September 08, 2010, 6-7:30 PM in 234 Moses Hall

Daniel Rothschild (Oxford)

Dynamics of the Connectives

We note that there are certain uses of both ‘and’ and ‘or’ that cannot be explained on their normal truth-table meanings (even when supplemented with sophisticated pragmatic tools).  These include examples such as the following: 1) Laurent shows up and a fight will break out. = If Laurent shows up then a fight will break out. 2) John is away or his car would be here. = John is away.  If he were not away, then his car would be here. To explain these uses we give an analysis of what we call the `dynamic’ effects of connectives, which arise even when they have their normal truth-table meaning.  We argue that the special uses in 1) and 2) are instances where the connectives have just their dynamic effects without having their truth-table meaning. (This is joint work with Nathan Klinedinst.)

October 20, 2010, 6-7:30 PM in 234 Moses Hall

Dilip Ninan (Arché Center, St. Andrews)

Self-Location and Other-Location

The centred worlds approach to de se thought has been much discussed in recent years. Despite this, the question of how to treat de re thought from within this framework has received little attention. I show how the basic centred worlds strategy to the de se can be usefully extended to the de re, and argue that the resulting theory – the “sequenced worlds” account – avoids problems facing alternative approaches.

November 10, 2010, 6-7:30 PM in 234 Moses Hall

Jeremy Heis (Logic and Philosophy of Science, UC Irvine)

Ernst Cassirer on ‘Substance-concepts’ and ‘Function-concepts’

Ernst Cassirer’s book Substanzbegriff und Funktionsbegriff (1910) – despite the recognition it has recently received from philosophers of mathematics and science – is a difficult book for contemporary readers to understand.  Its topic, the theory of concept formation, engages with debates and authors that are largely unknown today.  And its “historical” style violates the philosophical standards of clarity that characterize analytic philosophy.  Cassirer, for instance, never says explicitly what he means by “substance-concept” and “function-concept.” 

In this paper, I answer three questions: Why did Cassirer choose to focus on the topic of concept formation?  What did Cassirer mean in contrasting “substance-concepts” and “function-concepts”? and How does Cassirer’s polemic against traditional theories of concept formation lead to the distinctive theories in the philosophies of mathematics and science that he defends later in the book?  I argue that Cassirer’s contrast between substance-concepts and function-concepts includes four kinds of interrelated contrasts  – contrasts that touch on issues in logic, metaphysics, epistemology, and the theory of objectivity.  I argue that the book presents a progressively unfolding and intricate argument that begins with epistemological problems in the theory of concept formation and culminates in a defense of mathematical structuralism, a new theory of the a priori, and a “structural” account of scientific theory change.

December 01, 2010, 6-7:30 PM in 234 Moses Hall

John Mumma (Stanford University)

A quasi-formal account of Euclid’s diagrammatic proof method

I present a quasi-formal account of the proof method in Euclid’s Elements, based on recent formalizations of Euclid’s diagrammatic arguments ([Avigad et al, 2010], , [Mumma, 2010]). The account is quasi-formal, rather than simply formal, in that it gives geometric content an irreduciable role in Euclid’s proofs. It is quasi-formal, rather than simply informal, in that this role is subject to formal constraints. Inferences which are based on geometric concepts occur within a precisely defined formal framework. I first motivate and explicate the account by contrasting it with Jody Azzouni’s view on the relation of informal proofs to formal proof systems. I then illustrate how the formal framework of the account constrains informal inferences by considering proposition 20 of book I of the Elements, which asserts the triangle inequality. Though arguably obvious from a geometric perspective, the proposition cannot be inferred directly within the framework. One must prove it as Euclid does.

J. Avigad, E. Dean, and J. Mumma. A formal system for euclid’s Elements. Review of Symbolic Logic, 2:700–768, 2009.

March 09, 2011, 6-7:30 PM in 234 Moses Hall

Peter Ludlow (Northwestern University)

Linguistic Judgments

In this talk, I make four claims:

1. Linguistic Phenomena, Data, and Theory Need to be Distinguished: I argue that much of linguistic practice turns on the role of what I will call linguistic phenomena. To a first approximation, linguistic phenomena are facts about the acceptability and interpretation of linguistic objects. I argue that these facts or phenomena are explained by the theory of grammar. Linguistic data, on the other hand, provide evidence for the linguistic phenomena. As we will see, there are many potential sources of data, some (especially linguistic intuitions) much more controversial than others.

2. Linguistic Intuitions are Linguistic Judgments: Among other sources of data, generative linguists often use so-called linguistic intuitions as evidence when constructing our theory of grammar. Many linguists and philosophers take these intuitions to be “Cartesian” in the sense that they are the inner voice of competence. Contrarily, taking a leaf from Williamson (2004) I ague that linguistic intuitions are not “the voice of competence,” but are merely defeasible judgments about linguistic phenomena or facts.

3. Linguistic Judgments are Reliable (enough): Thinking of linguistic intuitions as judgments can help us avoid being traumatized by the possibility of error in our linguistic data gathering (error is simply something that we have to live with). It can also help us to see that some informants may be better judges than others. I make the case that linguistic judgments are useful, economical, and on the whole reliable sources of data.

4. Linguistic Judgment is Scientific Experimentation: I argue that when linguists isolate particular judgments to make the case for their theories they are involved in a fairly standard form of scientific investigation. That is, they are setting up controlled, replicable experiments in which they and other experimenters are judging whether a sentence is acceptable and/or what its interpretation might be. This leads to the question of which judges are good judges and why. I point out that this is similar to the question of what makes for a good experimenter in any science and leads us as well into what is sometimes called “the experimenter’s regress.” I’ll offer that we can break the regress by identifying good experimenters using easy cases where judgments converge.

March 30, 2011, 6-7:30 PM in 234 Moses Hall

Richard Scheines (Carnegie Mellon University)

Conceptual Problems for Causal Inference

Although a great deal of progress has been made in the last two decades on formally representing causal systems, axiomatizing the relations between causation and probabilistic independence, and on developing algorithms that learn about causal structure from data, there are still many serious conceptual problems with what are now often referred to as graphical causal models. In this talk I will briefly review the progress that has been made, but then focus on the challenges that remain unsolved.

April 27, 2011, 6-7:30 PM in 234 Moses Hall

Helen Longino (Stanford University)

A pluralist stance towards the sciences of human behavior

Joint event with OHST.
This talk examines the evidential and argumentative structures of a subset of current sciences of human behavior. The focus will be on approaches in behavior genetics, neurophysiology and anatomy, developmental biology and psychology, and approaches that combine one or more of these in interactive models. I will argue that these approaches, some of which are frequently represented as in empirical conflict one with another, are not, properly understood, in a conflict that can be empirically settled, nor are they reducible to one fundamental approach. Some of the consequences of taking this pluralist stance will be explored.