5.3.1 The auxiliary as a dummy

The ungrammaticality of most of the sentences in (159) shows that the main verb cannot be used in this way. That (159c) is not ungrammatical does not indicate that it is an exception, however, as this has a different meaning to (158c). In (159c), the emphasised verb is used to question or contradict a previous statement in terms of the content of the verb itself. So, for example, if someone claimed to have seen something that was invisible to others, (159c) might be an appropriate response. Importantly, (159c) could not be used to contradict someone’s claim that they did not see something, i.e. contradicting the truth of their statement. The point is, then, that the auxiliary do is inserted into a sentence to do something that is impossible for a main verb to do and hence it has a purely syntactic role rather than a semantic one. For this reason it is often called the dummy auxiliary. Perhaps its main function is to support the tense morpheme when, for whatever reason, this cannot appear on the main verb and hence the phenomenon is also called do-support.

5.3.1 The auxiliary as a dummy

The bracketed part of the sentences on the left in (161) express the same predication relationships as those on the right and the only difference between the two is the expression of tense in the latter. Thus it looks as though the copula is used to support the tense morpheme when predication relationships are established between a subject and a non-verbal element. It is interesting that the verb be is used in this case, not the verb do as it is in cases of do-support. Even though both elements seem to contribute little to the interpretation of the sentence, it seems that their use is specialised to certain contexts: do for cases where the main verb fails to be able to support tense and be for cases where there is no verb present to support tense. I know of no explanation for this fact.

6.2.2 Do-insertion

6.2.4 Movement to tense and I

We already have an account for the behaviour of the main verb in the presence of the negative. The negative is a head that blocks the movement of the verb over it. If negation is situated below the I position, then the verb will not be able to move to support the inflection and hence do-support is necessary, as demonstrated in (53b). This will not affect the process of auxiliary insertion however, as this does not involve movement. Yet, an inserted auxiliary bears both tense and agreement and so it seems to be inserted into tense and moved to I, suggesting that the position of the negation is lower than the tensed element, contradicting (49b) where negation is above the non-finite tense. It seems then that negation must be below a finite tense, but above the verb.

7.3.5 Subject questions

It seems that for some reason, to which we return shortly, main verbs cannot move to C. So when a wh-element moves to the specifier of CP and it requires some element in the C position to agree with, the dummy auxiliary is used and hence we get do-insertion. However, when the subject is the focus of the question, there is no do-insertion indicating that nothing has to move to C. If this is a general condition then it suggests that no element moves from I to C in subject questions and hence that (67c) is not correct. Opinions differ as to the correctness of (67a) or (b), but obviously both are problematic for the straightforward analysis of interrogatives.