What can you do? Imperative mood in Semantic Theory
Rosja Mastop

Abstract:
A common assumption in linguistic semantics is, that sentences of all 
types share a common, truth conditional core. For non-declaratives this 
means that we must distinguish between a mood-operator and a 
propositional (truth-conditional) content. So, for instance, an 
imperative sentence is treated as commanding that some proposition be 
made true. In this dissertation it is argued that such an analysis is 
not reasonable.

First of all, it makes declarative sentences the prime carriers of 
meaning. This is a way to maintain compositionality (word meaning is 
determined by the contribution to truth conditions alone), but at the 
cost of creating an artificial divide between a semantics that accounts 
for the meaning-relations between declaratives (such as consistency, 
entailment, etc.) and a pragmatics that has to account for the 
meaning-relations between non-declaratives.

Second of all, the mood/content analysis of imperatives fails to 
explain some of the most striking features of such sentences: (i) the 
properties of their (optional) subjects and (ii) their temporal and 
aspectual orientation. Ad (i), by default imperatives do not have a 
subject, but when they do, it functions as a means to pointing out who 
is to comply with the given instructions. Thus the quantified subjects 
in the examples below are not part of the truth conditional contents.

(1) Somebody get a doctor. (is not: see to it that somebody gets a 
doctor.)
(2) Nobody make a move.   (is not: see to it that nobody makes a move.)

On the mood/content account, we cannot give a semantic analysis of the 
meanings of these sentences. This shortcoming is all the more striking 
when it is noted that many languages have first and third person 
imperatives. (One example, the Dutch ``laten wij/zij VP-inf'', is 
discussed in some detail.) Ad (ii), imperatives are future oriented. 
They do not contain stative VPs and, in general, they do not have a 
past tense form. However, Dutch has a ``plusquamperfect imperative'', 
expressing a reproach (a counterfactual instigation) and always 
directed at the addressee.

(3) Had (*jij/*hij) dan ook gewoon de trein genomen!
(4) Was (*jij/*hij) toch lekker gaan fietsen!

Again, these phenomena cannot be dealt with if the imperative is merely 
a mood-operator with pragmatic rules of use.

In contrast to the mood/content analysis, the dissertation defends a 
semantic account that is characterized by the following traits.

(1) It is an update semantics. Declarative sentences are viewed as cues 
to change one's state of information and imperative sentences are 
viewed as cues to change one's to do list. This allows us to adopt a 
one-level approach in which imperative meaning is not `derivative' or 
pragmatic.
Furthermore, by using a constructive update semantic model, we can give 
a straightforward solution to the problems of disjunctive commands and 
permissions, much discussed in the literature.

(2) It treats those ``cues'' as perspective-dependent. Imperative 
sentences are interpreted from a subjective (second person) 
perspective, which explains why in general they do not need an overt 
subject. The quantified and non-second person subjects are analyzed as 
perspective *shifters*, which explains why in English and Dutch they 
are typically used when it is not clear from the context who are the 
ones that are being instructed. The speech time is the default temporal 
perspective, but the plusquamperfective operator is analyzed as a 
shifting this perspective into the past, resulting in an irrealis 
context of interpretation. This explains why it is meaningful to issue 
a `command' from a past-tense point of view.

Taken together, these two traits---dynamic and perspectival---make for 
a semantic approach in which declaratives do no longer form a 
privileged sentence type. Instead, the variety of sentence types can be 
accounted for by characterizing the different aspects of a person's 
cognitive state and the different ways they can be altered.