University of Calgary

# All LogBlog Posts

## Carnap Action in Paris

Submitted by Richard Zach on Sat, 05/16/2009 - 6:34am

In between thinking and lecturing about the epsilon-calculus, I'm in Paris for a few days: it's where all the Carnap action is right now. Heard wonderful talks by the likes of Steve Awodey, Dan Isaacson, Alan Richardson, Erich Reck, Delphine Chapuis-Schmitz, and Tom Uebel, unfortunately missed those by Michael Beaney, Juliet Floyd, and Rick Creath, and looking forward to some by André Carus, Gottfried Gabriel, Peter Hylton, Thomas Morman, and Pierre Wagner today. Thanks to Pierre for putting on this exciting conference!

## Robert K. Meyer, 1932-2009

Submitted by Richard Zach on Sat, 05/09/2009 - 12:47pm

Bob Meyer, emeritus professor of logic and philosophy at ANU, died last Thursday at the age of 77. He worked mainly on relevant logics and entailment, and is remembered not just for his work in logic, but also his wit and humor.

Dave Chalmers and Greg Restall remind us of the paper "God exists!", in which Bob proved that the existence of God is equivalent to the Axiom of Choice, and the Manifesto of the Logician's Liberation League.

UPDATE: Obit from the ASL Newsletter:

Robert Kenneth (Bob) Meyer, a major contributor in the field of non-classical logics, and a central figure on the Australasian logical scene, died in Canberra on May 6, 2009 at the age of 76, after a long struggle with cancer. Before his retirement as Professor in 1998, Meyer spent more than twenty years at the Australian National University, first in Philosophy at the Research School of Social Sciences, and subsequently in the Automated Reasoning Project, of which he was a founder. Meyer was born on May 27, 1932 in Philadelphia. He received a Bachelor of Divinity at Princeton Theological Seminary in 1956. After studying Japanese in Kyoto, he served as a missionary at the Christian Institute of Industrial Relations in Osaka from 1959 to 1962. Impelled by questions about the foundations of his religious beliefs, he enrolled as a graduate student in Philosophy at the University of Pittsburgh, receiving a Ph.D. in 1966 under the supervision of Nuel Belnap. From 1965 to 1974, he taught in Philosophy departments at West Virginia University, Rice University, Bryn Mawr College, Indiana University, and the Universities of Toronto and Pittsburgh. From 1974 until his retirement in 1998, he was at the Australian National University. Meyer served as the President of the Australasian Association for Logic in 1982 and was elected as a Fellow of the Australian Academy of the Humanities in the same year. Meyer was famous for his work in relevant logic and entailment. An early major contribution in the area was his proof (with J.M. Dunn) of the admissibility of the rule $\gamma$ in the logics $R$ and $E$. His best known work in the area is his series of papers with Richard Routley, expounding the relational semantics for relevant logics, and proving completeness theorems and many other results with its aid. Bob Meyer's brilliance as a logician and his infectious enthusiasm stimulated the growth of the Australian school of logic. In the 1980s, the research group surrounding him pioneered the use of computers in investigating logical problems. This group formed the nucleus of the Automated Reasoning Project, that later morphed into the Logic and Computation Group (both at ANU). Bob was noted not only for his enormous and unquenchable enthusiasm for logic, but also for his wit and humour. From 1969 onwards, he was the Maximum Leader of the Logicians Liberation League; for the manifesto of the LLL see http://users.rsise.anu.edu.au/~rkm/manifesto.html. Remarkable also is his contribution to rational theology, "God Exists!'' (published in Noûs 21: 345-61, 1987), in which he proves that God's existence (under a certain interpretation) is equivalent to the Axiom of Choice. Bob is remembered fondly by his family and his many friends and colleagues as a remarkable logician, and a wonderful human being.
Submitted by Richard Zach on Fri, 05/08/2009 - 6:55am

## Vienna Waits For Me

Submitted by Richard Zach on Tue, 05/05/2009 - 3:50am

At least I hope it does. I'll see in a couple of days, when I get there. Scheduled to give a talk on proof interpretations at the Institute Vienna Circle on Thursday (5 pm, Institut für Zeitgeschichte, Uni Wien Campus, Hof 1, 2. Stock, links). Friday, I start teaching a short course on the epsilon calculus at the TU Wien Logic Group. It'll be 10-2 in the seminar room of the department, 185/2, Favoritenstrasse 9, 3rd floor, yellow zone. Both of those will be in English, contrary to what you might think from the content of the linked pages.

## Women in Philosophy Employment Study Online

Submitted by Richard Zach on Wed, 04/29/2009 - 11:15pm

The May 2009 issue of the Proceedings and Addresses of the APA contain an interesting study conducted by the Committee on the Status of Women. It's online on the APA website:

CSW Jobs for Philosophers Employment Study

## 2009 Canadian Research Grants to Philosophers

Submitted by Richard Zach on Wed, 04/22/2009 - 6:42pm

SSHRC has posted the list of funded projects from the most recent Standard Research Grants competition. These grants are for three years. Last year's results are here. (Check the discussion in comments for info on what these grants are for, comparison with NEH grants, etc. UPDATE: Actually, the interesting discussion followed the 2006 list.)

This year's stats: 105 applications (2008: 92; 2007: 88; 2006: 85, 2005: 96, 2004: 92), 32 grants, for a success rate of 30% (2008: 30%; 2007: 29%; 2006: 37%, 2005: 38%, 2004: 48%). Full stats here.

Here's a list of the projects that jumped out at me as being philosophy projects or where I recognized the applicants as philosophers. So, the list is certainly incomplete! I haven't bothered sorting them alphabetically this time: they're sorted by province, east to west, then by university. The list doesn't give the department, nor does it give the grant selection committee, so some of these may have applied to a GSC other than philosophy--I don't think there's a way to tell. As always, please email with corrections and additions, or post in comments. Congratulations to all! And kudos to SSHRC for making the list of results available right away, and not with a delay of several months as in the past.

And a question: is it just my impression, or is Quebec overrepresented in philosophy SSHRC's? 42% of my list from Quebec, but only 27% of overall applications. It wasn't like this in the past few years. Maybe just coincidence? (After all, the prairies got nothing this year, it seems, but we had a pretty good showing last year.)

1. Renaud, François - Université de Moncton $25,787 Cicéron platonicien : la forme du dialogue et le débat entre scepticisme et dogmatisme 2. Charles, Syliane - Bishop's University$44,400
Entre physique et métaphysique, l'individu chez Spinoza
3. Danisch, Robert C. - Concordia University $59,000 Completing the linguistic turn: neopragmatism as rhetorical theory 4. Smith, Justin E.H. - Concordia University$76,874
Nature, human nature, and human difference: philosophical anthropology and the problem of diversity in the new science of nature, 1500-1800
5. Al-Saji, Alia - McGill University $39,957 Vision, race and ethics: a phenomenological investigation of racializing perception 6. Davies, David A. - McGill University$38,625
The ontology of multiple artworks: a performance-theoretic approach
7. Deslauriers, Marguerite L. - McGill University $80,237 Women, rationality and immortality: the reception of Plato and Aristotle in 16th and 17th C. feminist philosophy 8. McGilvray, James A. - McGill University$52,802
Philosophy and biolinguistics
9. Duchesneau, François - Université de Montréal $49,500 Monades et systèmes de la nature : Leibniz et sa postérité 10. Lepage, François - Université de Montréal$45,000
Les systèmes logiques de Lesniewski : une perspective contemporaine
11. Macdonald, Iain - Université de Montréal $35,724 Adorno and Heidegger: history and stakes of an unfinished debate 12. Lacroix, André - Université de Sherbrooke$71,660
Bégin, Luc - Université Laval
La formation chez les praticiens en éthique
13. Fisette, Denis - Université du Québec à Montréal $91,270 La philosophie de Franz Brentano via sa correspondance avec ses étudiants 14. Panaccio, Claude - Université du Québec à Montréal$71,540
Le nominalisme médiéval et l'externalisme : ontologie et théorie de l'esprit
15. Daigle, Christine - Brock University $42,873 Nietzsche as phenomenologist 16. Griffin, Nicholas J. - McMaster University$164,297
The collected letters of Bertrand Russell
17. Kumar, Rahul - Queen's University $51,300 Contractualism and the contours of morality 18. Russon, John E. - University of Guelph$27,445
Being through another: the idealist legacy in continental philosophy
19. Moggach, Douglas A. - University of Ottawa $53,832 Freedom and perfection: Kant's metaphysics of morals in context 20. Thompson, Evan T. - University of Toronto$41,640
The self and the brain: a neurophenomenological approach
21. Ripstein, Arthur S. - University of Toronto $71,050 Tort law as philosophy 22. Whiting, Jennifer E. - University of Toronto$58,000
Personal identity: practical yet metaphysical; or the ancient origins of Locke's account - and of any truly neo-Lockean account - of personal identity
23. Morrison, Margaret C. - University of Toronto $73,250 Computer simulation, modelling and experiment: knowledge at the boundaries 24. Mullin, Amy M. - University of Toronto$39,723
Children and parents: ethical relationships
25. Franks, Paul W. - University of Toronto $75,852 What is the human: Kantianism the development of the humanities and the threat of Nihilism 26. Nagel, Jennifer - University of Toronto$38,220
Metacognition and epistemic assessment
27. DeVidi, David M. - University of Waterloo $73,350 Pluralisms, mathematical and logical 28. Boran, Idil - York University$36,155
The idea of a market for carbon and its implications for philosophy and public policy
29. Shapiro, Lisa C. - Simon Fraser University $45,900 Emotions and sense perception in 17th and 18th century philosophy 30. Margolis, Eric - The University of British Columbia$64,250
The origins of human concepts
31. Aydede, Murat - The University of British Columbia $45,750 Pain and the nature of phenomenal consciousness 32. Woodcock, Scott - University of Victoria$46,108
Practical wisdom and naturalistic moral psychology

## Report on OpenProof Day 2009

Submitted by Richard Zach on Mon, 04/20/2009 - 5:50pm

[On March 27, 2009, Stanford/CSLI hosted a workshop on OpenProof (aka, the software behind Barwise and Etchemendy's Language, Proof, and Logic textbook). Alexei Angelides was there and provided the following report for LogBlog.]

On March 27th, CSLI and the OpenProof Project hosted a full day of presentation and discussion commemorating the, so to speak, tenth anniversary of the publication of Language, Proof, and Logic (LPL). I say "so to speak" because although the publication date was 1999, the date that appears on the first edition is 2000, a little tidbit of information that Etchemendy revealed was intentional, as both he and Barwise wanted its publication to symbolically coincide with the new millennium. The presentations were divided into six sections. Etchemendy began the day with a description of the history of the project; David Barker-Plummer followed with a description of the LPL package, including some of the new features that are going to be added to the next edition; this was followed by a roundtable discussion with three professors currently using the LPL courseware packages; then Richard Cox, one of the principal OpenProof researchers, presented some findings from data-mining the Grade Grinder corpus; Eric Pacuit, a modal logician currently at Stanford, presented on Kripke's World, a program intended to supplement work in modal logic; and, finally, Barker-Plummer ended the day with a description of OpenProof's main current research program, namely, HyperProof and OpenBox. I'll discuss a bit of the history, and some of the new features being added to LPL in the near future, and then describe just two of the presentations a bit. More info can be found here, including slides from each talk.

In the late '80s, Jon Barwise and John Etchemendy undertook work that attempted to blend different types of reasoning, primarily diagrammatic and sentential. Their work had two main aims, one theoretical, and the other pedagogical. On the theoretical side, Etch and Barwise were interested in challenging the "hegemony" of first-order predicate logic by arguing that reasoning with diagrams could be as rigorous as reasoning with a standard formal language. To this end, they developed so-called "heterogeneous" systems, formal systems that capture the structure of sentential or predicate reasoning (as in, e.g., sentential logic), and the structure of diagrammatic and visual reasoning (as in, e.g., reasoning with maps or Venn diagrams). On the pedagogical side, they were interested in using heterogeneous systems to enhance logic education, primarily at the college level, and so began to develop software packages that acted as supplements to the textbooks. By the mid-1990's, their work led to Hyperproof (1994) , a textbook and package of programs that implemented sentential reasoning alongside diagrammatic reasoning, making it possible to reason, say, with maps (or visual information more generally), and first-order sentences in the same contexts. Along with Tarski's World's first incarnation (1987), Turing's World (1986), and their The Language of First-Order Logic (1991), Hyperproof led to the first incarnation of LPL, a book that is nominally a course in first-order logic, but for which one of the programs allows students to evaluate the truth-values of sentences and the consequence relations between them, in a fully interpreted language called the "Blocks Language," by using the spatial and visual relationships between tetrahedra, cubes, and dodecahedra in the Tarski's World program.

Tarski's World is one of three programs designed to supplement a student's learning. The other two are Boole, a program designed to allow students to construct truth tables and test for truth-functionality and first-order consequence, and Fitch, a formal system for constructing proofs that includes the ability for teachers to allow and disallow certain rules to be used, and which includes a proof checker for students to verify their constructions. Of course, the software package also includes the Grade Grinder, which is like a very programmatic, 24-hour, mini-TA for students and instructors alike, giving some feedback to students who submit incorrect answers to it, and allowing teachers to relegate the more menial, possibly non-conceptual problems to the machine. (It includes, for students, the option of submitting solely to themselves in order to check if their answers are correct before submitting to the instructor.) Now, anyone who has used LPL knows how enormously helpful these programs are, both in terms of saving time for the professor using it, and pedagogically for the student, especially Tarski's World. Understanding how to abstract away from the meanings of the terms, and regard them as entirely uninterpreted has been, in my experience, the first road block for students. Tarski's World, though, acts as a kind of happy middle between the uninterpreted languages of first-order logic, and the interpreted kind we all grow up speaking.

However, anyone who has used LPL for anything more than an intro course also knows that software support drops off at chapter fifteen, the chapter in which we are introduced to first-order set theory, and after that, mathematical induction, and some of FOL's metatheory. In his presentation, Barker-Plummer noted that new editions of LPL rectify this. So, new editions enhance Fitch by adding the possibility of constructing inductive and set-theoretic proofs, the ability to "flag" lemmas, so that students do not have to reprove instances of, say, excluded middle, improved Henkin-Hintikka game play in Tarski's World, and a feature they're calling "goggles," in which the distinctions between tautological consequence, first-order consequence, and logical consequence are given a "visual" component. Thus, for example, if you're using your TautCon Goggles, only the sentential connectives are visible, and each instance of the same sentential letter gets assigned the same color, allowing the student to visualize the underlying logical structure of the argument. (Footnote: You might worry, as one audience member did, about how this might work for the (partially) colorblind or blind. An effective way to deal with this might be to have "goggled" areas shaded with variations in grey. For the blind, the problem is more general, obviously. For some recent work dealing with it see Jesse Alama, Patrick Girard, and Elizabeth Phillips's project on "brailling logic" here.) Finally, new editions of LPL will also include an ability for instructors to input their own exercises that are then gradable via the Grade Grinder, an addition, I think, that enhances the interaction between instructor and LPL, allowing instructors a bit more freedom in what they stress in their courses.

One of the most interesting presentations of the day was Cox's. Along with a few others (including Barker-Plummer), Cox has been data mining the results of the Grade Grinder in order to find the most common mistakes, and then attempting to give some explanation to those mistakes. Not only does this have interest in itself, since it's possible that such research leads to a better understanding of some of the cognitive processes underlying logical and, in at least one case as I'll explain in a second, visual reasoning. It also assists with updates to the LPL software, since by isolating the source of common errors in problem-solving, better feedback can be automatically generated by the Grade Grinder. They looked at two different exercises, one dealing with translations from English to FOL, and one dealing with the graphical interface between Tarski's World and the Blocks Language. For the first, the team selected an exercise of mid-range difficulty by looking at the number of submissions from beginning of data from the Grade Grinder (1999), rank ordering those submissions, and then choosing one with a high error rate, which turned out to be exercise 7.12 from chapter 7. (Footnote: Specifically, of 46,200 submissions, 27,473 were incorrect (59%), taken from a sample size of 4912 students, representing 5.6 incorrect sentences (out of 20).) Consider the following sentence:

• if a is a tetrahedron, then it is in front of d.

On this problem (7.12.1), students were in error 43%. But now consider:

• c is to the right of a, provided it (i.e., c) is small.

On this problem (7.12.4), students were in error 66%, reflecting the fact that when word order between natural language and first-order languages is not preserved in translation, the error rate rises. One frequent example that logic instructors everywhere will recognize immediately is the "only if" construction in English. As LPL points out, "only if" introduces a necessary condition. Even after much instruction, however, students are apt to translate "S only if P" as:

• P ? S.

Cox and his team found that, across all twenty sentences in problem 7.12, the frequency of error in translating from "only if" to FOL was 75.43%, a far higher error rate than any other conditional translation error. While many of their results dealing with translations from natural language into FOL are unsurprising, it is nice to see some statistics backing up anecdotal experience.

On the other hand, the third error the data miners canvassed was one dealing with the interface between Tarski's World and translations from natural language to FOL, this time with an unexpected result. Again choosing a problem of medium difficulty, 7.15, they found that one subproblem in particular, 7.15.7, suggested that students have a harder time with processing visual (sizes, etc.), as opposed to spatial (shapes, etc.) information. In the problem you are asked to start a sentence file in Tarski's World, and translate:

• d is a small dodecahedron unless a is small.

Note again the intuitively problematic conditional. Once the student has translated the sentence into FOL, she is asked to figure out the sizes and shapes of the objects named in all 12 subproblems. Then, the student is asked to build a world in Tarski's World where all of the sentences are jointly true. The point is that the student is asked to translate from English to FOL, then to determine, based on her translations, the relevant visual and spatial information, and then, based on her classification of that information, actually produce the required visual and spatial arrangement. In other words, the exercise takes the student from linguistic processing to visual and spatial processing. Cox and company found that for the above sentence, 92% of errors involved the size of d. But only 24% of errors involved its shape. (16% involved both.) So, given that such a high error rate was not found in cases involving translations between English and FOL that did not also involve the graphical interface, Cox suggested, based on research by Knauff (2001), that the information about an object's size may have negative effects on reasoning when it's not relevant to the problem. (Footnote: Of course, there are other interpretations of the data here, and Cox was careful to go through a few. I found this the most interesting for the purposes of making a distinction between linguistic, visual, and spatial types of reasoning. But see his slides (on the website) for more.)

Pacuit's presentation was on another new, but currently in progress, feature of the OpenProof project. Kripke's World, which the developers hope to have ready to accompany an as of yet unwritten text, is a means of evaluating modal formulae that is, in most respects, just like Tarski's World. Salient differences are that rather than using a propositional modal language, the developers have chosen a first-order modal language over the Blocks Language. Hence, upon opening Kripke's World, one is able to form sentences such as:

• ?? x Tet(x).

The states at which modal formulae are evaluated are Blocks Worlds. The interface is essentially the same as the Tarski's World interface, the difference being that multiple Blocks Worlds are constructible where there is an accessibility relation (reflexive, symmetric, Euclidean, and so on, selected from a useful drop down scroll list) between the various Kripke's Worlds that one constructs. So, for example, if one starts in a world where an object a is a cube, then in order for:

• ?Cube(a)

to be true, the object named by a must be a cube in all Kripke Worlds accessible from the initial world, reflecting the fact that names are rigid designators. Moreover, because the developers use a first-order modal logic, in Kripke's World objects have haecceity, a fact which is reflected in the software as well, as the "thisness" (represented in Kripke's World by Greek lettering) for an object in the initial world carries over to all subsequent worlds in which the formula containing it is evaluated. One feature, or problem--depending on who's looking--of their approach is that Kripke's World seems to be a nice approach for philosophers who are trying to emphasize the philosophical aspects of modal logic. But for logicians, who commonly emphasize the metatheoretic properties of modal logics, and its relation to (fragments of) first-order logic, it might not be as useful. For example, it doesn't touch on the myriad applications of modal logic, such as epistemic or deontic logic. Moreover, in my opinion another drawback of Kripke's World is that it uses the same graphical interface as Tarski's World. The salient difference is that more than one Tarski World is constructible, given an accessibility relation, but that only seems to visually complicate matters, whereas one of the nice things about Tarski's World is that, visually, it's so easy to use. Surely there's some happy middle, here. In any event, Pacuit brought up some very nice questions about Kripke's World, including one that has received much airtime at Stanford lately, namely, how best to integrate an introduction to modal logic within a standard course on first-order logic. Suffice it to say that this discussion is ongoing.

One final note on Barker-Plummer's final presentation, on OpenProof's OpenBox project. The OpenBox, a direct descendent of Barwise and Etchemendy's theoretical work that led to Hyperproof, is due to appear soon, and, as emerged from the discussion, is the most extant and up-to-date version of the original Hyperproof platform. As such, the intention is to integrate diagrammatic and sentential reasoning into a single software package. Now, however, the architecture of the program allows users to modify programs by plugging in "components," new interfaces that are uploaded by the users themselves, making the project entirely interactive. Hence, for example, an architect who wants to plan his next project might upload his design specifications, and then use the reasoning environment given by OpenBox to find his available possibilities, given his specifications. Or, as Etchemendy pointed out, one might use it to modify a picture, for example, in Adobe Photoshop, but use Openbox to save the history of all possibilities that had been available before a given modification to the picture. Of course, more theoretical uses are available, but the point of the components is to allow users to build their own reasoning specifications into different contexts, visual, spatial, sentential, and various combinations of the three. Barker-Plummer intends this to be a generalization of the notion of justification, and to the extent that it captures the reason for which an inference is made, whether in logical, architectural, or other contexts, this is correct. Indeed, it must be emphasized that maximal interaction between interface and user, and the systematic investigation of different types of reasoning, have been theoretical goals of the OpenProof Project since its inception, for it's led to a book, that led to a software and textbook package, that led to today's LPL, that led to OpenProof. So I hope, given their stress on interaction and the commemoration's fruitfulness, that more meetings like this take place.

## Choice & Inference: New Group Blog

Submitted by Richard Zach on Thu, 04/16/2009 - 2:58pm

Jake Chandler at Leuven's Centre for Logic and Analytic Philosophy, and Jonah Schupbach, currently at Tilburg's Center for Logic and Philosophy of Science, have started a new group blog, Choice & Inference:

Welcome to the new group blog, Choice & Inference! This blog provides a platform for dialogue and news within the fields of formal epistemology and decision theory, broadly construed. Topics include (but are not limited to) uncertain and ampliative inference, coherence, paradoxes of belief and / or action, belief revision, disagreement and consensus, causal discovery, epistemology of religion, etc. And the formal tools used to pursue questions within these topics include (but are not limited to) game theory and decision theory, formal learning theory, probability theory and statistics, networks and graphs, and formal logic.

## Awodey on Sets, Types, Categories and the Foundations of Mathematics

Submitted by Richard Zach on Thu, 04/16/2009 - 5:59am

There are a number of foundational schemes out there. ZFC set theory is perhaps the most widely known, but of course you can also develop math in type theory. And you can also do it in category theory. So what's the difference? Steve Awodey has an answer in a preprint of a paper, now posted on his web site: "From Sets to Types to Categories to Sets". Here's the introductory paragraphs:

Three different styles of foundations of mathematics are now commonplace: set theory, type theory, and category theory. How do they relate, and how do they differ? What advantages and disadvantages does each one have over the others? We pursue these questions by considering interpretations of each system into the others and examining the preservation and loss of mathematical content thereby.

In order to stay focused on the “big picture”, we merely sketch the overall form of each construction, referring to the literature for details. Each of the three steps considered below is based on more recent logical research than the preceding one. The first step from sets to types is essentially the familiar idea of set theoretic semantics for a syntactic system, i.e. giving a model; we take a brief glance at this step from the current point of view, mainly just to fix ideas and notation. The second step from types to categories is known to categorical logicians as the construction of a “syntactic category”; we give some specifics for the benefit of the reader who is not familiar with it. The third step from categories to sets is based on quite recent work, but captures in a precise way an intuition from the early days of foundational studies.

With these pieces in place, we can then draw some conclusions regarding the differences between the three schemes, and their relative merits. In particular, it is possible to state more precisely why the methods of category theory are more appropriate to philosophical structuralism.

UPDATE: Peter Smith had the good judgment of also quoting from the conclusion, where Steve makes the point that the advantage of the category-theoretic approach is that, of the three approaches, category theory is the system that allows formalization of only the structurally invariant mathematical facts, those that don't depend on specific features of the foundational scheme (say, where in the cumulative hierarchy something lives)--although you can have all that extra structure in the category-theoretic setting, if you want or need it.

## Travel grants for Women in Computability at CiE 2009

Submitted by Richard Zach on Thu, 04/16/2009 - 4:12am

This call for applications for Elsevier Foundation Travel Grants for junior female researchers for the CiE 2009 conference just came over the wire:

We are offering up to five travel grants for junior female researchers to come to CiE 2009. These grants cover the registration fee (at the early rate) plus a travel reimbursement of up to 300 EUR (after you submit original receipts).

In order to be considered for this grant, please send an e-mail to Elvira Mayordomo at: elvira@unizar.es

with the following information: a brief motivation, a short CV (at most two pages), and contact information for an academic reference. Preference will be given to applicants who present a paper (including informal presentations) - for instructions on how to submit an informal presentation, see:

http://www.math.uni-heidelberg.de/logic/cie2009/pb_informalpres.php

Please submit your Travel Grant application before 1 May 2009. Decisions will be communicated in mid May.

## Logical Positiv-its

Submitted by Richard Zach on Wed, 04/01/2009 - 5:39am

My colleague Marc Ereshefsky brought me back a book of sticky notes from LA: Logical Positivi-its. There are three: a defintional double arrow, one with a picture of Otto Neurath, and one with a picture of Wittgenstein with three check boxes: tautology, meaningless, or Schweigen (be silent).

## ESSLLI 2009 in Bordeaux

Submitted by Richard Zach on Wed, 04/01/2009 - 5:21am

If you'd rather go to France than Pittsburgh or LA, or you're not an undergrad student:

21st EUROPEAN SUMMER SCHOOL IN LOGIC, LANGUAGE AND INFORMATION

Bordeaux, July 20-31 2009

The European Summer School in Logic, Language and Information (ESSLLI) is organized every year by the Association for Logic, Language and Information (FoLLI) in different sites around Europe. The main focus of ESSLLI is on the interface between linguistics, logic and computation.

The 21st edition of ESSLLI will be held in Bordeaux, recently selected as a Unesco World Heritage site.

ESSLLI gathers about 500 people and offers a total of 48 courses and workshops, divided among foundational, introductory and advanced courses, and including a total of 6 workshops. The courses and workshops cover a wide variety of topics within the three areas of interest: Language and
Computation, Language and Logic, and Logic and Computation.

Registration for ESSLLI is open. Early registration rates are 225 euros for students and 350 euros for others.

Early registration deadline: 1st of May 2009.

There is a limited number of fee waivers available for students who want
to spend some time assisting the organizing committee during ESSLLI.

## Antonelli, Belnap, Segerberg in Calgary this Weekend

Submitted by Richard Zach on Tue, 03/24/2009 - 11:13pm

We're having a little logic conference this weekend in Calgary. If you're in the area, please come! All talks in 1253 Social Sciences, University of Calgary. Relevant papers may be found by following the links below

## Nuel Belnap (Pittsburgh)

Friday, March 27, 4 pm

### Truth Values, Neither-True-Nor-False, and Supervaluations

My oral remarks are based on an essay to appear in Studia Logica. (The essay evidently has more sections that I can adequately treat in the time allotted.) The first section defends reliance on truth values against those who, on nominalistic grounds, would uniformly substitute a truth predicate. I rehearse with great brevity some practical, Carnapian advantages of working with truth values in logic. In the second section, after introducing the key idea of "auxiliary parameters," I look at several cases in which logics involve, as part of their semantics, an extra auxiliary parameter to which truth is relativized, a parameter that caters to special kinds of sentences. In many cases, this facility is said to produce truth values for sentences that on the face of it seem neither true nor false. Often enough, in this situation appeal is made to the method of supervaluations, which operate by "quantifying out" auxiliary parameters, and thereby produce something like a truth value. Logics of this kind exhibit striking differences. I first consider the role that Tarski gives to supervaluation in first order logic, and then, after an interlude that asks whether neither-true-nor-false is itself a truth value. I consider sentences with non-denoting terms, vague sentences, ambiguous sentences, paradoxical sentences, and future-tensed sentences in indeterministic tense logic, I conclude my survey with a look at alethic modal logic considered as a cousin, and finish with a little "advice to supervaluationists," advice that is largely negative. The case for supervaluations as a road to truth is strong only when the auxiliary parameter that is "quantified out" is in fact irrelevant to the sentences of interest--as in Tarski's definition of 'truth' for classical logic. In all other cases, the best policy when reporting the results of supervaluation is to use only explicit phrases such as "settled true" or "determinately true," never dropping the qualification.

http://www.phil.ucalgary.ca/philosophy/node/410

## Krister Segerberg (Uppsala/Calgary)

Saturday, March 28, 10 am

I am trying to develop a dynamic deontic logic, the outlines of which I will sketch. To motivate this attempt, and also to assess its merits, I will consider three classic paradoxes: those due to Chisholm, Ross, and Forrester.

## Aldo Antonelli (Davis)

Saturday, March 28, 2 pm

### Free Quantification and Logical Invariance

In order to present the problem of providing a natural and well-behaved semantics for (positive) free logic, a number of approaches are considered, some old, some new -- all of which are found wanting in some respect or other. We then shift our perspective in order to tackle the problem from the standpoint of the theory of generalized quantifiers, with accompanying emphasis on permutation invariance as a characteristic feature of logical notions. This will finally result in a natural and well-motivated semantic theory for positive free logic -- which, however, also leads to questioning the logical nature of free quantification.

http://www.phil.ucalgary.ca/philosophy/node/493

## Who's The Most Famous Philosopher of the 20th Century?

Submitted by Richard Zach on Tue, 03/03/2009 - 1:56am

On Leiter's blog there was a poll on the question "who's the most important philosopher of the 20th century", prompted by the unqualified assertion by Jim Holt in a NYT book review that that would be Wittgenstein. The results were widely debated, e.g., on Crooked Timber. The reason the results were contentious, I think, is because the methodology was severely flawed and consequently the results were widely off. Of course the proper methodology would be to find a property that correlates with the property you're interested in, but that is objectively measurable. Obviously, the property you should be interested in here is fame. Below a ranking of the philosophers included in Leiter's list, sorted by fame (measured in dBHa, the international logarithmic unit of fame, see Schulman 2009).

 Rank Name Rank Leiter Rank dBHa 1 Bertrand Russell 1 2 -1.9 2 Jean-Paul Sartre 2 10 -2.25 3 Michel Foucault 3 7 -2.75 4 Jürgen Habermas 4 20 -2.89 5 John Dewey 5 11 -3.83 6 Simone de Beauvoir -3.98 7 Martin Heidegger 6 4 -4.01 8 Hannah Arendt -4.26 9 Ludwig Wittgenstein 7 1 -6.29 10 Iris Murdoch -6.9 11 Richard Rorty 8 22 -6.96 12 Gilles Deleuze 9 21 -7.28 13 Karl Popper 10 8 -7.44 14 Theodor Adorno 11 16 -7.91 15 Hans-Georg Gadamer 12 27 -8.03 16 Henri Bergson 13 24 -8.28 17 John Rawls 14 5 -8.75 18 Judith Butler -9.43 19 Maurice Merleau-Ponty 15 23 -9.48 20 Alfred North Whitehead 16 26 -9.84 21 Julia Kristeva -10.37 22 Bernard Williams 17 12 -10.38 23 Donald Davidson 18 17 -10.62 24 Ernst Cassirer 19 27 -10.69 25 Hilary Putnam 20 18 -10.78 26 Luce Irigaray -11.21 27 G. E. Moore 21 15 -12.02 28 W. V. O. Quine 22 6 -12.83 29 Martha Nussbaum -14.29 30 Rudolf Carnap 23 13 -14.65 31 Donna Haraway -14.95 32 Elizabeth Anscombe -15.3 33 P. F. Strawson 24 24 -17.08 34 Alfred Tarski 25 18 -17.14 35 C.I. Lewis 26 29 -17.88 36 Saul Kripke 27 9 -18.46 37 Michael Dummett 28 30 -18.52 38 Wilfrid Sellars 29 14 -18.79 39 Susan Haack -21.89 40 Philippa Foot -22.04 41 David K. Lewis 30 3 -23.06

The top 8 are B-list celebrities, 9-31 are C-list, by Schulman's standard.

UPDATE: Prompted by Rob Wilson's comment, I added a number of women philosophers to Leiter's original list.

References

Schulman, E. 2009, "Measuring Fame Quantitatively. IV. Who's the Most Famous of Them All?" Annals of Improbable Research Online, February 28. (see also AIR February 28)

## Beth Dissertation Prize Call for Nominations

Submitted by Richard Zach on Sat, 02/28/2009 - 7:19pm

FOLLI is soliciting nominations for the 2009 Beth Dissertation Prize in Logic, Language, and Information.

Since 2002, FoLLI (the European Association for Logic, Language, and Information, www.folli.org) awards the E. W. Beth Dissertation Prize to outstanding dissertations in the fields of Logic, Language, and Information. We invite submissions for the best dissertation which resulted in a Ph.D. degree in the year 2008. The dissertations will be judged on technical depth and strength, originality, and impact made in at least two of the three fields of Logic, Language, and Computation. Inter-disciplinarity is an important feature of the theses competing for the E. W. Beth Dissertation Prize.

## Openproof Day 2009

Submitted by Richard Zach on Sat, 02/28/2009 - 6:26pm

On March 27, 2009, the people behind Language Proof and Logic will have a little meeting on the various courseware packages they have now and are currently developing:

Openproof day will be a day of events discussing a variety of topics related to the work of the project, including:

* Presentation of existing courseware packages including plans for future improvements,
* Discussion with instructors on the use of existing courseware packages,
* Presentation of courseware packages for future release,
* Presentation of recent research in data mining student work in logic.

Wish I could go, but we'll have a logic event at Calgary with Aldo Antonelli, Nuel Belnap, and Krister Segerberg that weekend. If anyone wants to report on Openproof Day here, you're welcome to guest-blog.

Submitted by Richard Zach on Tue, 02/24/2009 - 6:01am

Not one but two logic summer schools for undergrads this year:

Carnegie Mellon Summer School in Logic and Formal Epistemology
June 8 to 26, with courses by Steve Awodey (Categories and Structures), Teddy Seidenfeld (Decisions and Games), and Jeremy Avigad (Logic and Formal Verification)
Apply by March 15

UCLA Logic Center 2009 Summer School for Undergraduates
July 13 to 31, with courses by Henry Towsner (First-order logic and Gödel's incompleteness theorem), Justin Palumbo (Forcing and independence in set theory), and Isaac Goldbring (Non-standard analysis)
Apply by March 30

Both of these are free, and UCLA promises to even pay a stipend!

## Canadian PhD Programs in the 2009 Philosophical Gourmet Report

Submitted by Richard Zach on Tue, 02/24/2009 - 1:32am

With the kind permission of Brian Leiter, here's a breakout of the Canadian philosophy departments by specialty according to the 2009 Philosophical Gourmet Report. Major changes over the last (2008-10) edition: The Guelph-Laurier-McMaster program is no longer ranked, and neither is Waterloo. The "local means", i.e., mean scores from Canadian evaluators, are no longer reported. That's a bit unfortunate, but it probably makes no difference as far as the rank-ordering goes. The numbers following the specialties are: the peer group the program falls in and the rounded mean score. See the overall rankings and the specialty rankings from the PGR for explanations. Compare specialty rankings for Canadian programs from the 2006-08 and from the 2004-06 report.

(Email or post comment if you find a mistake, please.)

 Program Ranked Specialties University of Toronto1 (3.6) Philosophy of Language 5 (21-36 / 3.0)Philosophy of Mind 3 (9-23 / 3.5)Metaphysics 5 (18-47 / 3.0)Philosophical Logic 5 (22-50 / 3.0)Ethics 3 (6-11 / 4.0)Metaethics 4 (16-35 / 3.0)Political Philosophy 3 (10-22/ 3.5)Philosophy of Law 3 (6-13 / 3.5)Applied Ethics 2 (3-7 / 4.0)General Philosophy of Science 3 (12-22 / 3.5)Philosophy of Biology 2 (3-8 / 4.0)Philosophy of Cognitive Science 4 (13-32 / 3.0)Decision, Rational Choice, and Game Theory 4 (10-27 / 3.0)Philosophy of Mathematics 5 (27-41 / 3.0)Mathematical Logic 4 (16-31 / 3.5)Ancient Philosophy 2 (2-4 / 4.5)Medieval Philosophy 1 (1-4 / 4.5)Early Modern: 17th Century 3 (10-21 / 3.5)Early Modern: 18th Century 3 (4-10 / 3.5)Kant 4 (18-33 / 3.0)19th Century Continental 3 (11-18 / 3.5)20th Century Continental 3 (11-31 / 3.0)American Pragmatism 2 (2-4 / 4.0)Feminist Philosophy 5 (21-38 / 3.0)Chinese Philosophy 4 (8-10 / 3.0) University of Western Ontario2 (2.7) Philosophical Logic 5 (22-50 / 3.0)General Philosophy of Science 2 (2-11 / 4.0)Philosophy of Physics 2 (2-5 / 4.5)Philosophy of Social Science 4 (14-32 / 3.0)Decision, Rational Choice, and Game Theory 4 (10-27 / 3.0)Philosophy of Mathematics 3 (3-15/ 4.0)Mathematical Logic 4 (16-31 / 3.5)Early Modern: 17th Century 3 (10-21 / 3.5)Early Modern: 18th Century 3 (4-10 / 3.5)Kant 4 (18-33 / 3.0)History of Analytic 3 (11-20 / 3.5)Feminist Philosophy 5 (21-38 / 3.0) McGill University3 (2.5) Ethics 5 (29-53/ 3.0)Philosophy of Art 4 (18-28 / 3.0)Philosophy of Mathematics 4 (16-26 / 3.5)Ancient Philosophy 5 (13-22 / 3.0)Medieval Philosophy 4 (10-19 / 3.0)Early Modern: 17th Century 4 (22-44 / 3.0)Kant 4 (18-33 / 3.0)History of Analytic 4 (21-34 / 3.0)Feminist Philosophy 5 (21-38 / 3.0) University of BritishColumbia4 (2.4) Philosophy of Mind 4 (24-51 / 3.0)Philosophy of Art 2 (4-16 / 4.0)General Philosophy of Science 4 (23-44 / 3.0)Philosophy of Biology 4 (17-27 / 3.0)Philosophy of Cognitive Science 4 (13-32 / 3.0)Philosophy of Mathematics 5 (27-41 / 3.0)Early Modern: 18th Century 4 (11-33 / 3.0)History of Analytic 4 (21-34 / 3.0) University of Alberta5 (2.1) Philosophy of Mind 4 (24-51 / 3.0)Philosophy of Biology 4 (17-27 / 3.0)Mathematical Logic 4 (16-31 / 3.5)History of Analytic 4 (21-34 / 3.0)American Pragmatism 4 (7-14 / 3.0)Feminist Philosophy 5 (21-38 / 3.0) Queen's University6 (2.0) Ethics 5 (29-53 / 3.0)Political Philosophy 3 (10-22/ 3.5)Applied Ethics 3 (8-23 / 3.5)Feminist Philosophy 5 (21-38 / 3.0) University of Calgary7 (1.9) Philosophical Logic 5 (22-50 / 3.0)Philosophy of Action (incl. Free Will) 3 (7-10 / 3.5)Philosophy of Biology 4 (17-27 / 3.0)Mathematical Logic 4 (16-31 / 3.5)American Pragmatism 4 (7-14 / 3.0) York University8 (1.8) American Pragmatism 4 (7-14 / 3.0) Simon Fraser University9 (1.7) Mathematical Logic 5 (32-40 / 3.0)Early Modern: 17th Century 4 (22-44 / 3.0) McMaster UniversityNot ranked Philosophy of Law 3 (6-13 / 3.5)History of Analytic 4 (21-34 / 3.0)

Submitted by Richard Zach on Tue, 02/24/2009 - 1:18am

The Conservative government's budget includes additional funding for Canada's granting councils to expand their graduate scholarship programs. The Social Sciences and Humanities Research Council of Canada stands to gain an additional \$17.5 million, or 500 additional PhD scholarships and 1,000 additional MA scholarships. The catch: SSHRC's money is earmarked for "business-related degrees".

If you're Canadian, please sign the petition against this circulated by Niki Ashton, MP.

There's also a Facebook group and a call for 2 weeks of action and an article in the Globe and Mail.

## Interpretations of Propositional Dynamic Logic

Submitted by Richard Zach on Mon, 02/09/2009 - 4:29am

In Krister Segerberg's modal logic seminar here in Calgary, we were talking about propositional dynamic logic last week. PDL was originally introduced (by Vaughn Pratt in the early 70's) to reason about programs. In the language, you have propositional variables but then also variables for (indeterministic) programs. Moreover, you have complex terms for programs, e.g., if ? and ? are programs then ? ? ? is "either do ? or do ?", ?;? is "first do ? then do ?", ?* is "do ? 0 or more times. If ? is a program term and ? is a formula, then [?]? means "after every execution of ?, ? is true".

The semantics for PDL is your regular Kripke semantics where W is a set of states, V maps propositional variables into ?(W), and R maps program variables into ?(W2). The idea is that V(?) is the set of states where ? holds, and v R(?) w if ? takes you from state w to state v (? may be nondeterministic, so it's a relation, not a function). The definition of ||- is as you'd expect, with w ||- [?]? if v ||- ? for all v so that w R(?) v. You can put in program constants, e.g., the program 0 that just freezes (R(0) = ?), the program 1 that does nothing and immediately halts (R(1) = ?W), and the completely indeterministic program that can take you to any state from any state (R(U) = W2).

Most of the people in the seminar are philosophers, not computer scientists, so we were talking a fair amount of time about how to interpret this semantics not in terms of programs. One way to think of the ?'s is as actions types: ? is an action type, [?]? means "? is true after every action of type ?", and w R(?) v if some action of type ? can take you from w to v. For instance, think of W as the set of chess configurations (together with whether it's black's or white's move). Then ? might be "move the king". But this is still pretty close to the programs-changing-state interpretation.

I was thinking of a completely different interpretation, and was wondering if anyone has thought about this interpretation and if it might have any use: In the "intended" interpretation, R(?) tells you which states you can get to from a given state by doing ?. But R(?) may be seen as an ordinary modal accessibility relation on W. On this interpretation, PDL turns into a parametrized multi-modal logic with operations on modalities: ? is an accessibility relation (e.g., U is the total relation--every world is accessible from every world), [?]? means "? is ?-necessary), and the operations on programs turn into operations on accessibility relations, e.g., 1 ? ? is the reflexive closure of ? and ?* is the transitive closure of ?. My hunch is that, maybe by adding some additional operations on the ?'s, this could make PDL into a logic of modalities in general.