|AUTHOR: Portner, Paul H.
SERIES TITLE: Oxford Surveys in Semantics and Pragmatics
PUBLISHER: Oxford University Press
Zhiguo Xie, Department of Linguistics, Cornell University
Paul Portner's book is intended as a systematic survey of contemporary semantic
theories of sentential modality, most of which were developed within the
framework of possible world semantics. The book has five chapters, with Chapter
4 containing the biggest bulk of theoretical reviews and analyses. A
self-contained monograph, it does not assume much familiarity on the reader's
part with modal logic or any major theory of linguistic modality, so that those
who have just started exploring modality will find the book very accessible and
helpful. On the other hand, experts will find the book an excellent resource to
turn to when they want to have a quick brush-up on one theory of modality or
another. An authoritative figure on linguistic modality, Portner takes an
unimposing position when presenting his own ideas (where applicable). Overall,
the book is a great pleasure to read.
Chapter 1 contains a very brief introduction to modality and delineates the
range of topics to be discussed in the upcoming four chapters. Of the three
categories of modal forms -- sentential modality, sub-sentential modality and
discourse modality, the discussion in the book is limited to the first category,
with the other two left to another venue.
Chapter 2 provides a brief introduction to modal logic, which is an
indispensible tool for the formal analysis of modality. Portner's discussion of
modal logic is divided into two interrelated parts: a more
philosophically-oriented one (§2.2) and a more semantically-oriented (§2.3). In
the first part, such essential concepts as frame, model, valuation function,
accessibility relation and validity are defined and applied to a simple yet
well-designed modal game. In logic, the (in)validity of a sentence is due to its
logic properties and devoid of specific content. Modal logic was designed to
capture the logical properties of modal expressions. However, for this purpose
the frame has to be specified in greater details: W is a set of possible
worlds and R is defined in terms of concepts like knowledge and rules. Portner
defines modal frames in the model-theoretic framework he has concisely outlined
and shows how modal logic leads to a better understanding of modality. Towards
the end of the first part, Portner presents some axioms and systems of
philosophical modal logic, as well as their relationship to frames and validity.
In the second part of the chapter, Portner summarizes a generalization
underlying most current formal theories of modal expressions in natural
language: the Simple Modal Logic Hypothesis. The hypothesis says that the
meaning of every modal expression can be expressed in terms of whether it is a
necessity or a possibility modal and in terms of its accessibility relation. It
is hard to define a concept of weak necessity so as to capture some people's
intuition that there ought to be more options than just necessity and
possibility, because the set of possible worlds is standardly assumed to be
infinite. A given accessibility relation may have different sub-types; and a
given modal may be compatible with many different accessibility relations
(perhaps indefinitely many). The most common varieties of modality include
epistemic, deontic, ability, bouletic, teleological, and historical. Portner
spells out the definitions of the accessibility relations corresponding to some
of these modal types. The Simple Modal Logic Hypothesis does not make reference
to the identity of the speaker and the time at which the modal sentence is used;
that is, it fails to capture the indexicality of modals.
Chapter 3 aims to review major linguistic theories of modality: Angelika
Kratzer's 'standard' ordering semantics of modality, dynamic logic theories of
modality, as well as cognitive and functional theories of modality. Compared to
the 'Modal Logic for Linguistics' as outlined in Chapter 2, in Kratzer's
theories pragmatics plays a more significant role in the interpretation of modal
expressions. In place of the accessibility relation, Kratzer (1977) uses the
concept of conversational backgrounds, which is a function from worlds to sets
of propositions. A modal sentence is interpreted with respect to a context and a
conversational background. Necessity and possibility modals can be interpreted
in terms of entailment and compatibility, respectively. The different readings
of a certain modal are determined by the choice of conversational background,
and not all kinds of conversational backgrounds can be employed to interpret
each modal. The theory put forward in Kratzer (1977), however, does not make
reference to comparison and ordering between different possible worlds. This
leads to a number of empirical challenges.
A conversational background can be used to define a partial ordering on a set of
possible worlds. In Kratzer (1981)'s revised analysis of modality, the
interpretation of a modal sentence is doubly relative to two conversational
backgrounds: the modal base and the ordering source. Ordering semantics can
capture graded modality, comparative modality, the Samaritan paradox and
Chisholm's paradox, as well as subtle differences in modal meanings. However,
Kratzer's version of ordering semantics appears to fall short of complex
expressions of probability and possibility, and the so-called weak necessity
modals like 'ought'. To handle this problem, von Fintel and Iatridou (2006)
propose that the meaning of 'ought' involves two distinct ordering sources.
The second part of the chapter concerns the dynamic semantics of modality. The
dynamic view of meaning takes the meaning of a sentence as an information change
potential. Modal operators can be defined in the dynamic logic system. A
sentence of the form 'diamond β' checks whether β is compatible with an
information state. If the information update is not empty, then the information
state is left unchanged. If it is not, it leads to a defective information
state. A sentence of the form 'box φ' checks whether the current information
state already contains the information in φ. Dynamic logic is useful for
tackling non-epistemic modals and such modality-related topics as the logic of
expectation often embodied in sentences containing the words 'normally' and
Despite the fact that functional and cognitive approaches to modality often do
not aim to provide a 'serious' semantic theory, Portner devotes the last section
of the chapter to the two frameworks. In the cognitive semantic approach to
modality, it has been argued that deontic modal meanings are metaphorical
extensions of the force dynamical concepts, and the same analysis presumably can
be extended to the domain of epistemic modality. However, crucially the view
cannot explain the non-actuality of modality, a core property inspiring possible
world semantic analysis of modality in the first place. Neither can it provide
analysis of the nature of force dynamics of authority, desire, evidence, etc.,
which relate to hypothetical situations. In addition, Portner shows that the
cognitive-functional criticism against formal semantic analyses of modality
either does not hold or simply arises from misunderstanding. Furthermore,
functional and cognitive approaches to (inter)subjectivity of modality do not
have as much advantage as they have traditionally claimed over formal approaches.
Chapter 4 is the most essential part of the book, in which Portner provides
reviews, remarks and analyses of a number of phenomena which fall into the broad
category of sentential modality. In Portner's classification, there are three
primary categories of sentential modality: epistemic, priority (including
deontic, bouletic and teleological) and dynamic (including volitional and
quantificational). Epistemic modals have often been taken not to fit into
standard theories of modal semantics. First, epistemic modals do not contribute
to the ordinary, truth conditional semantics of sentences containing them, but
affect the type of speech acts performed by the sentences in which they occur.
Second, the truth or falsity of an epistemic modality shows a certain degree of
relativity to such factors as who evaluates it.
Portner starts his review of the semantics of epistemic modality in §4.2 by
examining Papafragou (2006), who identifies two empirical puzzles to argue that
epistemic modals lack an ordinary truth-conditional semantics. One has to do
with the limitations on the embedding of epistemic modals; the other with
patterns of assent, dissent and questioning towards epistemic modal sentences.
Portner shows that the non-truth-conditional analysis is not as strong as
Papafragou and others had thought. Dynamic logic does not come to their rescue,
as it does not explain all the important facts which motivate the
non-truth-conditional perspective. In contrast, probabilistic semantics analyzes
epistemic modals as involving performativity, in that it identifies three types
of speech act which are presumably relevant to epistemic modals. Portner shows
that it does not help Papafragou in any direct way.
The nature of subjectivity plays an essential role in the analysis of epistemic
modals. Papafragou's claim, that subjectivity arises when the speaker is the
sole member of the relevant group that an epistemic modal quantifies over, does
not make any reference to the dichotomy of modal base and ordering source.
Portner suggests two distinct notions of subjectivity, each based on one of the
two types of conversational backgrounds. In addition, epistemic modals are not
evidentials, which typically have been analyzed as non-truth-conditional.
Analyses of performativity of epistemic modals fall into two types: those that
claim an epistemic modal sentence expresses a reduced level of commitment and
those that claim an epistemic modal sentence brings up or 'proffers' a
possibility. Portner posits that a sentence of the form 'might S' both asserts
the modal proposition and adds to the common propositional space the unmodalized
In epistemic modal contexts, relativism is the dependency of the semantic
meaning of a modal sentence on the context of evaluation. There are two main
arguments offered in the literature for the relativist view. One concerns
embedding an epistemic modal under a verb like 'say'. Stephenson's (2007)
proposal, that the identity of a 'judge' affects the meaning of several kinds of
sentences, is helpful in dismissing this argument. The second major argument,
the presence of an eavesdropper, can receive alternative explanation as well. In
Portner's view, either the epistemic modal or the associated non-modal
proposition can be judged for truth or falsity, and certain considerations of
relevance can determine which one to use in a particular case.
Portner's review and discussion of issues in the semantics of priority modals
concern the argument structure of priority modals and the connection between
priority modals and imperatives. Some deontic modals are control predicates and
some others are raising predicates. The subject sometimes plays a different role
in the semantics of priority modals than in the semantics of epistemic modals.
Utterance of priority modal sentences can put the addressee under an obligation,
and in this sense priority modals are performative. Based on Lewis's discussion
of performativity of deontic expressions, Portner (2007), among others, develops
the idea that a priority modal sentence expresses a proposition within the
possible world semantics, and at the same time adds the proposition (property)
it expresses to the To-Do-List of the addressee. Imperatives and priority modals
are thus closely related.
The line between volitional and quantificational modals is murky. Assuming 'can'
also can function as a quantificational modal, the subject of a volitional modal
in English, which is a control predicate, is invariably an agent or a cause. As
for volitional modality, Portner's discussion focuses on ability modals. Common
to the major available analyses of the semantics of ability modality is the idea
of combining existential quantification, which corresponds to the idea that the
agent chooses some action, with universal quantification, which corresponds to
the idea that the action guarantees an outcome.
Perfective sentences containing ability modals and certain priority modals
entail that the event described in the sentences actually occurred, giving rise
to actuality entailment. Bhatt (1998) argues that 'able to' in a perfective
context is an implicative predicate, and that in imperfective context a higher
Gen(eric) operator removes the actuality entailment. Hacquard (2006) criticizes
Bhatt's analysis and derives the actuality entailment of ability modals in
perfective contexts through the interaction of event semantics and modal
semantics. With Hacquard, the perfective aspect undergoes movement to a higher
position binding the event argument of the verb. Through event identification
across worlds, the event associated with the verb exists in both the accessible
worlds and the actual world, hence actuality entailment arises. Portner points
out that Hacquard's analysis cannot rule out actuality entailment for the
imperfective cases. Rather, he identifies the actuality entailment as a special
case of performativity.
Quantificational modals function as adverbs of quantification and modals
simultaneously. They quantify over counting situations (both actual and possible
ones). The semantics of quantificational 'will' is identical to that of
'always', except for the accessibility relation between situations and worlds in
In Chapter 5 Portner undertakes the task of examining the relations between
modality and several other intensional categories including temporality,
conditionals and evidentiality. Modal sentences sometimes contain tense. In some
cases the tense is grammatically marked but does not contribute to semantic
interpretation (e.g. 'should'), while in some other cases it is grammatically
present and semantically real (e.g. 'could'). The scopal relation between an
epistemic modal and the perfect shows a certain degree of flexibility, which
leads to an epistemic/metaphysical ambiguity. In such cases there are two
sources of 'pastness', one from the temporal perspective and the other from the
temporal orientation. How to shift the temporal perspective and temporal
orientation for a theory of past interpretation of modals is an open issue. The
many varieties of modals add to the problem.
As for the future interpretation of modal sentences, some analyses hold that
tense is not involved in the future readings, while other analyses agree that
futurity is due to an interaction between the modal meaning and some general
principle (aspectual semantics, modal type, etc). With regard to 'will', one
school of views hold that 'will' is not a future tense but just a modal, whereas
others argue it is never a modal and has a purely temporal meaning. Both
proposals have their own problems.
Some simple present tense sentences express genericity or a future situation,
both being a kind of modality. A past tense can express modality in terms of
genericity or unreality (counterfactuality). The progressive expresses modality
with a unique combination of accessibility relation and temporal meaning. The
perfect expresses some modal meaning as well, though the analyses available in
the literature differ considerably with regard to what kind of modality it
expresses. Towards the end of the book, Portner points out some major issues
concerning the relationship between modality on one hand and conditionals, mood,
as well as evidentiality on the other hand. He does not delve into the details
of these topics, leaving them to a later venue.
Why is this book an important piece of work? First, as far as I know it provides
the first comprehensive, up-do-date survey of a wide range of modals and related
phenomena. All types of sentential modality (epistemic, priority and dynamic)
receive the extensive discussion they deserve, which integrates across such
topics as tense, aspect, subjectivity, and performativity. The wide of range of
issues addressed in the book alone makes it a great reference book for those who
work on modality.
Theoretical breadth and depth are another merit easily witnessed in the book.
Breadth is easily seen in Chapters 2-3, where Portner explains modal logic and
major theories of modality. His unbiased review covers not only formal semantic
approaches to modality, but also the modal logic, dynamic, functional and
cognitive frameworks of modality. Portner provides clear reviews of the many
proposals that logicians, philosophers of language and semanticists have made on
various aspects of modality over the past forty years or so. He demonstrates
great expertise in summarizing complex arguments and presenting them to the
reader in a less technical manner. The assessment and comparison he gives of the
different ideas are precise and accessible. When the mechanisms and frameworks
he examines and/or employs may be difficult for beginners to understand, he
works out the details to a considerable extent. For example, on page 68 he uses
an illustrative figure to go through the abstract definition for 'necessity
modal' in ordering semantics.
And, even more importantly, Portner keeps his critical eyes wide open through
the book. He makes another valuable contribution to the project of investigation
into modality through pointing out various issues with analyses put forward in
the literature. Here is just one example that illustrates this merit. In §5.1.2.
Portner suggests that Kissine's (2008) explanation that 'will' is never a modal
does not rule out another equally possible approach and thus what Kissine shows
does not guarantee his conclusion. There are a lot of other such examples in the
book. By doing so, Portner threshes out many open issues in the semantics of
modality that await further research. So the book is a valuable resource
especially for beginning students of modality to identify potential topics that
they can work on.
I am not suggesting that the book is impeccable. It contains a number of typos
(for example, on pages 43, 42, 44, 50, 86, 87, 94, 95, 125, 200, 205, 207, 208,
211, 261). In addition, Portner cites Pancheva's (published) work on pages
245-46, but he does not include the reference in the bibliography. Though these
are just small points, some readers of the book may find it more or less
Content-wise, I find the discussion on a few topics covered in the book somewhat
confusing and not as easy to follow as the rest of the book. For example, on
pages 210-211, Portner tries to argue that Hacquard's aspect-based analysis of
ability modality cannot explain the absence of actuality entailment when an
ability modal appears alongside the imperfective. However, his argument involves
an explicit qualification 'if the actual world is a normal world'. I am not sure
if the actuality entailment under such a qualification is still the same
actuality entailment that Hacquard is after. On a separate topic, Portner uses
modals embedding under conditionals as an argument for the claim that deontic
modals have both a truth conditional contribution and a performative
contribution. I suspect that the same evidence can be used to support the
exactly opposite claim, e.g. one along the lines of Schwager (2006). In
addition, the definition for temporal orientation he offers on page 228 makes
reference to the temporal relationship between the speech time and the event
time. If I understand it correctly, the definition is at odds with what
Condoravdi (2002) uses, on which Portner claims to base his definition.
Following Portner's definition, the counterfactual reading for 'non-root modal +
have' as classified by Condoravdi does not have the future orientation, but
stays open with respect to temporal orientation.
Bhatt, Rajesh. 1998. Covert Modality in Non-Finite Contexts. PhD Dissertation.
University of Pennsylvania.
Condoravdi, Cleo. 2002. Temporal Interpretation of Modals: Modals for the
Present and for the Past. In David Beaver et al (eds.). The Construction of
Meaning: 59-88. Stanford, CA: CSLI Publications.
von Fintel, Kai & Sabine, Iatridou. 2006. How to Say Ought in Foreign: The
Composition of Weak Necessity Modals. Paper presented at the Fall 2006 Workshop
in Philosophy and Linguistics at the University of Michigan.
Hacquard, Valentine. 2006. Aspects of Modality. PhD Dissertation. MIT.
Kissine, Mikhail. 2008. Why 'Will' Is Not a Modal. Natural Language Semantics
Kratzer, Angelika. 1977. What 'Must' and 'Can' Must and Can Mean. Linguistics
and Philosophy 1: 337-355.
Kratzer, Angelika. 1981. The Notional Category of Modality. in H. J. Eikmeyer,
and H. Rieser (eds.). Words, Worlds, and Contexts: 38-74. Berlin: de Gruyter.
Papafragou, Anna. 2006. Epistemic Modality and Truth Conditions. Lingua 116:
Portner, Paul. 2007. Imperatives and Modals. Natural Language Semantics 15: 351-383.
Schwager, M. 2006. Conditionalized Imperatives. SALT 16: 241-258.
Stephenson, Tamina. 2007. Towards a Theory of Subjective Meaning. PhD
ABOUT THE REVIEWER
| ABOUT THE REVIEWER:
Zhiguo Xie is a PhD candidate in linguistics at Cornell University. His
broad research interest is in crosslinguistic semantic variation and
universality. He has worked on modality, questions, NPIs and verb duplication.