Everything in miscellaneous

I think Weinberger is on to something, in his book 'Everything is miscellaneous'

I'm reading it at the moment - OK I'm always behind the times, but it was only published last year - and it is resonating with lots of things that I'm thinking about.

As always, there's lots more that I want to say about than I have time to do at the moment. For now, start with a quote from Chapter 9:

To know what a thing is, thought Aristotle, is to see what is essential about it [...] and not be fooled by just what happens to be true about it [...] The definitions of those essences determine those things that are in a category and those that are turned away. Here there is no messiness, only an order so precise and harmonious that it is beautiful.

Or so Aristotle and generations of thinkers assumed. So do we when we argue about, for example, how to define race, knowledge management, or blogging. But suppose this sort of Aristotelian categorization-through-definition were shown to be an essentially artificial way of approaching the world. Suppose messiness is not a flaw in our thinking but enables it.

I think there is a link here to Michael Frayn's "The Human Touch: Our Part in the Creation of a Universe". We create the universe by defining order. The order does not exist out there independent of us, waiting for us to find it. We make it.

EPR paradox

Here's my understanding of the paradox (the story I tell myself about it), and why in terms of information there's no problem.

(I'm writing this from memory, so it could be rubbish, but I think I have some of the essence in here. And it's not the original EPR - Einstein, Podolsky and Rosen - formulation, which I think was based on beta decay.) Imagine launching two entangled particles, say photons, heading off to two different locations. You take a measurement on one of them, say you test for spin up or down. The result of the measurement on one immediately tells you the result you'll get on taking the same measurement on the other. Eg, you measure photon A and find spin up, so you know measuring photon B will give you spin down. OK, no big deal so far. But, quantum mechanics tells you that photon A didn't decide it was going to be spin up until you measured it. So photon B has to be told, instantaneously, what photon A had decided to give as its result. Hence the need for instant communication (faster-than-light = violates causality, 'non-localisation')

But, as explained so far, it is pretty unconvicing to say that photon A didn't decide on what result it was going to give until it was measured. There's more to it. Instead of measuring for spin up or down, you could instead measure another parameter, say for spin rotation, clockwise or anticlockwise.* If you measure for spin rotation, then if A is clockwise B will measure anticlockwise and vice versa. But, if you measure for rotation then you lose coherence (is that how to express it?) for spin up or down. So, if you measure A for rotation, B can now be spin up or down with equal probablity. Likewise if you measure A for up or down, B can be closkwise or anticlockwise with equal probability. So now what is happening is that A 'tells' B whether you measured for rotation or up/down (as well as the result). Again, it has to happen instantaneously, hence the contradiction with relativity.

Experiments have been done, apparently, which test for this - the effect that measuring A influences the outcome of measurements on B. Now, I have not yet got an understanding of how these experiments are done. I'd love to know. But, my understanding of the conclusions of the experiments is:

- they have proved that there is an influence at a distance that happens faster than the speed of light
- but, you can not communicate information faster than the speed of light in this way

Now, here's my punchline: that final point somehow ruins it all! If you are not communicating information, then what's the big issue? Surely it is just like phase velocity in, say, waveguides? There's no problem at all with phase velocity exceeding c, because you can't carry information on the phase. It is the group velocity that matters.

Musical information - context again

Information/meaning doesn't only come from words?

I was listening to 'Private Passions' on Radio 3 at lunchtime today, and Martin Rowson, The Guardian's political cartoonist, was laying in to Bob Dylan, saying how useless he is as a poet. I like Dylan, though you can't argue that if you read the words as poetry disconnected from the music and the associations of the music, the zeitgeist, the context, if you read it like that, then it's not up there with the all-time great poetry. But, it wasn't written like that, it could not be written like that. The words, the music and the context are all of a piece.

This also links into the issue of information and meaning conveyed by music. In the discussions at an internal seminar exploring 'The Nature of Information' that we had at the OU last October, one of the contributors commented that we were only addressing information in words - written or spoken - and queried whether we should also consider our other senses, such as smell. This also links to elements in 'What good are the arts' by John Carey. But this is for another day.

Understanding understanding

What does it mean to understand something? Well, I think it means you can tell a convincing story about it.

Sometimes we talk about 'knowledge, skills and understanding' as the three aspects of learning. Knowledge and skills seem OK to me. Understanding is more problematic, yet in some ways seems the most important, the most fundamental. Knowledge: I know that flash memory is based on a MOSFET (metal-oxide-semiconductor field effect transistor) technology. Skills: I can do calculations on the capacity and speeds of flash memories. But, do I understand flash memory?

The first thing to say is that it is of course a continuum. I understand flash memory to some extent (like I know some things about flash memory and I can do some things relevant to flash memory). What makes me say I understand flash memory to some extent? Well, I can tell a story about what it is and how it works, and that story makes sense to me. That is, I can tell a convincing story about flash memory. Convincing to whom? I'm the one saying I understand it, so it is convincing to me. It may not be convincing to you, so you may say I don't understand it.

I'm writing about flash memory for T325 ("Technologies for digital media" - a new OU course for 2009), so I'm telling a story about it in the course text. We want students to understand it, and we'll be asking questions to check whether they do. They'll need to tell a story back to us to convince us that they understand.

That's the story I tell about understanding anyway.