Peter Smith's Blog, page 132
March 24, 2011
Belatedly lighting the candles
I've just noticed — looking through the archive of past posts to check that nothing has been badly messed about by the presentational update — that the first ever post here was on March 9th 2006. So I missed marking the blog's fifth birthday.
Belatedly noticing the occasion prompted to reading back through some of the archive. I'm a bit alarmed to find how much I've read and commented on that I seem to have clean forgotten about, and amused to see how much I've given away one way or another about my fads and prejudices. I'm rather relieved, though, to see that I've ranted a bit less than I thought I might have done (one restraining factor is that really letting rip about e.g. the AHRC or the upcoming REF exercise, not to mention the local theologians, wouldn't do me any harm but could cause various troubles for soon-to-be-ex-colleagues).
Anyway, that's 626 posts done and counting. What started as an experiment has become a very enjoyable if somewhat sporadic habit, and occasionally a good self-imposed discipline (to make inchoate thoughts fit for blogging). So, if the fates are kind, here's to another five years …
March 22, 2011
In praise of … Kristian Bezuidenhout
Who? Not a household name, to be sure. And a new name to me ten days ago. But we went to a concert in the startlingly starry Peterhouse Camerata Musica series to hear Viktoria Mullova playing three of the Beethoven sonatas. She was good (but not, to be picky, as magical as she can be). However, Kristian Bezuidenhout, her accompanist on a fortepiano, was the revelation of the evening. His instrument had a wonderful tone (the most attractive fortepiano I think I've heard) and his playing was spectacularly good, dazzling passage work when called for, but always very musical, and sensitively responsive to Mullova's playing. The combination of her playing on gut strings and his 1822 instrument worked perfectly. I can very warmly recommend their disk of the Kreutzer sonata and the earlier 3rd sonata (one of the other two pieces they played in Cambridge): I've now listened to it a few times with great enjoyment.
March 18, 2011
Under reconstruction
(Friday) I'm planning, over the next day or three, to experiment with updating Logic Matters with a classier new WordPress theme. I'm so far favouring the "Tarski" theme, not just because the name seems peculiarly appropriate for a logic blog, but because it is really clean and suitable for a text-heavy site.
(Saturday) For a while, I'm afraid some navigation may not be quite optimal. But you should now mostly be able again to find what you are looking for.
(Saturday later) Huh. Have for the moment gravitated back to the new WordPress default "Twenty Ten" theme …
(Saturday evening) Beginning to aesthetically tweak the Twenty Ten theme. Most navigation restored. Wot fun!
(After midnight) This style-tweaking malarky is mildly addictive and probably already past the point of worthwhile returns. To bed …
(Sunday morning) I've a stable "child" of the Twenty Ten theme working which I quite like. But I'm going to be experimenting with an alternative for an hour or so (Weaver, also based on Twenty Ten). Things could look horrible for a bit, since Weaver's defaults are crap. But it offers ease of customization without so much digging into css files. So here goes …
Huh. Why, Mr Weaver, write a front end for customizing all kinds of things — but not the most important? Text size, line spacing, and para spacing? Back to my hand-kludged "child" theme. Now I need to get a header sorted.
(Sunday evening) Well, I still need to design a header, but I think I've done enough intermittent tinkering for a while. Basically the layout is a just slightly tweaked version of the new default WordPress theme; it seems to work well enough in Safari and Firefox on Macs. So if it doesn't play nicely with your browser, then I guess you should blame WordPress or the browser.
(Monday) Well, maybe Bauhaus austerity, no fancy header graphic, is the way to go. Right: for the moment, redesign job largely done. And marking M. Phil. essays is over too. So it's back to thinking about ordinals … and also, at long last, back to reading Alan Weir's book. I'll be taking up blogging about that again next week. Watch this space!
Under reconstruction …
I'm planning, over the next day or three, to experiment with updating Logic Matters with a classier new theme. In the meantime, I'm afraid sidebar navigation is largely broken. Come back later if you currently can't find what you are looking for.
This exciting development is brought to you by constructive procrastination …
March 16, 2011
Tennenbaum without tears
Another week, another logic handout. This time on Tennenbaum's Theorem. Here's a reasonably stand-alone proof (based on one in Kaye's book) with some very quick concluding remarks on the question of the theorem's conceptual significance.
As always, comments are most welcome.
February 24, 2011
The MRDP theorem
I gave a rough-and-ready talk yesterday, introducing the MRDP theorem to some logic-minded philosophers (mostly postgrads). The aim was to explain what the theorem says and why it is interesting, rather than to talk about the proof in detail. Here's a slightly tidied version of my rough-and-ready handout.
I don't pretend to know a great deal about this stuff, so I'd like to hear about needed corrections: and suggestions for improvements and additions will be most welcome too.
February 20, 2011
Imogen Cooper plays Schubert … on YouTube
Thanks to Askonas Holt, her agents, three videos of Imogen Cooper playing at a concert in 2009 have just been posted on YouTube (the video isn't HD, but the sound is just fine). There is a nice performance of Schubert's Hungarian Melody D817, and a lovely short piece of Janacek, 'Good Night' from On an Overgrown Path, which I haven't heard for ages.
But then, on a quite different scale of length and emotional intensity, she is joined by Paul Lewis for a stunning performance of the Schubert Fantasie D940. And this is surely as good as it gets: two of the greatest Schubert pianists seemingly as one in their shared vision of the piece. Just wonderful.
February 19, 2011
Reading list on computable functions
At the moment, I'm going to Thomas Forster's Part III maths course on computable functions. I've put together an introductory reading list on the elementary stuff in the opening lectures, which may be of use/interest to others.
As usual, comments/corrections/suggested additions are always welcome — especially perhaps, in this case, pointers to particularly good online lecture notes, etc.
February 13, 2011
Another "last ever …" box ticked
There's no getting away from it: it does all feel slightly odd, as the academic year rattles on, being repeatedly struck by the thought "Well, this is the last time I'll be doing that." At the start of the year, the last time to be faced with another year of brand-new, eager-faced students at more or less their first university lecture; in December, my last first-year logic lecture; and now this last week, my last undergraduate class ever. (For USA readers: like all but a tiny handful, I have to retire from my post at the university's statutory retirement age.)
Will I miss undergrad. philosophy lecturing? Difficult to predict. But I think probably not. I might try offering a Part III maths course next year, if DPPMS will have me, but that's a quite different kettle of fish.
February 6, 2011
Brandom, continued
Let's add a further observation to what I was saying about Brandom in the last post. I said |- and |= (as defined) coincide in a classical framework. Now let |- be the usual consequence relation in an intuitionistic logic, and let |= be the derived consequence relation defined as described.
Suppose D + p is in Inc. Then, by definition, D + p |- q for any q, so we have, intuitionistically, D |- not-p. So inituitionistically again, D + not-not-p |- q for any q. That is to say D + not-not-p is in Inc. Hence, again by definition, not-not-p |= p (while of course we don't have not-not-p |- p). So here |- and |= peel apart.
I don't know whether there are cases of more impoverished frameworks which lack classical negation but where |- and |= do coincide. That's why I was asking about general conditions for getting the round-trip equivalence. But my conjecture is that the impoverished cases aren't going to be very interesting. (I'm encouraged in that thought by an email from Warren Goldfarb!)
Where does this leave us? It looks as though |- and |= typically peel apart, unless we are already assuming a classical framework (or something hobbled and uninteresting). So how could an inferentialist justify the claim that |= is the relation that matters (the one to feature in inferentialist definitions of connectives, etc.)? The suspicion must be that Brandom's very idea of starting from Inc and defining a consequence relation from it will just beg the question against e.g. the intuitionist. But is that right?
