Mindblown: a blog about philosophy.

Sitting in a talk at CMU by Bill Tait on cut elimnation for predicative systems. His approach, in contrast to Rathjen and Takeuti, is to try to get the cut-elimination proof to be mostly (or even, only) about the proofs, and not about proofs and (mostly) ordinal notation systems. He’s using the original Tait calculus,…

David Chalmers and David Bourget are setting up a new online resource for papers in philosophy, for which they’re designing a taxonomy of philosophical topics to be used for classifying papers in the database. David asks For now, I’m calling for feedback from the philosophical community, either via e-mail or via comments on this blog.…

My former colleague Charlie Martin died last Thursday. He was a major figure in metaphysics, one of the first to talk about truthmakers. Obituaries here and here.

The venerable Swedish philosophy journal Theoria is published by Blackwell since this past March, and that means it is online, including the back issues. I’m not sure of the exact dates, but in the 70s, when Krister Segerberg was the editor-in-chief of that journal, Theoria was the place to publish modal logic and formal philosophy.…

One very common informal statement of Gödel’s theorem is that it shows that for any (sufficiently strong consistent blah blah) formal system, there are truths that it can’t prove. And if you don’t formulate Gödel’s incompleteness theorem that way, at least you state this as a corollary: Gödel’s theorem shows that truth and provability (in…

Today’s Dinosaur Comics was written by xkcd‘s Randall Munroe: Ryan North, the author of Dinosaur Comics, has used philosophical/logical themes in his comic as well, e.g., the Twin Earth comic, or the Post Hoc Ergo Propter Hoc comic, or the one on pragmatism. This one is pretty funny, too. Of course, you’ve all seen the…

Update on my old post on modal logic textbooks: Two new modal logic books I have recently come across: Nino B. Cocchiarella and Max A. Freund, Modal Logic: An Introduction to its Syntax and Semantics (Oxford, 2008) Walter Carnielli and Claudio Pizzi, Modalities and Multimodalities (Springer, 2008) Anyone already read these and have an opinion?…

If you’re going to be in Pittsburgh (at the PSA) in three weeks, please come to the Carnap Reception that Open Court is going to throw on Friday, Nov 7. I think it’ll be at 5:30. Vol. 1 of Carnap’s Collected Works will be presented. I expect there will be free drinks, too!

Theorem(e)‘s, that is, Henri Galinon‘s, page of links to free, online logic textbooks and survey texts has moved and is now updated.

Since I’m hanging out with a bunch of category theorists every Wednesday, web finds with “category theory” in them keep attracting my attention. A couple of weeks ago, I came across this book draft posted on arXiv: Atish Bagchi and Charles Wells, Graph-based Logic and Sketches At first I thought, cool!, a new book on…