Logic Matters

It seems only yesterday that the fourth edition came out: but — as I found in the CUP bookshop today — there’s now a fifth edition of Computability and Logic. The preface announces that the main revision in this addition is a “simplification of the treatment of the representability of recursive functions”. And the material on Robinson Arithmetic has been rewritten, and there’s a more explicit discussion of the two uses we can make of Church’s Thesis (essential and eliminable).

I confess to still perhaps preferring the more spartan elegance of the early editions. And I think that the book has always been, then and now, rather harder for students than the authors intended (which was one reason that I imagined that there was room for my Gödel book, even though it criss-crosses over quite a bit of the same territory). But credit where a great deal of credit is due: this is still a lovely book, full of good things and with some terrific explanations of tricky stuff. So hasten to your bookshop …

Heck, advancing years are a terrible thing. Apart from the obvious drawbacks — and let’s not go into those — you start forgetting stuff that once upon a time you kinda knew a bit about. Ok, the things that you’ve regularly lectured on/written about sort of stay in place, more or less. It’s the more peripheral stuff that you find has been dragged to trash by the passing of time. Humppphh. So there I was, sitting like an idiot in the math logic seminar, not having had time to do enough homework, and just not able to recover what I once knew(?) from Bell and Slomson’s Models and Ultraproducts. Duh. But then I suppose I can look on the bright side. There will be the fun of rediscovery rereading the book (which I recall as very good) before the math logic seminar gets a bit serious next term. Though I’m not sure that is much compensation.

Something very different I’m currently devouring for the first time as my late night reading — something I wanted to read when it came out, but I’ve only just got round to — is Orlando Figes’ Natasha’s Dance. I’m only about a quarter through but it is simply fantastic. He writes with a novelist’s flair, building up a multilayered picture that throws so much light on what is going on in Russian literature. It’s wonderfully readable. I’m bowled over in admiration. So back to it …

I’m back from Oxford where I was giving a talk at Dan Isaacson’s philosophy of maths seminar. I was a bit anxious about the occasion in advance as I knew that Michael Dummett still tends to go. In the event he did come, and nodded and smiled encouragingly from time to time, and said he enjoyed the talk as he left at the end of the discussion. Which has certainly made my week. The discussion was helpful (Dan was pressing me hard to be clearer), but the basic line of argument seemed to survive. Phew. So I’ll write up a version of this stuff over the next week and put it on my website. Watch for a link.

I’d not been to Oxford since The Daughter left about eight years ago: and I’m always struck anew how wonderful the place looks (even on a rainy late-autumn night). Cambridge really hasn’t anything to compare with Radcliffe Square, or indeed the streets around and about.

I spent more than I should have done in Blackwell’s. I’ve made a start since on James Ladyman and Don Ross’s Every Thing Must Go: Metaphysics Naturalized which I bought despite the outrageous price, gripped by reading the first twenty pages or so in the shop. Having now finished the first long chapter, I find myself in considerable agreement with their basic line. Indeed, I’d say they rather pull their punches in criticizing arm-chair metaphysics based — if based on science at all — on a grasp of science that stops round about A-level chemistry (as they rudely but fairly put it); and some of the discussion so far is a bit oracular. Still, there’s a lot of the book to come, so we’ll see how well they sharpen their points and hammer them home. So far, so rather good!