In this paper I draw attention to a number of problems that afflict norm accounts of assertion, i.e. accounts that explain what assertion is, and typically how speakers understand what assertion is, by appeal to a norm of assertion. I argue that the disagreements in the literature over norm selection undermines such an account of understanding. I also argue that the treatment of intuitions as evidence in the literature undermines much of the connection to empirical evidence. I further argue that (...) appeals made to conversational patterns do not require the existence of any norms at all. (shrink)
This is the first part of a two-part article on semantic compositionality, that is, the principle that the meaning of a complex expression is determined by the meanings of its parts and the way they are put together. Here we provide a brief historical background, a formal framework for syntax and semantics, precise definitions, and a survey of variants of compositionality. Stronger and weaker forms are distinguished, as well as generalized forms that cover extra-linguistic context dependence as well as linguistic (...) context dependence. In the second article, we survey arguments for and arguments against the claim that natural languages are compositional, and consider some problem cases. It will be referred to as Part II. (shrink)
An assertion is a speech act in which something is claimed to hold, e.g. that there are inﬁnitely many prime numbers, or, with respect to some time t, that there is a traﬃc congestion on Brooklyn Bridge at t, or, of some person x with respect to some time t, that x has a tooth ache at t. The concept of assertion has often occupied a central place in the philosophy of language, since it is often thought that making assertions (...) is the use of language most crucial to linguistic meaning, and since assertions are the natural expressions of cognitive attitudes, and hence of importance for theories of knowledge and belief. (shrink)
Can there be rules of language which serve both to determine meaning and to guide speakers in ordinary linguistic usage, i.e., in the production of speech acts? We argue that the answer is no. We take the guiding function of rules to be the function of serving as reasons for actions, and the question of guidance is then considered within the framework of practical reasoning. It turns out that those rules that can serve as reasons for linguistic utterances cannot be (...) considered as normative or meaning determining. Acceptance of such a rule is simply equivalent to a belief about meaning, and does not even presuppose that meaning is determined by rules. Rules that can determine meaning, on the other hand, i.e., rules that can be regarded as constitutive of meaning, are not capable of guiding speakers in the ordinary performance of speech acts. (shrink)
This is the second part of a two-part article on compositionality, i.e. the principle that the meaning of a complex expression is determined by the meanings of its parts and the way they are put together. In the first, Pagin and Westerståhl (2010), we provide a general historical background, a formal framework, definitions, and a survey of variants of compositionality. It will be referred to as Part I. Here we discuss arguments for and against the claim that natural languages have (...) a compositional semantics. We also discuss some problem cases, including belief reports, quotation, idioms, and ambiguity. (shrink)
This paper contains a discussion of how the concept of compositionality is to be extended from context invariant to context dependent meaning, and of how the compositionality of natural language might conflict with context dependence. Several new distinctions are needed, including a distinction between a weaker (e-) and a stronger (ec-) concept of compositionality for context dependent meaning. The relations between the various notions are investigated. A claim by Jerry Fodor that there is a general conflict between context dependence and (...) compositionality is considered. There is in fact a possible conflict betwee ec-compositionality and context dependence, but not of the kind Fodor suggests. It turns on the presence of so-called unarticulated constituents, in John Perry’s sense. Because of this phenomenon, on some semantic accounts there might be a variation in the meaning of a complex expression between contexts without any corresponding variation in any of the syntactic parts of that complex. The conflict can be resolved in several ways. One way is to make the unarticulated context dependence explicit only in the meta-language, which makes it into an unarticulated constituent account. A recent argument by Jason Stanley against such accounts is discussed. According to Stanley, certain readings of English sentences involving binding of contextual variables, are unavailable in these theories. After considering a reply to Stanley by François Recanati, I present an outline of a fully compositional theory, of the unarticulated constituent variety, which does deliver these readings. Concluding remarks on, inter alia, the semantics/pragmatics distinction. (shrink)
Donald Davidson is, arguably, the most important philosopher of mind and language in recent decades. His articulation of the position he called "anomalous monism" and his ideas for unifying the general theory of linguistic meaning with semantics for natural language both set new agendas in the field. _Interpreting Davidson_ collects original essays on his work by some of his leading contemporaries, with Davidson himself contributing a reply to each and an original paper of his own.
Suppose we have an idea of what counts as communication, more precisely as a communicative event. Then we have the further task of dividing communicative events into successful and unsuccessful. Part of this task is to find a basis for this evaluation, i.e. appropriate properties of speaker and hearer. It is argued that success should be evaluated in terms of a relation between thought contents of speaker and hearer. This view is labelled ‘classical’, since it is justifiably attributable to both (...) Locke and Frege (section 2). Most of the paper is devoted to discussing competing contemporary views, such as behaviorist/pragmatist views (section 4), requirements of knowledge (section 5), of reliability (section 6) and that success should be defined in terms of public language semantics rather than in terms of thought content (section 7). (shrink)
Saul Kripke's thesis that ordinary proper names are rigid designators is supported by widely shared intuitions about the occurrence of names in ordinary modal contexts. By those intuitions names are scopeless with respect to the modal expressions. That is, sentences in a pair like (a) Aristotle might have been fond of dogs, (b) Concerning Aristotle, it is true that he might have been fond of dogs will have the same truth value. The same does not in general hold for definite (...) descriptions. If one, like Kripke, accounts for this difference by means of the intensions of the names and the descriptions, the conclusion is that names do not in general have the same intension as any normal, identifying description. However, this difference can be accounted for alternatively by appeal to the semantics of the modal expressions. On the account we suggest, dubbed 'relational modality', simple singular terms, like proper names, contribute to modal contexts simply by their actual world reference, not by their descriptive content. That account turns out to be fully equivalent with the rigidity account when it comes to truth of modal and non-modal sentence (with respect to the actual world), and hence supports the same basic intuitions. Here we present the relational modality account and compare it with others, in particular Kripke's own. (shrink)
Starting from the familiar observation that no straightforward treatment of pure quotation can be compositional in the standard (homomorphism) sense, we introduce general compositionality, which can be described as compositionality that takes linguistic context into account. A formal notion of linguistic context type is developed, allowing the context type of a complex expression to be distinct from those of its constituents. We formulate natural conditions under which an ordinary meaning assignment can be non-trivially extended to one that is sensitive to (...) context types and satisfies general compositionality. As our main example we work out a Fregean treatment of pure quotation, but we also indicate that the method applies to other kinds of context, e.g. intensional contexts. (shrink)
Peter Pagin Is the principle of semantic compositionality compatible with the principle of semantic holism? The question is of interest, since both principles have a lot that speaks for them, and since they do seem to be in conflict. The view that natural languages have compositional structure is almost unavoidable, since linguistic communication by means of new combinations of words would be virtually incomprehensible otherwise. And holism too seems generally plausible, since the meaning of an expression is directly connected with (...) the way that expression interacts with other. (shrink)
Natural kind terms have exercised philosophical fancy ever since Kripke, in Naming and Necessity, claimed them to be rigid designators. He there drew attention to the peculiar, name-like behavior of a family of prima facie loosely related general terms of ordinary English: terms such as ‘water’, ‘tiger’, ‘heat’, and ‘red’. Just as for ordinary proper names, Kripke argued that such terms cannot be synonymous with any of the definite descriptions ordinary speakers associate with them. Rather, the name-like behavior of these (...) so-called natural kind terms is to be explained, just as in in the case of proper names, by the doctrine of rigid designation. And as a consequence of thus extending the notion of rigid designation to general terms, he famously endorsed the claim that so-called ‘theoretical identifications’, i.e. statements like (1) Water is H2O, are necessary, if true. (shrink)
Ordinary semantic compositionality (meaning of whole determined from meanings of parts plus composition) can serve to explain how a hearer manages to assign an appropriate meaning to a new sentence. But it does not serve to explain how the speaker manages to find an appropriate sentence for expressing a new thought. For this we would need a principle of inverse compositionality, by which the expression of a complex content is determined by the expressions of it parts and the mode of (...) composition. But this presupposes that contents have constituent structure, and this cannot be taken for granted. However, it can be proved that if a certain principle of substitutivity is valid for a particular language, then the meanings expressed by its sentences can justifiably be treated as structured. In its simplest form, this principle says that if in a complex expression a constituent is replaced by another constituent with a different meaning, the new complex has a meaning different from the original. This principle is again inversely related to the normal compositional principle of substitutivity. The combination of ordinary and inverse compositionality is here called 'strong compositionality'. The proof is carried out in the algebraic framework developed by Wilfrid Hodges and Dag Westerståhl. (shrink)
The standard argument against ordered tuples as propositions is that it is arbitrary what truth-conditions they should have. In this paper we generalize that argument. Firstly, we require that propositions have truth-conditions intrinsically. Secondly, we require strongly equivalent truth-conditions to be identical. Thirdly, we provide a formal framework, taken from Graph Theory, to characterize structure and structured objects in general. The argument in a nutshell is this: structured objects are too fine-grained to be identical to truth-conditions. Without identity, there is (...) no privileged mapping from structured objects to truth-conditions, and hence structured objects do not have truth-conditions intrinsically. Therefore, propositions are not structured objects. (shrink)
Saul Kripke’s thesis that ordinary proper names are rigid designators is supported by widely shared intuitions about the occurrence of names in ordinary modal contexts. By those intuitions names are scopeless with respect to the modal expressions. That is, sentences in a pair like (a) Aristotle might have been fond of dogs (b) Concerning Aristotle, it is true that he might have been fond of dogs will have the same truth value. The same does not in general hold for definite (...) descriptions. If we, like Kripke, account for this difference by means of the intensions of names and descriptions, we have to conclude that names do not in general have the same intension as any normal, identifying description. However, the difference in scope behavior between names and description can be accounted for alternatively by appeal to the semantics of the modal expressions. On the account we suggest, dubbed ‘relational modality’, simple singular terms, like proper names, contribute to modal contexts simply by their actual world reference, not by their (standard) intension. The relational modality account turns out to be fully equivalent with the rigidity account when it comes to truth of modal and non-modal sentences (with respect to the actual world), and hence supports the same basic intuitions. Given an alternative definition of consequence for relational modality, and a restriction to models with reflexive accessibility relations and non-empty world-bound domains, relational modality also turns out to be model theoretically equivalent with rigidity semantics with respect to logical consequence. Here we introduce the semantics, give the truth definition for relational modality models, and prove the equivalence results. (shrink)
In this paper the informativeness account of assertion (Pagin in Assertion. Oxford University Press, Oxford, 2011) is extended to account for inference. I characterize the conclusion of an inference as asserted conditionally on the assertion of the premises. This gives a notion of conditional assertion (distinct from the standard notion related to the affirmation of conditionals). Validity and logical validity of an inference is characterized in terms of the application of method that preserves informativeness, and contrasted with consequence and logical (...) consequence, that is defined in terms of truth preservation. The proposed account is compared with that of Prawitz (Logica yearbook 2008, pp. 175-192. College Publications, London, 2009). (shrink)
Naive speakers find some logical contradictions acceptable, specifically borderline contradictions involving vague predicates such as Joe is and isn’t tall. In a recent paper, Cobreros et al. (J Philos Logic, 2012) suggest a pragmatic account of the acceptability of borderline contradictions. We show, however, that the pragmatic account predicts the wrong truth conditions for some examples with disjunction. As a remedy, we propose a semantic analysis instead. The analysis is close to a variant of fuzzy logic, but conjunction and disjunction (...) are interpreted as intensional operators. (shrink)
Suppose you are stranded on an island and you want to get over to the nearby mainland. Your only option is to swim. But is the other shore close enough? If you embark and it isn’t, you drown. So you prefer to know before taking off. Happily, you are well equipped. You have not only a yardstick, but also a theodolite for measuring angles, and a good knowledge of trigonometry. You then determine the distance to the other shore by means (...) of triangulation. You fix two points, A and B, on your own shore, and identify a third point, C, in sight on the opposite shore. You then measure the distance between A and B with your yardstick, and the two angles ABC and CAB with your theodolite. With this information you can calculate the distances AC and BC to the other shore. (shrink)
In 1956 J. L. Austin presented his famous distinction between performative and constative.1 Roughly, whereas in a constative utterance you report an already obtaining state of affairs—you say something—in a performative utterance you create something new: you do something.2 Paradigm examples of performatives were utterances by means of which actions such as baptizing, congratulating and greeting are performed.
The term ‘meaning holism’ has been used for a number of more or less closely interrelated ideas. According to one common view, meaning holism is the thesis that what a linguistic expression means depends on its relations to many or all other expressions within the same totality. Sometimes these relations are called ‘conceptual’ or ‘inferential’. A related idea is that what an expression means depends, mutually, on the meaning of the other expressions in the totality, or alternatively on some semantic (...) property of this totality itself. The totality in question may be the language to which the expressions belong, or a theory formulation in that language. (shrink)
In this paper I shall be concerned with the relation between a particular account of linguistic meaning and the property of compositionality in natural language.1 The account, proposed by Donald Davidson, is that based on considerations about radical interpretation. I shall argue that there is a fundamental conflict between, on the one hand, the view that the meaning of expressions of natural languages is determined purely according to canons of radical interpretation, and, on the other hand, the view that natural (...) languages exhibit compositional structure. I shall also argue that if there is such a conflict, this speaks against the proposed account. (shrink)
This article focuses on the relevance of computational complexity for cognition. The syntactic items may be expressions that are surface strings. But in general, strings are syntactically ambiguous in that they can be generated in more than one way from atomic expressions and operations. The semantic function must take disambiguated items as arguments. When expressions are ambiguous, expressions cannot be the arguments. Instead, it is common to take the arguments to be terms, whose surface syntax reflects the derivation of the (...) string. The semantic function differs in one other important respect from an arithmetic function, since it maps entities between domains, from a syntactic to an ontic or conceptual domain of meanings. Compositionality helps to explain the rate of success in linguistic communication when the sentence used or the content communicated is new. (shrink)
The principle of semantic compositionality, as Jerry Fodor and Ernie Lepore have emphasized, imposes constraints on theories of meaning that it is hard to meet with psychological or epistemic accounts. Here, I argue that this general tendency is exemplified in Michael Dummett's account of meaning. On that account, the so-called manifestability requirement has the effect that the speaker who understands a sentence s must be able to tell whether or not s satisfies central semantic conditions. This requirement is not met (...) by truth-conditional accounts of meaning. On Dummett's view, it is met by a proof conditional account: understanding amounts to knowledge of what counts as a proof of a sentence. A speaker is supposed always to be capable of deciding whether or not a given object is a proof of a given sentence she understands. This requirement comes into conflict with compositionality. If meaning is compositionally determined, then all you need for understanding a sentence is what you get from combining your understanding of the parts according to the mode of composition. But that knowledge is not always sufficient for recognizing any proof at all of a given sentence. Dummett's proof-theoretic argument to the contrary is mistaken. (shrink)
This paper concerns the phenomenon of pragmatic enrichment, and has a proposal for predicting the occurrence of such enrichments. The idea is that an enrichment of an expressed content c occurs as a means of strengthening the coherence between c and a salient given content c’ of the context, whether c’ is given in discourse, as sentence parts, or through perception. After enrichment, a stronger coherence relation is instantiated than before enrichment. An idea of a strength scale of types of (...) coherence relations is proposed and applied. (shrink)
This article is concerned with the principle of compositionality, i.e. the principle that the meaning of a complex expression is a function of the meanings of its parts and its mode of composition. After a brief historical background, a formal algebraic framework for syntax and semantics is presented. In this framework, both syntactic operations and semantic functions are partial. Using 20 the framework, the basic idea of compositionality is given a precise statement, and several variants, both weaker and stronger, as (...) well as related properties, are distinguished. Several arguments for compositionality are discussed, and the standard arguments are found inconclusive. Also, several arguments against compositionality, and for the claim that it is a trivial property, are discussed, 25 and are found to be flawed. Finally, a number of real or apparent problems for compositionality are considered, and some solutions are proposed. (shrink)
This paper is an attack on the Dummett-Prawitz view that the principle of bivalence has a crucial double significance, metaphysical and meaning theoretical. On the one hand it is said that holding bivalence valid is what characterizes a realistic view, i.e. a view in metaphysics, and on the other hand it is said that there are meaning theoretical arguments against its acceptability. I argue that these two aspects are incompatible. If the failure of validity of bivalence depends on properties of (...) linguistic meaning, then there are no metaphysical consequences to be drawn. The case for this view is straightforward as long as we are discussing a language different from our own. But it seems that the distinction between failure because of meaning and failure because of reality cannot be applied to our own language, simply because our own language is just what we use to represent reality. I argue that this impression is illusory. In order to draw a conclusion about reality, meaning must be connected with truth in a non-trivial way, and precisely this cannot be done in the language for which the meaning theory itself is correct. (shrink)
According to the knowledge account of assertion, an assertion that p is correct just in case the speaker knows that p. This is so because of a norm that governs assertion and uniquely characterizes it. Recent opposition to the knowledge account accepts that assertion is governed by a norm, but proposes alternatives to the knowledge norm. In this paper I focus on some difficulties for normative accounts of assertion.
It is often assumed that there is a close connection between Quine's criticism of the analytic/synthetic distinction, in 'Two dogmas of empiricism' and onwards, and his thesis of the indeterminacy of translation, in Word and Object and onwards. Often, the claim that the distinction is unsound (in some way or other) is taken to follow from the indeterminacy thesis, and sometimes the indeterminacy thesis is supported by such a claim. However, a careful scrutiny of the indeterminacy thesis as stated by (...) Quine, and the varieties of the analytic/synthetic distinction, reveals that the two claims are mutually independent. Neither does the claim that the distinction is unsound follow from the indeterminacy thesis, nor that thesis from unsoundness claim, under any of the common interpretations of the analytic/synthetic distinction. (shrink)
The ﬁrst case is usually referred to as omissive and the second as commissive. What is traditionally perceived as paradoxical is that although such statements may well be true, asserting them is clearly absurd. An account of Moore’s Paradox is an explanation of the absurdity. In the last twenty years, there has also been a focus on the incoherence of judging or believing such propositions.
Are sensation ascriptions descriptive, even in the first person present tense? Do sensation terms refer to, denote, sensations, so that truth and falsity of sensation ascriptions depend on the properties of the denoted sensations? That is, do sensation terms have a denotational semantics? As I understand it, this is denied by Wittgenstein. Wittgenstein rejects the idea of a denotational semantics for public language sensation terms, such as‘pain’. He also rejects the idea that speakers can recognizesensations. I think these views are (...) mistaken.In this paper I shall present the following: first, my own basic views on how public language sensation terms relate to sensations ; second, to what extent these views are inconsistent with some of Wittgenstein's main tenets about sensations and sensation language, as set out in Philosophical Investigations##243–315, and what I take to be Wittgenstein's main arguments, in the same text, for those tenets ; third, why I think that those arguments are inconclusive ; and fourth, what I see as the best arguments for my own views. Sections 3 and 5 are concerned with the bearing of the private language argument on these matters. (shrink)
The idea of higher-order vagueness is usually associated with conceptions of vagueness that focus on the existence of borderline cases. What sense can be made of it within a conception of vagueness that focuses on tolerance instead? A proposal is offered here. It involves understanding ‘definitely’ not as a sentence operator but as a predicate modifier, and more precisely as an intensifier, that is, an operator that shifts the predicate extension along a scale. This idea is combined with the author’s (...) earlier approach to the semantics of vague expressions, which builds on the idea of a central gap associated with a predicate. The central gap approach is generalized to handle arbitrarily many iterations of ‘definitely’. (shrink)
On what seems to be the best interpretation, what Quine calls 'the problem of synonymy' in Two Dogmas is the problem of approximating the extension of our pretheoretic concept of synonymy by clear and respectable means. Quine thereby identified a problem which he himself did not think had any solution, and so far he has not been proven wrong. Some difficulties for providing a solution are discussed in this paper.
The main purpose of this paper is to propose and defend anew definition of synonymy. Roughly (and slightly misleadingly), theidea is that two expressions are synonymous iff intersubstitutions insentences preserve the degree of doxastic revisability. In Section 1 Iargue that Quine''s attacks on analyticity leave room for such adefinition. The definition is presented in Section 2, and Section 3elaborates on the concept of revisability. The definition is defendedin Sections 4 and 5. It is, inter alia, shown that the definition hasdesired (...) formal properties. In Sections 6 and 7 I briefly comment on,first, the relation of the definition to Quine''s later ideas about (stimulus)synonymy, and, second, its relation to a general, interlinguistic, conceptof meaning. (shrink)
Treating the principle of charity as a non-empirical, foundational principle leads to insoluble problems of justification. I suggest instead treating semantic properties realistically, and semantic terms as theoretical terms. This allows us to apply ordinary scientific reasoning in meta-semantics. In particular, we can appeal to widespread verbal agreement as an empirical phenomenon, and we can make use of probabilistic reasoning as well as appeal to theoretical simplicity for reaching the conclusion that there is a high rate of agreement in belief (...) between speakers who have a high rate of verbal agreement. Although this does not by itself imply that the beliefs agreed upon are generally true, it does imply that any single speaker who is party to such a verbal agreement is justified in taking the other speakers to have mostly true beliefs. She is so justified because of the fact that it is incoherent to take her own beliefs not to be mostly true. Indirectly, this justifies a version of the principle of charity as an empirically correct principle. (shrink)
If proofs are nothing more than truth makers, then there is no force in the standard argument against classical logic (there is no guarantee that there is either a proof forA or a proof fornot A). The standard intuitionistic conception of a mathematical proof is stronger: there are epistemic constraints on proofs. But the idea that proofs must be recognizable as such by us, with our actual capacities, is incompatible with the standard intuitionistic explanations of the meanings of the logical (...) constants. Proofs are to be recognizable in principle, not necessarily in practice, as shown in section 1. Section 2 considers unknowable propositions of the kind involved in Fitch''s paradox:p and it will never be known thatp. It is argued that the intuitionist faces a dilemma: give up strongly entrenched common sense intuitions about such unknowable propositions, or give up verificationism. The third section considers one attempt to save intuitionism while partly giving up verificationism: keep the idea that a proposition is true iff there is a proof (verification) of it, and reject the idea that proofs must be recognizable in principle. It is argued that this move will have the effect that some standard reasons against classical semantics will be effective also against intuitionism. This is the case with Dummett''s meaning theoretical argument. At the same time the basic reason for regarding proofs as more than mere truth makers is lost. (shrink)
In his paper ‘Why assertion may yet be social’ (Pegan 2009), Philip Pegan directs two main criticisms against my earlier paper ‘Is assertion social?’ (Pagin 2004). I argued that what I called “social theories”, are inadequate, and I suggested a method for generating counterexamples to them: types of utterance which are not assertions by intuitive standards, but which are assertion by the standards of those theories. Pegan’s first criticism is that I haven’t given an acceptable characterization of the class of (...) social theories. His second criticism is that I have overlooked some alternatives, and that there are social theories that are not affected by my argument. In section 1 I discuss the first, and in section 2 the second. (shrink)
A new formalism for predicate logic is introduced, with a non-standard method of binding variables, which allows a compositional formalization of certain anaphoric constructions, including donkey sentences and cross-sentential anaphora. A proof system in natural deduction format is provided, and the formalism is compared with other accounts of this type of anaphora, in particular Dynamic Predicate Logic.
However, if Wittgenstein’s so called rule-following considerations are correct, then this reason for believing in the validity of (C), is mistaken. The conclusion of those considerations is that we must reject the idea that rules are things which determine possible cases of application before those cases are actually encountered and decided by speakers. If this is right, then there is no rule which determines the meanings of new sentences, i.e. before those sentences have actually been used. Therefore, it might seem (...) that (C) is not valid for natural languages. (shrink)
In his recent paper ‘Analyticity: An Unfinished Business in Possible-World Semantics’ (Rabinowicz 2006), Wlodek Rabinowicz takes on the task of providing a satisfactory definition of analyticity in the framework of possible-worlds semantics. As usual, what Wlodek proposes is technically well-motivated and very elegant. Moreover, his proposal does deliver an interesting analytic/synthetic distinction when applied to sentences with natural kind terms. However, the longer we thought and talked about it, the more questions we had, questions of both philosophical and technical nature. (...) Hence the idea of this little paper – for how better to honor a philosopher than by trying very hard to criticize him? After quickly running over some background in possible worlds semantics and setting out Wlodek's proposal against that background, we shall bring up and discuss our questions in sections 3 – 5. In the final section, we shall also make a stab at a different solution to the problem, making use of our own earlier idea of relational modality. (shrink)
The paper discusses the question whether T-theories explain how it is possible to understand new sentences, or learn an infinite language, as Davidson claimed. I argue against some commentators that for explanatory power we need not require that T-theories are implicitly known or mirror cognitive structures. I note contra Davidson that the recursive nature of T-theories is not sufficient for explanatory power, since humans can work out only what is computationally tractable, and recursiveness by itself allows for intractable computational complexity. (...) I finally consider the complexity of T-theories, transformed into term rewriting systems, and find that the complexity of such systems is indeed tractable. Therefore Davidson's claim stands, even though a further condition had to be met. (shrink)