“On modus ponens: a response to McGee and respondents” by Theresa Helke (31 Mar)

My presentation is on modus ponens, specifically Vann McGee’s counterexample to this rule of inference. I will ask ‘Does the general validity of modus ponens hold?’ and answer ‘Yes, huzzah!’ I will consider three responses to McGee (those of Walter Sinnott-Armstrong et al, E.J. Lowe and Joseph S. Fulda), demonstrate how each fail and present my own response. It saves the general validity of modus ponens by appealing to Dorothy Edgington’s suppositional view of indicative conditionals. Interestingly, in so doing, my response strengthens the case for this view.

Graduate Seminar Series.
Date: Tuesday, 31 Mar 2015
Time: 2 pm – 3 pm
Venue: Philosophy Resource Room (AS3 #05-23)
Speaker: Theresa Helke
Moderator: Tay Qing Lun

About the Speaker:

Department_Photo_Theresa_HelkeTheresa Helke joined the department in August 2014. She is the first Philosophy PhD candidate in the NUS/Yale-NUS joint supervision programme. Before, she majored in Logic and minored in Government at Smith College. Professors Jay Garfield and James Henle supervised her honours thesis (‘Brown v. Brown: The Limits of Logic in Law and Language’). Professor Chris Mortensen (University of Adelaide) and she co-authored an article which the British Journal of Aesthetics published in 2013 (‘How Many Impossible Images Did Escher Produce?’, (2013) 53 (4): 425-441). After working at the Royal Institute of International Affairs (Chatham House) in London and travelling to India, Thailand, Australia, New Zealand and Papua New Guinea, she read Law at the University of Cambridge. Now, she is interested in multiculturalism and, within it, feminism, migration, law and linguistics. Professor Jay Garfield, who currently teaches at both NUS and Yale-NUS, is supervising her dissertation. She is English but grew up in New York City, Geneva and Vienna. Having trained eight years as a circus artist, she enjoys riding her unicycle.

“Abstraction and Referential Indeterminacy” by Matthias Schirn (Nov 13)

In this talk, I shall critically discuss some issues related to Frege’s notion of logical object and his paradigms of second-order abstraction principles: Hume’s Principle and especially Axiom V. The focus is on the referential indeterminacy of value-range terms, Frege’s attempt to remove it as well as on his subsequent proof of referentiality for his formal language. Special attention will be paid to the assumptions that underly his overall strategy.

Philosophy Seminar Series
Date: Thursday, 13 Nov 2014
Time: 2pm – 4pm
Venue: AS3 #05-23
Speaker: Matthias Schirn, University of Munich
Moderator: Dr. Tang Weng Hong

About the Speaker:

SchirnCROPMatthias Schirn  is Professor of Philosophy at the University of Munich. His research interests are in the philosophy of logic and mathematics, proof theory, the philosophy of language, intensional semantics, epistemology and the philosophies of Kant, Frege, Hilbert, Russell and Wittgenstein. He also taught at the universities of Oxford (1976, 2014), Michigan State (1976-77), Cambridge (1977-78), Minnesota (1989), the State University of Campinas (1991), the National University of Buenos Aires (1992), the National Autonomous University of Mexico (1993, 1994, 1997), the Federal University of Ceará in Fortaleza (2003), the National University San Marcos in Lima (2009) and numerous other universities in Europe and Latin America. He gave invited talks at many of the most prestigious universities in Europe, the United States of America, Latin America, Asia and Australia. Since 2012 he is a member of the Munich Center for Mathematical Philosophy. He has published in Mind, Synthese, The British Journal for the Philosophy of Science, Erkenntnis, Dialectica, The Journal of Symbolic Logic, Reports on Mathematical Logic, History and Philosophy of Logic, Logique et Analyse, Axiomathes, Theoria, Kantstudien, and other international journals. He is currently preparing two books on Frege’s philosophy and his logic.

“Using Logic To Argue About Logic” by Ben Burgis (27 Mar)

In a famous letter to Graham Priest and JC Beall, David Lewis declined to be part of an anthology they were editing on the debate about the Law of Non-Contradiction. Twelve years before, Priest’s book ‘In Contradiction’ had put dialetheism—the position that some contradictions are actually true—on the map. By the time the anthology was being put together, a growing number of classical logicians saw Priest’s arguments as a challenge that had to be addressed. Lewis, however, was having none of it. “To conduct a debate, one needs common ground; principles in dispute cannot over course be used as common ground; and in this case, the principles not in dispute are so very much less certain than non-contradiction itself that it matters little whether or not a successful defense of non-contradiction could be based on them.”

If Lewis is right, then the debate about the LNC looks like an instance of epistemic peer disagreement—a disagreement that doesn’t trace back to any asymmetry in the disputants’ access to relevant evidence, or to any asymmetry in their ability to properly evaluate that evidence. Unfortunately, when we try to plug his position into any of the standard views about peer disagreement, the results are extremely counter-intuitive. Happily, I conclude that Lewis is wrong. Despite the apparent difficulties, it is entirely possible to provide rational arguments for basic logical principles.

Philosophy Seminar Series.
Date: Thursday, 27 Mar 2014
Time: 2 pm – 4 pm
Venue: Philosophy Resource Room (AS3 #05-23)
Speaker: Ben Burgis, Underwood International College
Moderator: Dr. Ben Blumson

About the Speaker:

croppedBen Burgis is a post-doc at Underwood International College in South Korea. His research interests involve philosophy of logic, philosophy of language, the Liar Paradox, and the question of why “nay” means “no” in English and “yes” in Korean

“The True and what might be the truth about ‘is true’: A critical examination of Frege’s views” by Matthias Schirn (24 Jan)

What Frege has bequeathed to us regarding the concept of truth is not a homogeneous, coherent and systematically worked out conception. It is rather an agglomeration of remarks, scattered throughout several of his writings, on the nature of judgement and assertion, the conception of the two truth-values the True and the False as the references of assertoric sentences (as objects), the relation of a (true) thought to the True, the role and the purportedly unique sense of the word “true” and its alleged redundancy on the level of both sense and assertion, the characterization of logic as the science of the most general laws of truth, the “truth-conditional“ approach concerning the semantics of his formal language — to mention some issues, but not all.

The core of my talk will be a critical examination of what Frege says in some key passages about truth, the True and “is true”. I shall only touch upon his treatment of the True in Grundgesetze since a proper analysis of it would require a separate talk. Where it seems useful and enlightening, aspects of the current discussion of the concept of truth (for example, the role of this concept in minimalism about truth) will be taken into account. I shall argue among other things (a) that Frege’s reflections on the relation of a (true) thought to the True are incoherent; (b) that he fails to offer a convincing argument for rejecting the view according to which a sentence of the form “The thought that p is true” expresses the subsumtion of a thought (qua object) under the concept is true; (c) that Frege seems to overlook the fact that in such a sentence, even if it is interpreted as expressing a subsumtion of this kind, we still have the relation of sense to reference, of a thought to a truth-value; (d) that he falls short of providing a cogent argument for the purported synonymy of “p” and “The thought that p is true” and thus for the alleged redundancy of “is true” on the semantic level; (e) that, contrary to what he says, he has to concede that the word “true” makes an essential contribution to the thought expressed by “The thought that p is true”; (f) that there are indispensable uses of the truth-predicate anyway, not only in sentences such as “Everything Peter says is true” but also, for example, in informal “metalogical” discourse (g) that, contrary to what Frege appears to claim, he is committed to acknowledging that true is a property (of true thoughts); (h) that it remains unclear what truth qua that which is acknowledged (not predicated) in a judgement is supposed to be if it is possibly neither the True nor the concept is true.

Philosophy Seminar Series.
Date: Thursday, 24 Jan 2013
Time: 2pm – 4pm
Venue: Philosophy Resource Room (AS3 #05-23)
Speaker: Matthias Schirn, Professor, Department of Philosophy, University of Munich
Moderator: Dr. Ben Blumson

About the Speaker: 

Mathias Schirn is a professor of analytical philosophy at the University of Munich. His research interests are in the philosophy of logic and mathematics, the philosophy of language, epistemology and the more recent history of philosophy and logic with particular emphasis on the work of Gottlob Frege.

He held visiting positions at the universities of Oxford, Cambridge, Harvard, Berkeley, Minnesota (Twin Cities), Mexico City (UNAM), Buenos Aires, São Paulo and several other universities in Europe, the United States and Latin America.

He published in The Journal of Symbolic Logic, Mind, The Philosophical Review, Synthese, Erkenntnis, History and Philosophy of Logic, Logique et Analyse, The Bristish Journal for the Philosophy of Science, Metascience, Dialectica, Axiomathes, Kantstudien, Theoria, Crítica, Manuscrito and other international journals.

He published two books on the philosophy of language (one in German and one in Portuguese with Guido Imaguire), edited several books including Frege, Importance and Legacy, de Gruyter, Berlin New York, and The Philosophy of Mathematics Today, Oxford University Press, Oxford and he is now preparing a book with the title Foundations of Logic and Mathematics. Essays on Frege and another with the title Zahl und Begriff, Untersuchungen zu Freges Philosophie der Mathematik.

Among his hobbies are chamber music (especially string quartets), jazz, Roman languages, visits to Latin America and sports (especially bike racing competitions).

“A Venn Diagrammatical Analysis of Set Membership and Identity” by Robert Boyles (22 Nov)

In elementary logic, Venn diagrams are used to represent categorical statements and analyze and evaluate categorical syllogisms. Thus, the four traditional categorical statements, viz., A, E, I, and O, have their respective Venn diagrams. Also, the validity of syllogisms is easily determined by using Venn diagrams. Though the Venn diagram is a powerful analytical tool, it still has limitations. For one, it fails to represent singular statements of the form, “a is F;” in another, it fails to represent identity statements of the form, “a is b.” Since this is so, it follows that it also fails to give an account of the validity of some obviously valid inferences that contains these types of statements as constituents (e.g., All men are mortal. Socrates is a man. So, Socrates is mortal). In this paper, we offer a way of supplementing the rules of the Venn diagram so that it could surpass these limitations. To go about this, we take the standard principles of Venn diagrams at face value. Next, we add some formation rules that would account for membership and identity. Note that these rules are consistent with the rules of first-order logic and set theory. Finally, we shall demonstrate how this reformulated Venn diagram technique is supposed to work.

Philosophy Seminar Series.
Date: Thursday, 22 Nov 2012
Time: 2pm – 4pm
Venue: Philosophy Resource Room (AS3 #05-23)
Speaker: Sidney Diamante, Lecturer in Philosophy, De La Salle University, Manila, Philippines
Moderator: Dr. Neil Sinhababu

About the Speaker: 

Robert James Boyles is a lecturer in philosophy at De La Salle University-Manila. He earned his Master in Philosophical Research from the same school.