Basic English Syntax with Exercises

PRO

8.2 Raising and Control

In reality then, the subject is not ‘missing’, it has just moved. By the same conditions, we cannot treat the independent missing subject as the result of movement: it bears a Θ-role different from its antecedent and so they do not represent a single argument, but two different ones. Moreover, at D-structure these two arguments must also be in different positions as different Θ-roles are assigned to different positions at D-structure. Hence we conclude that this kind of missing subject is present at D-structure. As we see in (51), this is not true of the other ‘missing’ subject. Because this element has many properties in common with a pronoun, i.e. it bears an independent Θ-role but can be referentially dependent on something else, it is often referred to as PRO.

8.2.2 Control

Let us now turn to the other non-finite clause with an apparently missing subject, in which there is in fact a phonologically empty pronoun. There are a number of interesting points to be made about this element. The first is that although it is obviously a DP, it has a much more limited distribution than normal DPs. The other matters of interest concerning the empty pronoun PRO are the limitations on its referential properties, as it does not appear to behave like other pronouns in this respect. We will consider these points separately.

8.2.2 Control

Note that there is nothing semantically wrong with these sentences. As PRO is a pronoun that refers to some other element in the sentence, the meaning of the sentences in (67), were they grammatical, would be perfectly understandable:

8.2.2 Control

Why is it that PRO cannot appear in these positions? One relevant observation is that these positions are those to which Case is assigned. The non-finite subject positions, in which PRO is allowed, seem to be Caseless as overt DPs cannot appear there and so presumably they violate the Case Filter:

8.2.2 Control

If PRO must avoid Case positions, we predict that we should not be able to go in the subject position of the non-finite complement of a exceptional verb, as this is a position assigned Case by the light verb of the exceptional verb. This expectation is indeed fulfilled:

8.2.2 Control

Similarly, PRO will not be able to appear with a for complementiser, which we have argued assigns Case to the subject position of the non-finite clause that it introduces:

8.2.2 Control

So it seems that PRO cannot appear in Case positions and is therefore in complementary distribution with overt DPs, which of course must sit in Case positions.

8.2.2 Control

However, this conclusion is problematic both conceptually and empirically. On conceptual grounds, it is odd to say the least that there should be a principle stating that all DPs must have Case and then to find out that there is one DP that not only does this not apply to, but exactly the opposite holds of it and it cannot have Case. The empirical issue is that the assumption does not account completely for the distribution of PRO as there are places which are not Case marked, and so could not support an overt DP, but in which PRO cannot appear either. One such place is the subject position of the non-finite complement clause of a raising verb or a passive verb:

8.2.2 Control

One possible solution to both these problems would be to claim that PRO doesn’t avoid Case positions per se, but has to sit in special Case positions which up to now have been assumed not to be Case-marked, but in fact might be assigned a special Case, applicable only for PRO. Chomsky and Lasnik (1989) proposed that PRO must sit in special Case marked positions. They argue that the subjects of certain non-finite clauses are not Caseless but that what they term ‘Null Case’ is assigned to them. Only PRO can bear Null Case and Null Case is the only Case that PRO can bear. Thus PRO will not be able to sit where overt DPs go as these will be Case marked with something other than Null Case. Moreover no overt DP can sit in a position in which it would be assigned Null Case as this is not ‘strong’ enough to satisfy the Case Filter. The good thing about this assumption is that it predicts complementary distribution between overt DPs and PRO but does not force us to assume that PRO can occupy any position in which we cannot find an overt DP. From this perspective, then, PRO cannot sit in a position to which no Case is assigned, as in (73).

8.2.2 Control

So far, I have remained uncommitted about the status of the clause that contains PRO: is it a CP or is it an IP? Under both assumptions that PRO cannot sit in Case positions or that it can only sit in Null Case positions we have to ensure that the place where it can be found is not assigned a full Case from an element outside the clause. We have seen that as PRO cannot be the subject of an exceptional clause it must be assumed that this is not possible. One way to ensure that nothing else can assign Case to the place occupied by PRO is to assume that it is protected by a CP. Recall that a governor can govern up to a CP, but not through it as CP acts as a barrier to government. For this reason then, we will assume that all clauses containing a PRO subject are CPs and not IPs.

8.2.2 Control

Turning to the referential properties of PRO we find that this is quite complex. To see how PRO behaves, we should first consider how other pronouns behave in terms of reference. There are two types of referential pronouns which behave differently with respect to each other. Compare the following:

8.2.2 Control

What kind of a pronoun is PRO: an anaphor or a pronominal? Interestingly, this is not such a straightforward question to answer as PRO demonstrates properties of both pronominals and anaphors and a number of properties that are unique to itself. One can find in the literature claims that PRO is a pronominal, an anaphor or even both! One observation is that PRO more than often must have an antecedent, a property that it shares with anaphors. Thus, in the following PRO must be taken as referentially dependent on the subject of the main clause and cannot be taken as referring to someone not mentioned:

8.2.2 Control

In other contexts, however PRO can lack an antecedent altogether. In these cases, it gets what is called arbitrary reference, a kind of generic reference similar to that of the pronoun one:

8.2.2 Control

While this is similar to the behaviour of a pronominal, it is not entirely equivalent. For one thing when a pronominal has no antecedent it still has a specific referent determined by the discourse conditions (i.e. who or what is the topic of the conversation or who or what is being indicated as the referent in non-linguistic ways such as pointing, etc.). Moreover, pronominals are free to lack antecedents in general whereas PRO can only lack an antecedent under specific circumstances. Basically, PRO can lack an antecedent, and therefore have arbitrary reference when the sentence that PRO is the subject of is itself a subject or when it is the complement of certain predicates:

8.2.2 Control

However, even describing the conditions under which PRO may have arbitrary reference is a complex business, let alone explaining why the language works like this. Thus we will not delve too deeply into this issue. One point of interest is the fact that in those instances where PRO may have arbitrary reference it seems that it has more referential freedom in general in that it is possible for it to have an antecedent, and therefore a more specific reference, and this antecedent may be in positions which are not normally accessible for pronouns to take their reference from. For example, consider the following:

8.2.2 Control

There are a range of possible ways to interpret this sentence depending on who is taken as the antecedent of PRO. The arbitrary reading is possible with the meaning that if anyone were to leave this would make things difficult for you. On the other hand, the sentence might mean that I am the one who could leave, and my leaving would make things difficult for you. Finally, it could mean that you are the person considering leaving and if this happens you will experience difficulties. All these cases involve conditions which are not possible for PRO in other contexts. In the first case, PRO has no antecedent, as already discussed. In the second the referent stands three clauses above the clause of which PRO is the subject and PRO typically has to have its antecedent in the next clause above it. Finally in the third possibility the antecedent is not in a structurally superior position and so it does not even count as a binder. Due to these observations, it has been claimed that in these circumstances PRO is free to refer to any element, as long as the conditions for that element are also respected, e.g. PRO would not be able to refer to a pronominal in a lower position in its own clause as this would give the pronominal a binder within its binding domain, which is not allowed for the pronominal.

8.2.2 Control

Turning to those cases where PRO must have an antecedent, we find further distinctions:

8.2.2 Control

In (81a) PRO has to be taken as coreferential with the object him and cannot refer to the subject. In contrast (81b) has PRO referring to the subject, not to the object. This is again very different from the referential conditions facing other pronouns, which although they either must or cannot take an antecedent within the binding domain, depending on whether they are an anaphor or a pronominal, are free to take any possible antecedent within these confines:

8.2.2 Control

While there may be more or less ‘natural’ readings for these sentences, which are determined by pragmatic considerations, it is possible to think of contexts in which the pronouns could refer to either the subject or the object in each case: perhaps the tailor in (82a) is modelling a suit for the customer and wants to show the customer a certain effect that can best be seen by looking in the mirror, for example. However there are no contexts in which we could make the subject a possible antecedent for PRO in (81a) or the object in (81b) as the referential possibilities in this case are grammatically and not pragmatically determined. We call this property of PRO having to take its reference from one place or another control. Specifically, (81a) involves object control while (81b) involves subject control. It seems that what determines the control properties of PRO is the governing verbs: ask is an object control verb while promise is a subject control verb. Obviously when there is no object, subject control is the only possibility. When there is an object, overwhelmingly verbs tend to be object control and only a very small number of verbs behave like promise and have an object and yet control from the subject.

8.3 The Gerund

However, such gerunds are standardly assumed to have PRO subjects and hence the subject position is not empty and we can account for why the determiner is impossible. In such gerunds we might suppose that the ing morpheme is added to the structure quite high, perhaps above the tense element. If we further assume that it is a non-finite tense which is responsible for assigning the Null Case borne by PRO we can account for why it is possible to have a PRO subject in a gerund.