Evening lectures

ESSLLI 2015 will feature four public evening lectures. We are happy to announce the following invited speakers:

Tuesday, August 4, 2015 - 19:00

Hans Kamp

Auditori Poblenou

Ever since Montague’s seminal work in the late 60’s and early 70’s Formal Semantics has worked something like this: (i) Specify a syntax for a fragment of some language; (ii) specify a class of models: (iii) define, by a recursion that follows the syntax, for each expression E of the fragment and each model M from the model class the semantic value of E in M. In particular, such a definition must assign to each sentence S and model M a truth value of S in M, or else a proposition that gets a truth value at each of the relevant different ‘indices’ of M.

As I have just stated it, this schema is an oversimplification. The semantic values of many NL expressions depend on various aspects of context. Therefore ‘semantic value’ must be treated, minimally, as a function with three arguments: (a) expression, (b) model and (c) context.

The ‘Formal Semantics Approach’ (FSA) has been implemented in various ways, e.g. by defining the semantic values directly from the syntactic structure or indirectly, via an intervening semantic representation or logical form. But common to all those implementations is a user-neutral stance: Semantic values (of expressions in models, given contexts) are treated as properties of the language as autonomous system. (Competent users of the language are those that behave in conformity with the properties it has qua autonomous system.)

We will contrast this perspective with that of the Communication-Theoretic Approach (CTA), in which language is studied as a device for communicating information between language users. According to CTA the semantics of the language resides in the coding principles that allow speakers to express their thoughts and the decoding principles that enable their audiences to recover those thoughts from their words. Context is as indispensable in CTA as it is in FSA, but now contexts have to be treated as part of the mental states of language users.

I argue that some phenomena are better handled within a CTA framework than with the traditional methods of FSA. The examples I will discuss have to do with how speakers choose the noun phrases they need to refer to the things they want to talk about and how their addressees interpret those noun phrases. The central part of the talk will be the sketch of a CTA account of these phenomena. After that I will look at a few questions about the relationship between FSA and CTA. In particular:

1. What are the prospects for a rigorous formalization of CTA?

2. Can FSA be regarded as a kind of approximation to CTA?

3. Can FSA be embedded in some way within CTA, and under what conditions?

[Note from local organization: slides available here.]

Thursday, August 6, 2015 - 19:00

Chris Barker

Auditori Poblenou

Sometimes the dog wags the tail:

(1) Ann gave Bill cookies. == gave bill cookies ann

And sometimes the tail wags the dog:

(2) Ann gave everyone cookies. == everyone (λx. gave x cookies ann)

In (1), the functor gave applies to its arguments in the normal way. In (2), the argument everyone somehow manages to take control over the entire sentence that contains it, quantifying over all the people Ann may have given cookies, and substituting those individuals into the original argument position one by one. In other words, an embedded expression can take scope over a larger expression that contains it. Scope-taking is a robust and pervasive feature of English and many other natural languages. The usual account of scope-taking in linguistics is a quasi-logical rule known as Quantifier Raising, which licenses an inference from the left-hand side of (2) to the right-hand side. But Quantifier Raising is never studied as an integral part of a formal logic. In the tradition of Lambek and of Moortgat, I will present a substructural logic that characterizes scope-taking. As an example of one of the insights that can come from taking a formal logical approach, Quantifier Raising on its own does not guarantee any limit on the length of a derivation; in contrast, the logic here is decidable, leading to an effective parsing strategy. I will also explain how the logic makes explicit use of continuations, a concept from the theory of computer programming languages: roughly, the tail is the scope-taking expression, and the rest of the dog is its continuation. So what is the logic of scope? Here is my answer: reasoning about scope-taking is reasoning about continuations.

[Note from local organization: slides available here.]

Tuesday, August 11, 2015 - 19:00

Raquel Fernández

Auditori Poblenou

Spontaneous conversation requires a substantial amount of linguistic, cognitive, and social skills. Uncovering how these skills manifest themselves in language is of crucial importance for understanding human communication and for building computer systems that successfully interact with people using natural language. In this talk I will review several examples illustrating conversational phenomena of interest (the nails of linguistic interaction) and discuss how they can be explored using different methodologies -- the many hammers of the modern LLI researcher.

[Note from local organization: slides available here.]

Thursday, August 13, 2015 - 19:00

Albert Atserias

Auditori Poblenou

In certain areas of the mathematical sciences, and we want to think of the theory of computation as
such, measuring progress is not easy. What makes a mathematical statement good or more
interesting than another? What makes a proof of a theorem good or better than another? It is often
said that you recognize a good theorem when you see it, but that's hardly a useful definition. We
want to claim that some of the greatest contributions of the theory of computation provide precise
answers to this sort of question. Among the many incarnations that this claim can take, in this talk I
focus on the role that the theory of computational complexity can play to guide the search for better
theorems in our quest for a more understandable world.