Available Light

Monday. It's my day off. I lay in bed for longer than usual, until almost 7:00 am and watched an interesting little film on my phone. It was an Aeon magazine piece about a guy burning a stack of mouldering Encyclopaedias . He talks about the way the possession of knowledge has changed; once knowing stuff was the preserve of the moneyed elite and now it is accessible to all, for good or ill. It was a beautiful Dunedin day when I finally got up. In the middle of the morning I drove the Portobello road with my second best camera and took a few pictures It was one of those days when I know without a shadow of doubt that Dunedin is the most beautiful city in the most beautiful country in the world. The air was crisp and the low sun provided sharp edged clear light. It was impossible not to feel blessed. I drove a comfortable, powerful well equipped car on a delightfully twisting road. I listened to Palestrina's Missa Papae (I'm willing to believe there is mus...

Galileo got into trouble in 1632 for writing a book which a) insulted the Pope and b) suggested that the Sun, and not the Earth was the centre of the universe. He was  sort of right about both points, but not everyone saw it that way, especially the Pope, and Galileo ended up spending the rest of his life under house arrest. Galileo's problem was that the theory he was propounding, heliocentrism, seriously undermined the status quo and ran counter to common sense (everybody could see that the sun was smaller than the earth and rose on one side of the world, set on the other, and presumably nipped around the back during the night). Further, Galileo's theory depended on some rather arcane mathematics which very, very few people could understand. Those who could understand the maths, and this group included the guys who advised the Pope, could see something else: that  Galileo's sums did not quite stack up.Galileo believed that the earth and other planets moved in perfect circ...

 Lately I have been thinking about Frank Jackson's thought experiment, variously called Mary the super-scientist or Mary's Room . I have even preached about it a couple of times, and a recording of the last time, at St. Matthew's Dunedin, is here . The thought experiment goes something like this: Mary is the world's most brilliant neurophysiologist. her specialty is the perception of colour. She knows absolutely everything there is to know about colour: how the retina is affected by light, how the brain processes the information etc. When it comes to colour perception,  there is not one fact that it is possible to know that she does not know. By a huge irony, however, Mary is herself only able to see monochromatically. That is, though she knows all it is possible to know about colour, she has never experienced colour vision herself. One day, due to some freak happenstance,  her monochromatism is ended, and she is able to see colours. The question is: does she know a...