absolutely nothing

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I few days I was reading from George Perec’s Species of Spaces and Other Places1, or rather reading is not quite the right word, Perec is an odd writer and the book is more something to dip into than to read in any concerted fashion.

Perec is writing about spaces without function and says:

How does one think of nothing? How to think of nothing without automatically putting something round that nothing, so turning it into a hole, into which one will hasten to put something, an activity, a function, a destiby, a gaze, a need, a lack, a surplus …?

This reminded me of another book, Edward Casey’s The Fate of Place2. Casey surveys various creation myths and finds that while at forst glance many seem to have a creation ex nihilo, in all cases the emptiness, the void is not so empty, either bounded, or filled with chaotic churning, unformed things. There is no empty space.

These myths are about the feelings and conceptions of people and tell us somehting deep about our inability to capture an essence of nothingness, just as Perec struggles. The concept of the number zero eluded (or appalled) the Greeks and the idea of the empty set causes problems for many students, perhaps only made palitable by the curly brackets surrounding the emptiness {} … “putting something round that nothing“.

They say “nature abhors a vaccum”, although I guess one wonders whether it is just people who abhor it. One of the surest forms of torture is sensory deprivation.

The role of the void in physics has changed over the years. From being simply the empty gap between things. 19th century scientists populated it with electromagnetic and gravitational fields – the void became the medium, a material internet through which forces rippled.

In Einstein’s General Relativity, space is no longer the medium through which gravity is transmitted, but instead it is the distortions of space-time that define matter itself. Space is not filled with other things, it is the things.

However, in Quantum Mechanics we find a world that is rather like the voids of those reation myths, empty space forever filled with zero-point energy. And in the emptiness particles and anti-particles constantly appearing and anihilating one another; a boiling broth not still waters.

Most strange, when empty space is bounded, the very walls are sucked in by an extra emptiness. The bundaries mean that certain modes of vibration of the space between the walls are not possible – like a guitar string that will only play certain harmonics – and those missing vibrations cause missing energy.

So, when Perec puts “something round that nothing” he in fact makes it less than it was before.

  1. George Perec, Species of Spaces and Other Places , (tr. John Sturrock), Penguin, 1997. ISBN 0-14-018986[back]
  2. Edward Casey, The Fate of Place: A Philosophical History, University of California Press, 1998. ISBN 0-520-21649-0[back]

the power of sequential thinking

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A short while ago I was mentioning to another computing academic at a meeting the curious fact that the computational power of the complete internet is now roughly similar to that of a single human brain [[see article here]]. While this little factoid is deliberatly provocative, I did not expect the strength of the response.

“that’s impossible” he said.

“why” I asked, “I’m not saying they are similar, just that there is the same computational potential”

“Computers are sequential” he said, “brains are associative”.

Further attempts to reason, likening it to other forms of simulation or emulation, simply met with the same flat response, a complete unwillingness to entertain the concept.

Partly this is to do with the feeling that this somehow diminishes us as people, what for me was a form of play with numbers, for him was perhaps an assault on his integrity as a human. I guess as a Christian I’m used to the idea that the importance of a person is not that we are clever or anything else, but that we are loved and chosen. So, I guess, for me this is less of an insult to my idea of being who I am.

This aside it is interesting that the reason given was about the mode of computation: “computers are sequential” vs. the massively parallel associativity of the human brain.

Of course if the computational substrate is all the PCs connected to the Intenet then this is hardly purely sequential and in fact one of the reasons that you could not ‘run’ a brain simulation on the Internet is that communication is too slow. Distributed computation over 100s of millions of PCs on the internet could not synchronise in the way that long-range synapses do within our brains.

Amongst other things it is suggested that our sense of consciousness is connected with the single track of synchronised activity enabled by the tight interconnections and rapid feedback loops within our brains1. In contrast, individual computers connected to the onternet compute far faster than they can communicate, there could be not single thread of attention switching at the rate that our minds can.

If the internet were to think it would be schizophrenic.

Sequence is also imprtant in other ways. As the man said, our brians are associative. When considering spreading activation mechanisms for intelligent internet interfaces, one of the problems is that associative stuff gets ‘mixed up’. If London has a high level of activation, why is that? In a designed computational framework it is possible to consider mutiple ‘flavours’ of activations spreading through a network of concepts, but our brains do not do this, so how do they mange to separate things.

Now to some extent they don’t – we get an overall feel for things, not seeing the world as little pieces. However, it is also important to be able to more or less accurately ascribe feelings and associations to things. Consider one of those FBI training ranges were bank terrorists and hostages pop out from behind windows or doors. Your aim is to shoot the terrorists and save the hostages. But, if you see a robber holding a hostage how do you manage to separate the ‘bad and kill’ feelings and properly ascribe them only to the terrorist and not the hostage.

The answer may well be due exactly to the switching of attention. Even with both terrorist and hostage are next to each other, as mental attention shifts momentarily to one and then the other, the mental associations also shift. Rodney Cotterill in Enchanted Looms describes two levels of attention switich2. One near conscious and taking around 500ms and one connected with more low-level visual attention (sometimes called a visual searchlight) at 20-50ms. It is probably the slower timescales that allow fuller webs of association to build and decay, but maybe there are other intermediate timescales of attention switching as well.

If this is right then the rapid sequential shifts of attention could be essential for maintaining the individual identity of percepts and concepts.

If we look at concepts on their own, another story of sequence unfolds.

There is a bit of a joke among neuroscientists about grandmother cells. This is the idea that there is a single neuron that in someway encodes or represents your grandmother3

Looking at this purely from a computing science perspective, even if there were not neurological reasons for looking for more distrubuted representations, there are computational ones. If concepts were stored in small local assemblies of neurons (not single ones to allow some redundancy and robsutness) and even a reasonably large part of our brains were dedicated to concept memory, then there just seems too few ‘concept-slots’.

If we used 100 neurons per concept and 10% of the brain for concept memory, we would only have space for around 10 million concepts. A quick scan through the dictionary suggests I have a reconition vocabuary of arounf 35,000 words, so that means I’d have less than 300 other concepts per dictinary word one. Taking into account memories of various kinds, it justs seems a little small. If we take into account the interconnections then we have plenty of potential long-term storage capacity (1/2 petabyte or so), but not if we try to use indiviudal groups of neorons to represent things. Gradmother cells are simpy an inefficient use of neurons!

Now there is also plenty of neurological evidence for more distributed storage. Walter Freeman describes how he and his team lovingly chopped the tops off rabbits’ skulls, embeded electrodes into their olfactory bulbs and then gently nursed them back to health4. The rabbits were then presented with different smells and each smell produced a distinctive pattern of neuron firings, but these patterns exteded across the bulb, not localised to a few neurons.

If neurons had ‘continuous’ levels of activation it would be possible to represent things like “1/2 think it is a dog 1/2 think it is a fox”, simply as an overlay of the activation of each. However, if this were the case, and one could have in mind any blend of concepts, then an assembly of N neurons would still only be able to encode up to N concepts as the concepts patterns would form a set of basis vectors for the N-dimensional vector space of possible activation levels (a bit of standard linear algebra).

In fact, neurons tend to behave non-linearly and in many areas there are patterns of inhibition as well as mutual excitement and disinhibition, leading to winner-takes-all effects. If this is true of the places where we represent concepts for short term memory, conscious attention, etc., then this means instead of representations that ‘add up’, we have each pattern potentially completely different, similar to the way binary numers are encoded in computer memory: 1010 is not a combination of 1000 and 0010 but completely different.

In principle this kind of representation allows 2^N (two to the power of N) rather than N different concepts using the same N neurons … In reality, almost certainly representations are less ‘precise’ allowing some levels of similarity in representations etc., so the real story will be more complex, but the basic principle holds that combinations of thresholding and winner-takes-all allow more distinct concepts than would be possible if combinations of concepts can occur more freely.

However, notice again that higher capacity to deal with more concepts is potentially bought at the cost of being able to think of less things ‘at once’ – and the side effect is that we have to serialise.

Returning back to the “computers are sequential, brains are associative” argument, whilst not denying the incredible parallel associativity of human memory, actually there seems as much to wonder about in the mechanisms that the brain ‘uses’ for sequentiality and the gains it gets because of this.

  1. see Gerald Edelman, Wider then the Sky, Yale University Press, 2004, ISBN 0-300-10229-1[back]
  2. Rodney Cotterill, Enchanted Looms: Conscious Networks in Brains and Computers, Cambridge University Press, 1998, ISBN 0-521-62435-5. See p. 244 for 500ms switching and pp. 261 and 265 for 20-50ms spotlight/searchlight of attention[back]
  3. Although the grandmother cell this is generally derided as oversimplisitic, there is evidence that there is more neuron specialisation then previously thought [[see Mind Hacks: evidence for ‘Grandmother Cells’]]. Also it is easier to encode relationships if there are single patches than configuratiin sof neurons, so perhaps we have both mechanisms at work.[back]
  4. Walter J. Freeman, How Brains Make Up Their Minds, Phoenix, 1999, ISBN 0-75381-068-9. See p. 95 onwards for rabbit olfactory bulb experiments.[back]

paying the tax

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tax collectors get a bad press, but we have just got to the end of filling in our annual tax returns online and is an amazingly trouble free process … I can still remember when it was paper forms and 2 days before the final deadline we’d discover we needed extra green pages for this thing or other. Now-a-days you just fill in the boxes on the web form, if you haven’t got the figures it just remembers it all for later, then at the end you press the button and it works out everything. And even better, they said they owed me £80 🙂

If only every online service was as good. A short while ago we tried to open a savings account with the Northern Rock and gave up as the applet-based system they use is not compatable with Apple Macs … other banks seem to be able to use SSL for security and browser-independent HTML, so why not them! Suffice to say we went elsewhere.

Even worse was an experience early last year. I’d given a seminar at another university and submitted an expense claim. The university sent me payment advice as an email, but it displayed oddly when I viewed it and got a high spamassassin rating. A bit of digging and I found that the high spam rating was due to the fact that there was not a closing body tag in the HTML. I was going to mail the university IT support and then saw that the company who supplied the software, Albany Software, was named in the email and decided to mail them directly to avoid embarassing them to their client.

So I went to their web site … but it didn’t display properly in Firefox, I tried Safari … even worse! Eventually I got their ‘support’ contact email by using view source and mailed them, mentioning both the broken HTML in the email and the broken website.

The reply from their ‘support’ email:

“Try using Microsoft Internet Explorer. Though Firefox is vastely superior, most websites/applications are only compatible with Internet Explorer.”

Who said the days of the old sys admins had gone!

The happy end to the last story is that I just revisited their site, they have at last got it working cross browser … well I guess better late than never.

Anyway thumbs up for Her Majesty’s Revenue & Customs, even if others need to catch up a little.

politics of water – trouble in paradise

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Today I got a mailed posting from Geoff Ellis who is visiting family in Mauritius (see copy at end of this entry)

Water politics is on the rise both because of climate change and competition for the use of rivers that cross borders. Recently I heard that the Dead Sea is drying up, although evidently the Aral Sea may be slowly recovering.

However, this also reminded me how as a child the Free Wales Army were my heroes. I was to small to understand much about it, but I do know they blew up water pipelines. Sadly (so I thought) they were eventually captured and put behind bars and the water pipelines were safe. Now I guess these were acts of sabotage rather than terrorism and in retrospect it sounds rather ridiculous … blowing up oil pipelines, yes, but water?

Being brought up with Cardiff they seemed sort of Welsh Robin Hood-like figures – very romantic.
It was only years later I understood the full story.

When I was nine years old my dad died and after that we lived on a state widows pension supplemented with students (and at one stage Irish navvies) staying half-board. Hard work – hot meals to prepare breakfast and evening, washing, not to mention cleaning the thick orange Cardiff clay from the carpets when the navvies were staying.

Once a year we got the bill for the water rates. There was also a once-a-year bill for the house rates (tax on land/housing), but as we were on low income we got 90% rebate for this, so it was not too bad. But when the water rates came, there was no rebate, and that stage not even monthly payments to spead the cost. Mum was good with money, budgeting carefully and saving for major bills, but still it was a big bill and hard to pay on one go … and for this water tax there was no relief or rebate, no matter your income, you had to pay in full.

It was then years later again and I was renting my own hose for the first time in Bedfordshire … England. When I got my first water rates it was for £60 (it was a few years ago!) and when I asked mum I found hers was for £300. The population in Wales is very spread out, so it is more expensive to transport the water, and hence, I guess, why it cost five times as much.

If Wales has a national resource (once the coal was plundered), it is water … it rains, and rains, and rains! When I was little my dad used to drive us up to visit Brecon, through the coal valleys north of Cardiff and up into the Brecon Beacons, with the vast reservoirs filling the valleys between the mountains. We picnicked beside the streams flowing down the mountains and wondered at the huge dams.

The water from these dams does not flow to Cardiff, the coal valleys or central Wales, but is piped to Birmingham … and as the water flows out, no money flows back. So English water is cheap, and the cost of Welsh water falls heavily on those who can afford it least.

The Free Wales Army deserve a play or a film, a slightly askance view … you cannot present blowing up water pipleines with a straight face, but with a hint of the issue beneath. For me as a child, the politics of water was a painful and serious business.
Geoff’s posting from Mauritius:

water trouble in paradise

L’Avenir, St. Pierre, Mauritius 31 Dec 2006

In this usually quite village of L’Avenir nestled amongst the mountains on the Mauritian plateau, New Years eve is a time for cleaning the house ready to welcome the New Year with fireworks. But this year is different. The road is ablaze at both ends of the village as some of the residents, frustrated by days of water cuts, have taken to Royal Road. They just haven’t run out of water, in the higher parts of the village for 5 days now, some have run out of clean clothes to wear. It is true that the reservoirs are lower this year due to less rainfall than usual over the winter months, but what makes the residents angry is the seemingly unjust way in which the limited water is supplied. In the neighbouring village of Beau Bois they have water and in the small town of St. Pierre a mile away I’ve seen people washing the pavements in front of their houses, no sign of water shortage there. And of course, the hotel swimming pools are full, the greens and fairways of the golf course are lush and I doubt if any ministers or government officials have been washing in a bucket! As one residents told me, making a civil disturbance in the only way to get the water turned back on, no one answers the water board office ‘hotline’ . Whether or not we will be able to wash in 2007 is somewhat in the hands of the gods.

Geoffrey Ellis (UK resident on holiday in L’Avenir with parents-in-law)

fire in the streets in Avenir
[see full image]

Saddam’s execution

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The images of Saddam Hussein’s execution filled the newspapers this morning as they filled the TV news yesterday. Sadly the manner of the trial and execution seem to have transformed a ruthess dictator into a folk hero.

His execution now robs those who have had loved ones die in other mass executions during Saddam’s rule from knowing the truth. And moreover lets those in the West implicated in many of them off the hook.

I recall during the Iran-Iraq war, the reports in that clarion of left wing journalism, the Reader’s Digest, of the use of chemical weapons against civilian Kurds. Everyone knew about it, except the governments of the West for whom Saddam was an ally against Iran and the Kurds an inconvenince – friends of Iran and troublesome in Turkey. No justice for these families.

And why no trial for the massacres in the South following the Gulf War? Perhaps fear that it would bring back to mind the way we encouraged ethnic civil war in the hope it would topple Saddam without dirtying our own hands.

The hypocracy of the ‘diplomacy’ of the late 20th and early 21st century is sickening. In Iraq as in Yugoslavia, we sow the seeds of ethnic strife and then throw up our hands in horror at the results.

“first take the plank out of your own eye, and then you will see clearly to remove the speck from your brother’s eye“

of monkeys and men

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In my friend Nadeem’s blog he asks why can’t a woman be more like a man?

well Nad, I should explain, there is a biological basis for this 😉

you will have often have seen remarks by geneticists that say we human beings share 99% of our genes with monkeys.

now also you know that in a man there is that vital Y chromosome that is totally unlike anything in a female cell

well we have 46 chromosomes, so that vital difference means that just over 2% of our genetic makeup is totally different from a woman – we share less than 98% of our genes with women

in other words men are genetically more similar to monkeys than women

and so here is a picture of my favourite monkey:

my monkey at the computer

Dennett’s Sweet Dreams – consciousness and the Turing test

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I read Dennett’s Sweet Dreams a few months ago. Although I am also interested in dreams this book is about consciousness … indeed subtitled “Philosophical Obstacles to a Science of Consciousness”

The book is largely about one message – that a scientific study of consiousness can only take into account third party accessible knowledge about first part experience. In other words I can only base a scientific study on what I can tell of other people’s consciousness from their actions, words and any available brain scanning etc.

Dennett has a meticulous rhetoric, but I found two broad facets of his argument weak, one more about rheteric and one substance.

First somewhat disingenuously he does not say that a scientific study of consciousness would yield a complete account of consciouness, but effectively the implication is there. That is he does not say that consciouness is no more than its phenomenial effects … but implies it.

Second, being a philosopher he focuses on incontrovertible evidence, whereas as scientists and humans often reasonable evidence is sufficient.

The first point is obvious and yet easily underestimated. A ‘scientific’ study of literature could formulate many known literary rules (aliteration, rhyme, etc.) and may even find new ones, and indeed poets in particular are happy to perform such analyses. However, we do not expect such rules to be a complete account of literture.

The second point is more substantive, but does interact with the first.
Dennett takes issue with philosophers who posit some form of non-sentient zombie (often called ‘Mary’) who/which nonetheless behaves otherwise exactly like a human including things that might appear to be conscious. They then say “but of course Mary is not conscious”. Dennett objects to the ‘of course’, which is really a statement about prior beliefs/assumptions (although Dennett, of course, frequently does the same with his beliefs!).

Dennett posits a Robo-Mary which is entirely mechanical/electronic and yet emulates perfectly the brain circuitry of a person and so can work out how the person would react and then reacts similarly. From the outside and by all her (emulated) subjective reactions she appears to be conscious. She would pass any ‘Turing Test’ for consciousness and yet many, perhaps most, would say she is not. The implication (from the first weakness) is that we are no more conscius than she (it?).

Actually I don’t object to the idea that such a creature may indeed be conscious, but I’d need more evidence than I would for a human, not because Robo-Mary is a machine, but becasue she is designed to appear conscious.

Robo-Mary is in fact a Robo-Mata-Hari, a spy, a robot in human clothing.

A good enough actor may convince you he is feeling happy, sad, or in love, and you may not be able to tell the differece between the act and the real thing, but that does not mean happiness, saddness and love are no more than their appearance.

As a philosopher, you cannot have incontrovertible evidence that a person’s emotions are real, not just a facade. However, as a human it would be unreasonable to therefore dismiss all expressions of emotion.

Some (well many) years ago, I worked with people at York who creating one of the first ADA compilers. There was a validation suite of programs that had to compile and run correctly for the compiler to get an official stamp from the ADA standards agency. I used to wonder about writing a program that recognised each of the tests cases and simply spat out the right code for each one. Any other program given to the program would simply print an error message and stop. The program would pass the test suite and could get the stamp as being a validated compiler, and yet would be completely useless. It would be a cheat ADA compiler.

Imagine if I sold such a cheat compiler. Any judge would regard it as fraud – whilst it passed the test, it is clearly not an ADA compiler. The test is there to validate things that are designed to be ADA compilers, not things designed to pass the test. So, the cheat ADA compiler is not adequately validated by the test, just becase it is designed to pass it.

Robo-Mary is designed to pass the consciousness test … indeed any consciousness test. We perhaps could never incontrovertibly tell whether Robo-Mary was conscious or simply acting conscious. However, when faced with another human being, an ordinary Mary, who is not designed specifically to appear conscious, it is reasonable to assume that she experiences similar things to me when she describes her experience in similar terms. I can never incontrovertibly tell that Mary is conscious, but it is reasonable to believe so. And it is equally reasonable to base a scientific study on such defeasible observations.

Turning back to Robo-Mary; convincing machine cosciousness would not come from machines designed to appear conscious, but more ‘by accident’. Perhaps one day my intelligent automated vacuum cleaner will say to me “Alan, have you ever watched those dust motes in the sunlight”.