense.

As for (37a), we can render it sensible in the same way that (38) is sensible if we can imagine a circumstance under which 'the boat sank' is a circumstance under the control of a purposive agent, etc. Suppose that a playwright is rationalizing the design of his play by saying the following:

(39) The boat sank in order to impress the queen and move her to murder her husband by the end of act iii.

This does not mean that the playwright impresses the queen; rather the sinking of the boat impresses the queen.

Example (37a) is still not fully explained: why must such an exotic circumstance be dreamed up to render it sensible; that is, why can the purposeful agent not be an Agent of the sinking in the theta-theoretic sense? I think that this is because the use of the intransitive sink strongly implies that there is no personal theta-theoretic agen t - it implies that the boat was not sunk by anyone in particular, it just sank. So it will only be in some exotic circumstance that it just sank and someone sank it are not contradictory.

It seems that there may be viable accounts of Roeper's evidence that do not involve implicit arguments or NP PRO subjects, and in fact there

seems to be positive evidence against the implicit argument approach, and in favor of the S and N control approach. It remains to be explained though why the implicit arguments are not available for controllers in these examples, whereas they were available in examples considered earlier. What is the difference between the two kinds of example?

(40)a. the desire to leave (implicit argument is controller)

b. the destruction of the city to prove a point (implicit argument is not a controller; N' is)

The obvious difference is that where the implicit argument can control, the controlled clause is an argument (of desire in (a)), and where it cannot, the controlled clause is an adjunct. So implicit arguments can control arguments, but not adjuncts.

But why should this be? Suppose that adjuncts are always generated outside of VP, or at least outside of the first projection of V, as in Jackendoff (1977), while arguments (the subject, or 'external' argument aside) are always generated inside of the first projection. Suppose further, that implicit arguments are only 'visible' to rules that are applying strictly


within the first projection of V. That is, they are visible only to rules that relate the verb to its arguments, or that relate coarguments to each other. Then it will follow that implicit arguments will be 'visible' as antecedents only for control of complements, never for control of adjuncts.

One might further ask why implicit arguments should be visible only in the first projection of V, while explicit (syntactically realized) arguments are visible in all higher phrases. The answer might lie in the special status of the argument structure of predicates. The argument structure of a verb determines theta role assignment for the verb. Theta role assignment (again leaving aside the external argument) is restricted to the first projection of the verb. This is perhaps because the argument structure of the verb is strictly a property of the verb, and is not percolated or inherited by projections of the verb; if it were, it would be hard to explain why the arguments were confined to the first projection. If we further require that information about heads that is not X-bar projected is not accessible except in the smallest projection, a proposal in the spirit of the cycle of Williams (1974), then we simultaneously explain why arguments are confined to the smallest projection, and also why implicit arguments serve as antecedents only for arguments, not for adjuncts.

There is one systematic exception to the above remarks about the visibility of argument structures, but it is an exception that proves the point: the subject. The subject is not included in the first projection of the predicate, and yet it must be available for theta role assignment. As I have argued elsewhere, the subject argument is systematically assigned by a different mechanism (as the 'external' argument). But consistent with this is the fact that the subject participates in the implicit argument system we have outlined; the examples of Higginbotham's ((29) above) already illustrate this:

(41) Devotion to his country inspires every soldier.

Here, there must be an association between the Experiencer argument of inspires and the Actor of the external argument (devotion). What this illustrates is the close relation between theta role assignment and the visibility of implicit arguments; theta role assignment is restricted to the first projection of the predicate, plus the subject; the visibility of implicit arguments is restricted in exactly the same way.

The essential correctness of this approach is suggested by the following examples of Chomsky's (1982, p. 46):

(42)a. *The books were sold without PRO reading them. b. The books can be sold without PRO reading them.


He observes that an overt controller is needed (but absent) in the (a) example, but is apparently not needed in the (b) example; in the (b) example, the PRO is controlled by an implicit argument.

Why does can make the difference it does? Suppose can itself takes arguments. Suppose it takes a subject argument, which in (42b) is of course implicit: the subject argument is the entity whose abilities the sentence is about. Suppose further that certain 'adjunct' clauses are really complements to the modals - this idea is explored in Williams (1974), with particular reference to the pair m u s t . . , in order to. Under these suppositions, (42b) is no longer mysterious. The implicit subject argument of can is controlling a complement of can, and this coincides exactly with our expectations about the visibility of implicit arguments. In the (a) example on the other hand, there is still an implicit argument (the agent of sold) but the without-c lause is not a complement of sold, so the implicit argument remains invisible under our assumptions. This line of theory suggests that the notion 'adjunct' might be relative, not absolute - the without-c lause is an adjunct with respect to sold in both (42a) and (42b), but it is a complement to can in (42b). It may well be a complement to 'tense' or INFL in (42a), but if tense takes no subject argument, then there will be no implicit argument to serve as controller.

7. CONCLUSION

In the preceding sections, we have examined a number of roles that PRO in the specifier of an NP might play in relating the interior of the NP to its exterior, with respect to the principles of the binding theory, bound pronouns, and control. In each instance, positing PRO in NP helped with only an arbitrary subset of the cases. The implicit arguments view outlined here encompasses the full range of cases.

If these conclusions are correct, then PRO in NP is unnecessary. However, these conclusions in no way undermine the case for PRO in S; if anything they strengthen it.

There are some ways in which the association of implicit arguments, mentioned in (9) and illustrated in subsequent examples, is similar to control of PRO. For example, the antecedent for both association and control is often determined by the verb. But association and control are different in one striking and important way: association assigns antecedents to argument slots of a specified kind (Actor, Patient, etc.) no matter how or if the argument is realized in a syntactic position, whereas control assigns antecedents to syntactic positions (the subject of infinitives, gerunds, etc. . . ) no matter what kind of arguments are realized there.

3 1 4 E D W I N W I L L I A M S

A further difference between association and control follows from the one just mentioned. Since control is a relation between an antecedent and a specified position (the subject position of infinitives, gerunds, etc.), there can be only one instance of control per embedded clause, namely control of that specified position. But since association is a relation between an antecedent and an argument of an embedded complement, there may be as many associations per complement as there are arguments. And in fact, the following exhibits double associations:

(43) John gave Mary a kick.

John is associated with the Actor role of kick, and Mary is associated with the Patient role of kick. There is no analogue of this double association with control structures. Furthermore, the existence of double association cases is further evidence that PRO in NP can give only a partial account of the facts.

Implicit arguments are not the mysterious shadowy presences they are sometimes made out to be. They are really nothing more than the argument slots in the argument structure of predicates, and they must be visible to syntax for the purpose of theta-role assignment in any case, since theta role assignment is nothing more than the linking of an argument slot in the argument structure with a syntactic position. A 'weak' theta criterion, which does not require that every argument slot be so linked, is all that is needed to give implicit arguments, since these are nothing more than unlinked argument slots.

Because the theta roles must be available for syntax anyway for purposes of theta role assignment, no substantial part of the lexicalist hypothesis is given up by the implicit arguments theory outlined in this paper. The argument structure of the lexical item is a complex property of a lexical item that sentence grammar rules have access to. We have given a narrow characterization of the rules that have access to the argument structure: the rules whose domain of application is the first projection of the predicate (see section 7); this includes theta role assignment, and applications of the binding theory that have implicit arguments as antecedents.

The visibility of argument slots for the binding theory raises the possibility that the binding theory is strictly a relation among argument slots, and not among syntactic positions, even when the argument slots are linked to syntactic positions. This cannot be right, though, for a number of reasons. First, control of PRO in S is strictly a matter of position, not type of argument, as just mentioned. Second, when an argument is linked to a reflexive, or a pronoun, it behaves differently

PRO AND SUBJECT OF NP 315

with respect to the binding theory than when it is filled with something else; a binding theory that took account only of argument-slot-to- argument-slot relations would not take account ot this. Also, the binding theory in general is not restricted to argument-to-argument relations. A syntactically realized NP can serve as an antecedent for adjuncts as well as co-arguments.

(44) John left in order to win.

So it appears that the binding theory (including control and the rule for bound pronouns) holds equally for implicit and explicit arguments, but with the visibility restrictions on implicit antecedents that follow from the fact that the argument structure does not X-bar project when the arguments are implicit.

R E F E R E N C E S

Chomsky, N.: 1982, Some Concepts and Consequences of the Theory of Government and Binding, MIT Press, Cambridge.

Higginbotham, J.: 1980, 'Pronouns and Bound Variables', Linguistic Inquiry 11, 679-708. Jackendoff, R.: 1977, 3f Theory, MIT Press, Cambridge. Pustejovsky, J. and E. Williams: in preparation, 'Principle B'. Roeper, T.: 1983, 'Implicit Arguments', manuscript, University of Massachusetts. Roeper, T. and S. J. Keyser: 1984, 'On the Ergative and Middle Constructions in English',

Linguistic Inquiry 1~, 381--416. Ross, J. R.: 1969, 'On the Cyclic Nature of English Pronominalization', in D. Reidel and

S. Schane (eds.), Modern Studies in English, Prentice-Hall, New Jersey, pp. 187-200. Williams: 1974, 'Rule Ordering in Syntax', unpublished PhD disertation, MIT.

: 1982, 'The NP Cycle', Linguistic Inquiry 13, 277-295.

Received 20 December ]984 Revised 13 May 1985

Dept. of Linguistics South College University of Massachusetts Amherst, MA 01003 U.S.A.

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PRO and subject of NP