CANCELLED
What Ramsey Got Right
Prof Huw Price (Cambridge University)
Columbia University Seminar on Logic, Probability, and Games
Abstract. In his late paper ‘General propositions and causality’ (1929) Ramsey articulates what seems to be a version of the principle that deliberation crowds out prediction (DCoP), saying that our present action is “an ultimate and the only ultimate contingency”. He links this to the direction of causation, and to the fact that we take the future to be open but the past fixed. I will discuss what I take to be right and important about Ramsey’s proposal, and link it to the puzzling stand-off between friends and enemies of DCoP.
We will be having dinner right after the meeting at the faculty house. Please let Robby (jrf2162@columbia.edu) know if you will be joining us so that I can make an appropriate reservation (please be advised that at this point the university only agrees to cover the expenses of the speaker and the rapporteur and that the cost for all others is $25, payable by cash or check).
SHIGENORI NAGATOMO (Temple University)
With responses from:
GRAHAM PRIEST (CUNY Graduate Center)
Please join us at Columbia University’s Religion Department on FRIDAY, APRIL 8th at 5:30PM for his lecture entitled:
“The Logic of Not: An Invitation to an Holistic Mode of Thinking”
This presentation extends an invitation to an holistic mode of understanding to those who are concerned with current global situations. It thematically deals with the logic that appears in the sutra called the Diamond Sutra which belongs to the prajñāpāaramitā literature of Mahayana Buddhism. This logic is called “logic of not” because a negation appears in the formulation of the idea of identity as is expressed in the following: “A is not A, therefore it is A.” This logic cuts against the grain of the assumptions which the mode of thinking predominant in the Western philosophical tradition accepts as its modus operandi, namely the conceptual paradigm of the “either-or ego-logical dualistic standpoint.” This presentation argues that this paradigm generates a problem of fragmentation, which we take to be the root of many of the problems we face today, by analyzing the phrases such as “either-or,” “dualistic” and “ego-logical.” It then turns to an analysis of “the logic of not” by showing how it differs from Aristotle’s logic, while providing the philosophical reasons why the Diamond Sutra formulates its understanding of reality in terms of “the logic of not.” With this clarification, the presentation discusses how a transparency of mind and the idea of interdependency are necessary for achieving an holistic perspective, i.e., to understand things holistically. This mode of thinking will be effective to correct the problem of fragmentation, for example, in dealing with such topics as I knowing myself, the I-thou relationship, and environmental concerns.
…
April 29: Sara McClintock (Emory University)
We will provide more information regarding the topic of each speaker’s
presentation as the semester progresses. We hope to see you all at what
promises to be a semester of discussion and engagement.
The 1st Latinx Philosophers Conference is an initiative of some Latin American PhD candidates in the Columbia Philosophy Department. We hope to initiate a tradition of annual conferences to serve the following ends. First, to foster the creation and development of a Latinx Philosophers Network in the United States. This network, in turn, will help us provide a space for camaraderie and collaborative work, as well as identify and pursue the common interests of Latinx Philosophers in the U.S. Second, to provide a space for discussing issues of particular relevance to Latinx from a philosophical perspective.
The conference will take place on April 29-30 and will be organized around two clusters of topics. The first day will be devoted to issues in Epistemology, Logic, Metaphysics and Philosophy of Science. The second day will focus on Ethics, Social and Political Philosophy, Feminist Philosophy, Philosophy of Race, and Latin American Philosophy. We are happy to announce that Otavio Bueno and Jorge Gracia will be our keynote speakers for each day, respectively.
We invite graduate students who identify as Latinx or who are interested in forming part of the Latino/a Philosophers Network to submit papers on any of the topics mentioned above. We encourage submissions by women. We also encourage submissions that discuss issues relevant to the Latinx experience.
Papers should not exceed 4000 words (or the equivalent of a 30-minute presentation). They should be prepared for blind review and sent as a PDF file to latinophilosophersnetwork@gmail.com. In a separate PDF attachment, please include your name, academic affiliation, email address, telephone number, paper title, and an abstract of no more than 250 words. Any questions can be directed to César Cabezas (cgc2125@columbia.edu), or Ignacio Ojea (ignacio.ojea@columbia.edu). Acceptances will be announced by March 15.
This event is supported by:
MAP (Minorities and Philosophy), and
The Center for Race, Philosophy and Social Justice at Columbia University
Heart of DARCness
Huw Price (University of Cambridge)
4:10 pm, Thursday, October 13th, 2016
Faculty House, Columbia University
Abstract. Alan Hajek has recently criticised the thesis that Deliberation Crowds Out Prediction (renaming it the DARC thesis, for ‘Deliberation Annihilates Reflective Credence’). Hajek’s paper has reinforced my sense that proponents and opponents of this thesis often talk past one other. To avoid confusions of this kind we need to dissect our way to the heart of DARCness, and to distinguish it from various claims for which it is liable to be mistaken. In this talk, based on joint work with Yang Liu, I do some of this anatomical work. Properly understood, I argue, the heart is in good shape, and untouched by Hajek’s jabs at surrounding tissue. Moreover, a feature that Hajek takes to be problem for the DARC thesis – that it commits us to widespread ‘credal gaps’ – turns out to be a common and benign feature of a broad class of cases, of which deliberation is easily seen to be one.
Rationalizability, originally proposed by Bernheim and Pearce, generalizes the notion of Nash equilibrium. Nash equilibrium requires common knowledge of strategies. Rationalizability only requires common knowledge of rationality. However, their original notion assumes that the payoffs are common knowledge. I.e. agents do know what world they are in, but may be ignorant of what other agents are playing.
We generalize the original notion of rationalizability to consider situations where agents do not know what world they are in, or where some know but others do not know. Agents who know something about the world can take advantage of their superior knowledge. It may also happen that both Ann and Bob know about the world but Ann does not know that Bob knows. How might they act?
We will show how a notion of rationalizability in the context of partial knowledge, represented by a Kripke structure, can be developed.
Gödel’s disjunction asserts that either “the mind cannot be mechanized” or “there are absolutely undecidable statements.” Arguments are examined for and against each disjunct in the context of precise frameworks governing the notions of absolute provability and truth. The focus is on Penrose’s new argument, which interestingly involves type-free truth. In order to reconstruct Penrose’s argument, a system, DKT, is devised for absolute provability and type-free truth. It turns out that in this setting there are actually two versions of the disjunction and its disjuncts. The first, fully general versions end up being (provably) indeterminate. The second, restricted versions end up being (provably) determinate, and so, in this case there is at least an initial prospect of success. However, in this case it will be seen that although the disjunction itself is provable, neither disjunct is provable nor refutable in the framework.
UNIVERSITY SEMINAR ON LOGIC, PROBABILITY, AND GAMES
Gödel’s Disjunction
Peter Koellner (Harvard University)
5:00 pm, Friday, April 7th, 2017
716 Philosophy Hall, Columbia University
The umwelt is a notion invented by the Baltic-German biologist Jakob von Uexküll. It represents how a creature, an animal, a child or even an adult “sees” the world and is a precursor to the Wumpus world in contemporary AI literature. A fly is caught in a spider’s web because its vision is too coarse to see the fine threads of the web. Thus though the web is part of the world, it is not a part of the fly’s umwelt. Similarly a tick will suck not only on blood but also on any warm liquid covered by a membrane. In the tick’s umwelt, the blood and the warm liquid are “the same”.
We represent an umwelt as a homomorphic image of the real world in which the creature, whatever it might be, has some perceptions, some powers, and some preferences (utilities for convenience). Thus we can calculate the average utility of an umwelt and also the utilities of two creatures combining their umwelts into a symbiosis.
A creature may also have a “theory” which is a map from sets of atomic sentences to sets of atomic sentences. Atomic sentences which are observed may allow the creature to infer other atomic sentences not observed. This weak but useful notion of theory bypasses some of Davidson’s objections to animals having beliefs.
Russell, Stuart J., and Peter Norvig. “Artificial intelligence: a modern approach (International Edition).” (2002).
Von Uexküll, J., von Uexküll, M., & O’Neil, J. D. (2010). A foray into the worlds of animals and humans: With a theory of meaning. U of Minnesota Press.
We examine general decision problems with loss functions that are bounded below. We allow the loss function to assume the value ∞. No other assumptions are made about the action space, the types of data available, the types of non-randomized decision rules allowed, or the parameter space. By allowing prior distributions and the randomizations in randomized rules to be finitely-additive, we find very general complete class and minimax theorems. Specifically, under the sole assumption that the loss function is bounded below, every decision problem has a minimal complete class and all admissible rules are Bayes rules. Also, every decision problem has a minimax rule and a least-favorable distribution and every minimax rule is Bayes with respect to the least-favorable distribution. Some special care is required to deal properly with infinite-valued risk functions and integrals taking infinite values. This talk will focus on some examples and the major differences between finitely-additive and countably-additive decision theory. This is joint work with Teddy Seidenfeld, Jay Kadane, and Rafael Stern.
UNIVERSITY SEMINAR ON LOGIC, PROBABILITY, AND GAMES
Finitely-Additive Decision Theory
Mark Schervish (Carnegie Mellon)
4:10 pm, Friday, February 16th, 2018
Faculty House, Columbia University
Elliot Paul, assistant professor of philosophy, and Joan Snitzer, cochair and director of visual arts in the Department of Art History, come together to discuss the relationship between creative expression and appreciation in this installment of From the Faculty Lounge. Paul and Snitzer will explore creativity’s role in our happiness and moral choices, and how an artist’s ownership of their creativity compares to an audience’s influence.
Moderated by Provost Linda Bell
Space is limited and available on a first-come, first-served basis. Please arrive early as this event will be filmed and doors will close promptly at 6:30 PM.
From the Faculty Lounge
What is Creativity?
Thursday, May 3, 2018
6:30 PM
Sulzberger Parlor, 3rd Floor Barnard Hall
For more information, visit barnard.edu/events. View previously recorded conversations here.
Two proof-systems P and P* are said to be complementary when one proves exactly the non-theorems of the other. Complementary systems come as a particular kind of refutation calculi whose patterns of inference always work by inferring unprovable conclusions form unprovable premises. In the first part of my talk, I will focus on LK*, the sequent system complementing Gentzen’s system LK for classical logic. I will show, then, how to enrich LK* with two admissible (unary) cut rules, which allow for a simple and efficient cut-elimination algorithm. In particular, two facts will be highlighted: 1) for any given provable sequent, complementary cut-elimination always returns one of its simplest proofs, and 2) provable LK* sequents turn out to be “deductively polarized” by the empty sequent. In the second part, I will observe how an alternative complementary sequent system can be obtained by slightly modifying the Gentzen-Schütte system G3. I will finally show how this move could pave the way for a novel approach to multi-valuedness and proof-theoretic semantics for classical logic.