Do so anaphora is a fairly widely used in English, but has received relatively little treatment in the literature (especially when compared with verb phrase ellipsis). There are, how- ever, two aspects of this anaphor that have gained prominence: i) its use as a test for constituency within the verb phrase, and ii) the semantic restriction it places on its antecedent. Though these two properties have been the most prominent, their analyses have not been uncontroversial. In this dissertation, I investigate these properties and give them a more complete analysis. The first part of the dissertation is devoted to a discussion of the the use of do so as a test for constituency in the verb phrase, and the second part is devoted to understanding the semantic restriction that do so places on its antecedent.

The behavior of do so anaphora has been used to argue both hierarchical structure (Lakoff and Ross 1976) and flat structure within the verb phrase (Culicover and Jackendoff 2005). In chapter 2, however, I argue that do so does not have any bearing on the debate about the internal structure of the verb phrase. The arguments put forth by these authors are predicated on do so being a surface anaphor in terms of Hankamer and Sag (1976). Instead I argue that do so is in fact a deep anaphor and that its purported surface anaphor properties fall out from independent semantic and pragmatic properties of the anaphor. As a deep anaphor, do so does not replace any structure in the verb phrase, but rather forms a verb phrase in its own right from the beginning of the derivation. Therefore, the use of do so to argue for or against hierarchical structure in the verb phrase has been misguided.

I approach the semantic restriction that do so places on its antecedent from two angles. In chapter 3, I review the previous analyses of this restriction, and test their claims against a corpus of over 1000 naturally occurring examples extracted from the American National Corpus. None of the previous analyses are supported by the data, and I present a novel analysis that utilize three semantic parameters (agentivity, aktionsart, stativity) to predict which antecedents are possible with do so. One striking property of the counterexamples found in the corpus is that they instantiate particular syntactic structures. The majority of them contain do so in a nonfinite form (usually in the infinitive), and in others, the antecedent is contained in a relative clause modifying the subject of do so. In chapter 4, I present experimental evidence that shows that these two syntactic environments lessen the effects of the restriction that do so normally places on its antecedent. I attribute this amelioration of the semantic restriction to the unavailability of verb phrase ellipsis in these syntactic environments. The analysis falls out from the nonmonotonic interaction of the two restrictions: the syntactic restrictions on ellipsis force the use do so to the detriment of the semantic restriction that do so normally places on its antecedent. I then situate this amelioration effect into the typology of coercion effects in general and argue that do so displays a novel type of coercion: subtractive coercion.