Mostly Harmless Science Blog

Red Mars, p.211

noreply@blogger.com (Chris Fellows) — Fri, 13 Nov 2009 20:28:00 +0000

On re-reading Red Mars after more than a decade, I have been struck with how strongly 'red' my sympathies are. I don't remember feeling strongly one way or another when I first read the book. Now the prevailing mood among the first hundred Martians to begin terraforming immediately seems appallingly reckless to me, and I find myself in complete agreement with Ann Claiborne:

'Here you sit in your little holes running your little experiments, making things like kids with a chemistry set in the basement, while the whole time an entire world sits outside your door. A world where the landforms are a hundred times larger than their equivalents on Earth, and a thousand times older, with evidence concerning the beginning of the solar system scattered all over, as well as the whole history of the planet, scarcely changed in the last billion years. And you're going to wreck it all. And without ever honestly admitting what you're doing, either. Because we could live here and study the planet without changing it - we could do that with very little harm or even inconvenience to ourselves. All this talk of radiation is bullshit and you know it. There's simply not a high enough level to justify this mass alteration of the environment. You want to do that because you think you can. You want to try it out and see- as if this were some big sandbox for you to build castles in. A big Mars jar! You find your justifications where you can, but it's bad faith, and its not science.'

On page 173, the explorers find it 'startling in the extreme' to run across the tongue of a glacier, looking like a big white Uluru, even though they knew it would be there. I'm afraid they won't find anything startling, because they will have Google Mars.

Dunes in the Vastitas Borealis - let's not drown them just yet!

Of course, there isn't nearly enough water to do so- only 820,000 km³ or so.

Some changes we've made to the surface of Mars already- rover tracks on the edge of Victoria Crater:

Happy Happy Joy Joy

noreply@blogger.com (Chris Fellows) — Thu, 12 Nov 2009 12:21:00 +0000

Just thought I should say something about Peter Garrett blocking the Traveston Dam. This is a good, good, good, good thing. The Australian Lungfish is a species of global importance that we have a duty to look after. We make do at my place with the water that falls on our house and shed, and all those people in Southeast Queensland ought to do the same. Plants that won't thrive on rainwater have no place in Australian gardens.

Anyway, if Queenslanders want to be profligate, we have plenty of perfectly fine rivers in Northern New South Wales that we could dam to collect water to sell them...

Glass half full...

noreply@blogger.com (Chris Fellows) — Tue, 10 Nov 2009 04:19:00 +0000

The system for electronic submission and return of assignments that came in this year is beset with all the usual follies and aggravations of new technology, but I have just made a jpeg to use in marking assignments that I am looking forward to using:

On trying to read Schopenhauer

noreply@blogger.com (Chris Fellows) — Sat, 07 Nov 2009 03:04:00 +0000

Earlier this year Klaus Rohde made a number of posts about the ideas of Schopenhauer, the famous philosopher. I read one of the essays Klaus recommended on Schopenhauer’s thought and wrote a response to it.

I also read a book of extracts from Schopenhauer's ‘Parerga and Paralipomena’ in English and wrote two documents outlining some of the places where I agreed with what Schopenhauer said in the extracts, and some of the places where I disagreed with him.

But Schopenhauer wrote a magnum opus- practically the archetype of the magnum opus- outlining his mature thought, ‘The World as Will and Appearance’, which takes up three volumes in our library, and to argue about what he thought without reading it is really very lazy. So I thought I would have a go. I got out volume one, skipped the preface, and started wading in.

Unfortunately I did not get very far. And oddly enough I got hung up at the same point that a friend of mine got hung up on at the onset of ‘Mere Christianity’, by C. S. Lewis, when I lent it to him as an undergraduate. I rejected Schopenhauer’s initial argument, the foundation of the whole three volumes. The ‘oddly enough’ is because it was the identical initial argument of ‘Mere Christianity’- the assertion that consciousness is inexplicable by materialism. Lewis argues that consciousness is an irruption of the supernatural other into the natural universe, and from that goes on the derive Christianity; Schopenhauer argues that consciousness is the fundamental fact of the universe, the ultimate reality that generates the world of appearances around us, and that data from that world of appearances cannot explain consciousness.

I reject solipsism- the argument that the only data point I have is my own consciousness, therefore only I exist- because it is fruitless; you can’t do anything with it. It is an idea that leads nowhere and achieves nothing.

The idea that consciousness in general, as opposed to ‘my consciousness’ is the fundamental fact of the universe requires the existence of other minds.

How do we know these other minds exist? By observations we make of the world of appearances. So we must base our understanding of mind in general not only on the one data point we truly have access to, inside our own heads, but on how we observe mind to be manifested in space and time within this world of appearances. I think we cannot do this and fail to observe that mind is an emergent property. There is no sudden transition from things that are conscious to things that are not. We see insects displaying apparently conscious behaviour that we can model with a simple circuit. As we traverse the angora shawl of being*, more and more complex organisms display more and more complex behaviours, which we can explain more and more tentatively in terms of mechanistic inputs producing certain outputs. Eventually we get to us. Made out of the same kind of stuff, with a nervous system obviously just a more complicated version of the same nervous system the bugs have.

I think consciousness is just what a system of registering and reacting to sense impressions looks like from inside. A simple system, where we can see and understand that it is completely deterministic, might still feel like something from the inside. It might feel, to the moth, as if it chooses to dive toward the light.

It feels to me that I am composed of sense impressions and memories of sense impressions, and that there is nothing else. This no longer bothers me. (Of course you can come back and say: ‘Who is this ‘me’ who is feeling, Chris? Who is this ‘me’ who is no longer bothered?’ But this I will reject as mere semantic gymnastics, arguing about words rather than things.)

So I reject Schopenhauer’s fundamental division of the world into Mind and Matter. Solipsism is not rendered less vacuous and fruitless if Will, some fundamental thing underlying all consciousness, replaces my individual consciousness.

I went back some months later and had another go at ‘The World as Will and Appearance’. This time, I tried to do things properly and started with the preface. It reminded my strongly of the pretentious author’s note quoted in ‘Ghastly Beyond Belief’”:

Author's note: It is suggested that the reader not attempt to read this book at one sitting. The intellectual content of these stories, taken without break, may cause brain damage. This note is intended most sincerely, and not as hyperbole.

ARTHUR BYRON COVER, The Platypus of Doom and Other Nihilists

Really. Schopenhauer says that the entire book of ‘The World as Will and Appearance’ was the shortest way he could find to write what he wanted to say, that it was impossible to summarise, and that I would have to read the whole thing to grasp his idea. Now, I am not of the opinion that every idea can be squeezed into a thirty-second soundbite, but this seems to me just a teensy bit ridiculous. All the really big ideas that really are ideas can be squeezed down into something small enough for us to get our heads around. This does not mean that there are not lifetimes of work in unpacking everything that is involved with and implied by

‘It is impossible to convert heat completely into work in a cyclic process.’

Or

‘Do unto others as you would have them do unto you’

Or

‘The square on the hypotenuse is equal to the sum of the squares on the other two sides’

…but all these really big ideas can be expressed in a few little words. Claiming that your idea is bigger than all these ideas is up there on the angora shawl of pretentiousness with Mr Cover and his Platypus of Doom.

The other thing Schopenhauer told me in the preface was that ‘The World as Will and Appearance’ was intended as an extended gloss on his earlier essay, ‘On the Fourfold Root of the Principle of Sufficient Reason’, and should be read in conjunction with it, and that it was useless- Useless, I tell you! – to read his magnum opus without having first read ‘On the Fourfold Root of the Principle of Sufficient Reason’. I dutifully went back to the library to find it. But it was not there.

Right next to the works of Schopenhauer that were on the shelf was a slim book by Schrödinger, ‘My View of the World’. I took it home as a consolation prize.

Curiously, I found that it was not only next to Schopenhauer in alphabetical space, but in idea space. It contained what appeared to me to be practically the same Vedic philosophy of the primacy of mind.

He says, in a fine and honest way in his opening remarks, that there is very little about physics in his book, and that is because he came to his ideas about the nature of reality before he ever got into quantum mechanics: he was already marinated in the same ancient Hindu ideas that Schopenhauer had discovered and embraced so enthusiastically. I have taken the book back to the library already, so I can’t quote you the quote I wanted to quote you, but Wikipedia tells me: ‘At an early age, Schrödinger was strongly influenced by Schopenhauer. As a result of his extensive reading of Schopenhauer's works, he became deeply interested throughout his life in color theory, philosophy, perception, and eastern religion, especially Vedanta.’

Schrödinger did not ‘discover’ all the New Agey hippy-dippiness in Quantum Mechanics; he brought it with him. It was part of his worldview while he was figuring things out about the world of appearances, and he fit them in where they fit in his personal philosophy - and there we have one root of the muddle we are in now.

So I still have not read Schopenhauer’s Magnum Opus. Which is sad, since as Schrödinger says in a possibly apocryphal quote I found on the web just now: ‘If you cannot - in the long run - tell everyone what you have been doing, your doing has been worthless.’ I have not given up. But I have gathered enough, I think, to sum up my disagreement with Schopenhauer in a table contrasting him with the most useful and clear-headed philosopher since Aristotle and my personal favourite, 'the one American philosopher that could sing outdoors', Charles Sanders Peirce**:

*: This is my ad hoc replacement for the ‘chain’ or ‘ladder’ of being, which is what I really want to say, but which I am too conditioned by my reading of Stephen Jay Gould to dream of saying.

**: I have doctored this Hilaire Belloc poem to show you how to pronounce his name, in case you don't know:

Once more with the splendour of the historical sciences!

noreply@blogger.com (Chris Fellows) — Fri, 06 Nov 2009 03:02:00 +0000

Last week or the week before I went to the niftiest seminar I have been to for a long time. It was by Prof Ian Metcalfe, who is a master of conodont lore- conodonts being the premier biostratigraphic animal. If you know enough about conodonts, and you are lucky enough to find enough conodonts, you can tell when a stratum of rock was laid down and what biogeographic province it belonged to, over a vast range of space and time. And the degree of detail that is possible with these little guys was enough for Prof Metcalfe to deconvolute the whole extraordinarily complex geological history of Southeast Asia, which is basically a matter of bits breaking of of Gondwanaland and different times and sailing away north and mashing into the ancient subcontinents of Siberia and Kazakhstan.

I remember one thing that struck me forcefully, long ago, in the writings of Stephen Jay Gould, was all the ancient oceans that we would never know anything about, because they were subducted away completely- all those primordial analogues of the Hawaiian islands, with their unique fauna and flora, irrevocably lost.

But not always! That was the most impressive bit of Prof Metcalfe's talk for me. I have pinched one of his figures so I can show you, as like me you are probably too lazy to follow the link.

In between the dark orange Sibumasu block that used to be part of the Cimmerian Continent and the pink bit that is the mashed remains of the ancient archipelago of Cathaysialand, there runs an ancient biogeographic divide: at the same time in prehistory, the fauna on one side was quite different from the fauna on the other side. And mashed up in between those two blocks are sediments that are the remains of the Palaeo-Tethys ocean. Not all subducted away! Some of it is still there, enough of the ocean for us to tell a lot about its history and the sort of things that lived there, in a kind of Reader's Digest condensed version squashed into a discontinuous squiggle across central Thailand. I think that is so cool...

Could be a coincidence...

noreply@blogger.com (Chris Fellows) — Sun, 01 Nov 2009 21:36:00 +0000

There are, after all, only about 200 gazillion Facebook users, and the name might be as common in Chennai as 'Kylie Smith'. But I have deactivated my Facebook account (not in my real name, 'Wayne' and 'Nick'! :p ) anyway. Since otherwise to make that 'friend suggestion' Facebook would have had to have found out who I really am from my email address, then collected earlier email addresses belonging to me, and looked up users whose names appeared in lists with those earlier email addresses. Probably a long bow to draw. Such omnipotent data-trawling AI's probably have less frivolous things to do. More likely a coincidence. Freaky anyway.

My brother is participating in Movember, I am sure he would be pleased if you clicked the link and made a donation. I am too far gone, as you probably know, and am now only eligible for 'Look-like-the-unabomber-ovember'...

Think. Quantitatively.

noreply@blogger.com (Chris Fellows) — Tue, 06 Oct 2009 08:50:00 +0000

Every year I tell my students something like: ‘When you finish any calculation in physical chemistry, have a look at the number you have ended up with and see if it is a reasonable number. Is it about the size you would expect? If it isn’t, go back and find the mistake. If you are in an exam and pressed for time, write: ‘I know this number is the wrong size, but I can’t find where I went wrong.’ Or, just change the order of magnitude to the order of magnitude it ought to be, and hope I don’t read your working carefully.’

Every year, I get more cautionary tales to tell my students when I tell them this- assignments I have received with chemical bonds blithely reported as longer than the distance from here to Alpha Centauri, molecules heavier than the Sun, energies for chemical reactions greater than the annual output of all the power plants in Europe.

The chapter ‘The Spur of the Moment’ is about a project to build a sea in Hellas Planitia in the southern hemisphere of Mars, a sea that is quoted as being ‘1000 by 300 km’. It order to give the project verisimilitude, numbers for amounts of water are quoted throughout the chapter.

p.400:

It was a running river, in an obviously riverine valley, placid in some places, agitated in others, with gravel fords, sandbars, braided sections, crumbling lemniscate islands, there a big deep lazy oxbow, frequent rapids, and far upstream, a couple of small falls. Under the tallest waterfall they could see the pink foam turn almost white, and patches of white were then carried downstream, to catch on boulders and snags sticking out from the bank.

‘Dao River,’ Diana said. ‘Also called the Ruby River by the people who live there.’

‘How many are there?’

‘A few thousand. … Upstream there are family homesteads and the like. And of course then the aquifer station at the head of the canyon, where a few hundred of them work.’

‘It’s one of the biggest aquifers?’

‘Yes. About three million cubic metres of water. So we’re pumping it out at a flow rate- well, you see it there. About a hundred thousand cubic metres a year.’

10⁵ m³ per year = 274 m³ per day = 3 litres per second

To put this number in perspective:
“Older firehoses with 2.5 inch diameter equipped with a 1.5 inch nozzle can typically deliver 20-40 litres of water per second” (Physics of Continuous Matter: Exotic and Everyday Phenomena in the Macroscopic World, Benny Lautrup)

I suppose the description of the river *could* apply to something that one could easily step over, but I do not think this was the author’s intention.

p.416

One day at the office, news came in from the Hellespontus. They had discovered a new aquifer, very deep compared to the others, very far away from the basin, and very big. Diana speculated that earlier glacial ages had run west off the Hellespontus range, and come to rest out there, underground- some twelve million cubic meters, more than any other aquifer, raising the amount of located water from 80 % to 120% of the amount needed to fill the basin to the -1-kilometer contour.

Let’s see, the Hellas Planitia basin is quoted as being 1000 by 300 km. That’s an area of 10⁶ m × 3 × 10⁵ m, or 300 billion square metres.

Twelve million cubic metres would cover 300 billion square metres to a depth of

1.2 × 10⁷ m³ / 3 × 10¹¹ m²

= 4 × 10^-5 m.

40 microns.

So if this raises the amount of located water from 80 % to 120 %, at a first approximation the Hellas Sea will be 0.12 mm deep.

I confess myself unimpressed by this feat of areological engineering.

I expect KSR made the common undergraduate mistake of assuming
1000 cubic metres = 1 cubic kilometre. I wonder if the numbers have been corrected in later printings?

Green Mars, p.346

noreply@blogger.com (Chris Fellows) — Wed, 30 Sep 2009 10:59:00 +0000

My favourite bit so far has been the chapter 'The Scientist as Hero'. Unfortunately, from time to time poor Sax is set up as a bit of reductionist straw man. Take this exchange, from the beginning of the chapter 'Social Engineering', where Saxifrage Russell is talking to a hippy-dippy psychologist type:

There is a drive towards complexification that is directly opposed to the physical law of entropy. Why should that be?

I don’t know.

Why do you dislike it so when you can’t say why?

I don’t know.

This mystery of life is a holy thing. It is our freedom. We have shot out of physical reality, we exist in a kind of godlike freedom, and the mystery is integral to it.

No. We are still physical reality. Atoms in their rounds. Determined on most scales, random on some others.

Ah well. We disagree. But either way, the scientist’s job is to explore everything. No matter the difficulties! To stay open, to accept ambiguity…

I've written some new lines for Sax. I reckon it should go like this:

There is a drive towards complexification that is directly opposed to the physical law of entropy. Why should that be?

There isn’t a drive towards complexification. There’s a drive towards differentiation, a drive which is basically the same as the physical law of entropy. You have just selected your data to focus on the end of the bell curve where complex things are happening, ignoring the fact that the curve is getting bigger and broader all the time.

Well, you’re entitled to your opinion. But I think your view saps all the mystery out of the universe. This mystery of life is a holy thing. It is our freedom. We have shot out of physical reality, we exist in a kind of godlike freedom, and the mystery is integral to it.

Why are you so eager to call everything you don’t understand ‘a mystery’?

Its not that I’m eager, it’s just that I feel there’s more to life than can be explained by physical science.

Why don’t you stop feeling, and try thinking, instead? What if the mystery is just an artifact of your imperfect understanding? What if the mystery, and the ‘godlike freedom’ just exist in your head? And what exactly do you mean by ‘shot out of physical reality’? You should define your terms.

Ah, my friend, don’t be mean! We disagree. But either way, the scientist’s job is to explore everything…

Green Mars, pp.135, 177, 251-253

noreply@blogger.com (Chris Fellows) — Wed, 30 Sep 2009 02:47:00 +0000

One problem with schemes for the terraforming of Mars is the need for a source of an inert gas to give an atmosphere of similar composition to Earth. A higher partial pressure of oxygen than we have here would ‘vigorously accelerate combustion’, tend to intoxicate us, and make technological civilisation impossible, while a much lower total atmospheric pressure would not be able to support Earth-like weather. The partial pressure of oxygen required to support combustion declines with declining total pressure, so even this lower total atmospheric pressure option might be dangerously combustible if it had enough oxygen present to support life. So, where is this inert gas to come from?

Getting nitrogen from Titan won’t stand up to any sort of cost-benefit analysis.

There are unlikely to be enough noble gases trapped deep underground from radioactive decay to amount to a hill of beans.

Thus, it has been suggested that molecular nitrogen could be obtained by ‘burning nitrates’, which seem to be present (or may be present) in considerable amounts in the Martian crust.

However, simply heating nitrates will not be very effective as a way to ‘dilute’ oxygen. For instance:

2Na(NO₃)₂ + heat → 2NaNO₂ + O₂

2NaNO₂+ moreheat → Na₂O + NO + NO₂

2Ca(NO₃)₂ + heat → 2CaO + O₂+ 4NO₂

Thus ‘burning’ nitrates generates lots of toxic gas, and some extra oxygen.

Of course, with more energy input:

2NO₂ + much more heat → N₂ + 2O₂

So we have got some nitrogen eventually, but at a cost of 2.5 oxygen molecules per nitrogen molecule.

If we don’t want to add lots of extra oxygen to the atmosphere, we will have to add a reducing agent instead, and do something more like ‘burning’ . On Earth, if we had lots of extra nitrogen dioxide we wanted to get rid of, we would do something like:

NO₂ + 2H₂ → N₂ + 2H₂O

NO₂ + C → N₂ + CO₂

Or more realistically, something like

4NO₂ + C₃H₈ → 3CO₂ + 4H₂O + 2N₂

The problem is that there is not a lot of carbon or hydrogen on Mars that is not already incorporated in carbon dioxide or water. I haven’t googled to find out how much hydrogen has been located/postulated on Mars, but a crude atom balance suggests that if we want to burn nitrates with enough hydrogen to generate one nitrogen atmosphere, we need to burn at least two whole hydrogen atmospheres. I don’t think this is available, it would surely have outgassed long ago. I have found references to methane clathrates on Mars, which may be there in similar amounts to the nitrates (perhaps) and would allow the reaction

2NO₂ + CH₄ → CO₂ + 2H₂O + N₂

The problem here is that it would be a very significant bit of geo-engineering to mine the methane and get it to the nitrates, or vice versa, and we are adding to the carbon dioxide load that we need to get rid of later.

So what other reducing agents are available? I suggest that much more cost-effective than bringing nitrogen from Titan would be to bring down some Iron-Nickel asteroids and rust them in nitrogen dioxide. The mass that would be transported would be much larger, but the distance would be much shorter, and there would be no need to do any complicated collection and packaging and transport, just provide the right nudge of energy to send the asteroid on a collision course with Mars.

The following reaction is certainly thermodynamically favourable, though I don’t have an idea of what its activation energy might be:

6NO₂ + 8Fe → 3N₂ + 4Fe₂O₃

While this uses considerably more mass of reductant to produce the same amount of nitrogen than methane would, instead of having to be painstakingly mined and collected like the methane, the asteroids could be crashed down into the nitrate deposits in one foul swoop. The reaction does not produce any extra carbon dioxide that will need to be scrubbed out later.

Some Knols

noreply@blogger.com (Chris Fellows) — Thu, 10 Sep 2009 01:11:00 +0000

I thought I should put a link to Marco Parigi's knol on reading Richard Dawkins 'The God Delusion', and my knol on reading Stuart Kauffman's 'The Origins of Order: Self-Organisation and Selection in Evolution', as a prod to get myself to finish the latter!

Dark Matter?

noreply@blogger.com (Chris Fellows) — Tue, 03 Mar 2009 06:09:00 +0000

Every time I read back over my list of publications, I am struck by how most of the good ones seem to have sunk without a trace. Most of the ones where I thought I had discovered something interesting and novel about the universe, or had hit upon an interesting and novel way of looking at something we already knew about, have very few citations, or none at all. Perhaps I should do a series of posts on my top five papers with no non-author citations? Hmm, I have been neglecting this blog lately, and a theme like that might help.

Anyway, a few years ago a colleague gave me a weighty chapter he had written, entitled A Quantum Approach to Dark Matter, which I was slack (It is 63 pages long) and never got around to reading (It *is* 63 pages long). Remembering it today, I thought I would first check to see what other people thought of it- I am a mere chemist, and can only identify very dubious theoretical physics as dubious at a glance. I found my colleague had four published articles in the area over the past half-decade, and none of them had been cited at all. This is a tragedy. It is dreadful to spend years wrestling with an idea, to hone and shape it into a form you think is fit to present to the world, expound it with all the energy and clarity at your command, shepherd it into print, and then see it be ignored completely. Hence, I thought I would put a link to the chapter here. And I really will read it myself, I promise. And put an ignorant chemist's critique here on the web, at the very least, so Google can find it.

noreply@blogger.com (Chris Fellows) — Wed, 21 Jan 2009 05:34:00 +0000

Some time ago I was asking the question: ‘How good are these climate models? What sort of predictive value have they shown in modelling future climate? After all, we’ve been doing them for a few decades now.’

A nice person on realclimate.org (there are some, not all of them treat people who disagree with them as the demonised other) directed me to a classic paper by Hansen et al.

"If you want an indication of how well these models do you can go get (J. Geo Res. 93 (1988) 9341) the Hansen GCM paper that people talk about, and compare their results with observed patterns of warming and other things."

Here is the plot from that paper showing the response of overall global temperature (which the authors argue convincingly is a much better parameter than any subset of the data, e.g., whether it snowed at my house or not in a given year) for three different scenarios- A being continued exponential growth, B being a more subdued form of business as usual, and C if drastic cuts are implemented starting a few years ago.

I went and got the Hadcrut3 data set and plotted it on top of this one, as near as I was able, and got this.

There are other data sets out there. I shall plot some of the others and put them up for you.

The Hansen et al. model predicts the greatest degree of warming at high latitudes, fitting observations, but the model also reproduces another feature of observed weather, that those latitudes have the highest natural variability from one year to another.

In which I place myself beyond the pale of civilised discourse

noreply@blogger.com (Chris Fellows) — Tue, 04 Nov 2008 05:15:00 +0000

Firstly, an observation on scientific models, coagulated in the enthralling world of emulsion polymerisation:

Whenever you are trying to model some complex phenomenon, the fit of the model to the data can be improved by adding more adjustable parameters. A complex phenomenon will usually be dependent on a large number of factors, but the fact that the model fits the data better when you incorporate an additional factor may or may not mean that new factor is important: it might just mean that the additional parameter(s) you have incorporated are improving your fit. This is another thing the David Sangster told me: ‘With enough adjustable parameters, you can fit a camel.’

So there is a tension between the complete model, which contains all the factors that ought to be physically important – but might be meaningless because of all the guesstimated parameters you have put in to quantify these factors- and the simple model, which ignores things that might be physically important, but also avoids adjustable parameters. If you go too far in one direction, you get a model that can fit any possible data; too far the other, you get the well-known ‘assume a spherical horse’ punchline.

This also means that when you are modelling a complex phenomenon, you will tend to base your model on the processes that are best known, where you don’t have to pick numbers out of the air for your adjustable parameters, and you will ignore if you possibly can the role played by processes that are less understood, which would force you to bring in rubbery parameters.

Now to place myself beyond the pale. Some time ago I made the assertion:

‘Anthropogenic global warming is a fact, but we shouldn’t do anything about it.’

The second part of this statement is a considered opinion, based on facts and reasoned deductions from them. The first part of this statement, I have realised over the last few months, is based on an irrational mood.

That is: in the laboratory, and considering the atmospheres of the planets in toto, there is a perfectly splendid mechanism by which increasing the concentration of atmospheric carbon dioxide should increase temperatures. It is a really good mechanism, based on rock-solid physics. But is there any evidence that this mechanism is responsible for observed temperature change globally? Evidence, in the scientific sense, is where a model has predictive value: it does not just fit the data we have, but tells us what future data is going to look like. I did not examine this question before I made the statement above. Instead, I relied on the irrational mood that it seemed like wishful thinking that there was some sort of feedback mechanism providentially cancelling out this Greenhouse warming effect.

Let us consider these two famous graphs:

What do they tell us? They show us a correlation between carbon dioxide concentration and average global temperature. They also tells us, very clearly, that there are factors other than carbon dioxide which contribute to the world’s temperature.

We could also draw graphs that show some sort of a correlation between sunspot activity and global temperature, and earthshine and global temperature, and the number of pirates and global temperature. The last of these three graphs would be a joke circulated by the Church of the Flying Spaghetti Monster. The other two are graphs where it is easy to construct a testable mechanism for how the correlation might work. These mechanisms are not as solid or as well understood as the Greenhouse mechanism. They rely on more rubbery adjustable parameters. If we ignore them, do we have a spherical horse? If we include them, do we have a camel?

What is signal, and what is noise, in the Hadcrut3 temperature curve?

An idea that was in fashion when I was an undergraduate was the Gaia hypothesis of James Lovelock. You don’t hear much about it nowadays. You might remember that it was all about negative feedbacks keeping the global ecosystem in balance, life keeping things tickety-boo for life. I bring it up here as a hand-waving justification for a recent shift in my irrational mood: given that there is a grain of truth in Lovelock’s ideas, it now seems to me reasonably likely that there would be a negative feedback mechanism tending to minimise the effects of any carbon dioxide we add to the air.

I must now revise my assertion:

‘Anthropogenic global warming is a conjecture with limited predictive value, and we shouldn’t do anything about it.’

And I have to apologise for some of the slighting references to global warming denialists I have made previously.

And unfortunately I have nerfed one of the major motivations for establishing this blog, which was to use any perceived authority associated with my real name to push the line that we shouldn’t take any action to stop anthropogenic global warming. By denying AGW to be a fact, I have placed myself outside the pale of civilised discourse and disqualified myself from making any statements on the issue that will be taken seriously.

Son cosas de la vida…

14% more First Year students agree balancing redox equations is fun!

noreply@blogger.com (Chris Fellows) — Wed, 01 Oct 2008 03:33:00 +0000

In a striking improvement over last year's already high student enthusiasm for balancing redox equations, the proportion of students agreeing that balancing redox equations is fun has risen to 83%!

Googling Professor Ronald Laura? Part Five.

noreply@blogger.com (Chris Fellows) — Thu, 04 Sep 2008 10:11:00 +0000

“It is foolish, generally speaking, for a philosopher to set fire to another philosopher in Smithfield Market because they do not agree in their theory of the universe. That was done very frequently in the last decadence of the Middle Ages, and it failed altogether in its object. But there is one thing that is infinitely more absurd and unpractical than burning a man for his philosophy. This is the habit of saying that his philosophy does not matter, and this is done universally in the twentieth century, in the decadence of the great revolutionary period.”
- G. K. Chesterton

Here is part of an email I received last Friday which contains the gist of my correspondent's remarks:

I am requesting that you remove the abstract on nurturing gifted students from your blog, also remove any reference to Professor Laura (including his name) and I'd like that done as soon as possible please, today if feasible. I do not want to take further action but I will if the comments are still there next week. I feel I have to do this before any more damage is done to others that don't deserve it.

Here is another bit:

Considering you did not stay for the whole of Prof Laura's presentation, and that those who have posted on your blog have not even attended
any of or only one of his talks how can you justify comments like 'I have met the enemy!' That's disgusting! considering all the amazing
work that Professor Laura has done for others. How can you defame someone like that?

I think it is rather more disgusting that I could have googled Ronald Laura and not immediately found any criticism of his ideas or the way he presents them. If you have ideas that you believe are worthwhile, and you are at all interested in truth- as I am- then you hunger and thirst for criticism, for it is in responding to criticism that your ideas are tested and improved. If you are interested in convincing other people of the truth of your ideas- as I am- then you also welcome criticism of the way you present them, because this enables you to present them better. Even if you are not interested in truth, but only want to be transgressive in an adolescent way- as I hope I am not- then you have a positive need for reactionaries to jump up and down criticizing you. Otherwise, what would be the point?

I do not need to send my criticism explicitly to Ronald Laura, because I know he will find it. The beauty of the web is that all this criticism can take place in a completely public forum, and anyone can join in. Anyone who can find value in our competing visions of truth can derive value from it. Anything stupid I say is open to the world, as anything stupid he says is open to the world.

Users of the Web are perfectly capable of taking on board conflicting opinions and making up their own mind. If I told people to look up something Noam Chomsky wrote, they would find plenty of material on the Web written by other people who bitterly disagree with Noam Chomsky. If I told them something by Cardinal Pell could be useful to them, they would find plenty of harsh words directed against Cardinal Pell and his ideas. If I directed them to the work of Richard Dawkins, they would find no end of web-pages saying he was talking rubbish. If I asked them to google ‘string theory’ they would immediately find people claiming it is fraudulent drivel. If I asked them to google ‘global warming’ they would find pages claiming it is a vast left-wing conspiracy to abolish property rights, and pages claiming anyone opposing extreme measures to combat it must be a knuckle-dragging shill of Big Oil.

What is so uniquely fragile about Ron Laura that he should be shielded from all this? If he does not want to be part of this world, he should not post stupid things on the Web. My friend Klaus Rohde asserts on his blog that it is ‘common sense’ that John Howard should be put on trial for war crimes. This is vastly more insulting than anything I have written about Ron Laura, yet Klaus is yet to tell me of any good friends of Mr Howard writing him to demand he not 'defame' our former Prime Minister.

I do not intend to take down any of these posts. That said, should any readers with a legal background have the opinion that anything said could be likely to be construed as defamation, please let me know, as I have no wish to be sued by a rich and powerful Professor!

Update: I found a version of Ronald Laura's analogy about the Garden of Eden on the ABC website. It is not entirely clear whether he really thinks clothes are a bad idea, but that would explain his concern with developing washboard abs:

If there is a single defining characteristic of the modern age, then as I see it, it's probably the mindless commitment we have to technology as the panacea for virtually all our ills. In fact we have committed ourselves and been so bedazzled by technology if you like, that we have essentially theologised technology. We've turned it into a way of, I suppose, taking on the pretence of playing God ourselves. In the Garden of Eden story the serpent tempts Eve to eat of the Tree of Knowledge. She then in turn tempts Adam to eat of the Tree of Knowledge. When he does, they suddenly become shamed and conscious of what seems surprising in itself, their nakedness.

Now within that context, occurs the first act of technology if you like, namely the sewing of the figleaf. They sew the figleaf and turn to technology to do that, as a way of covering their external nakedness. I want to suggest that the problem at the outset was never their external nakedness, it was their internal nakedness. Their shame in respect of alienation from God, their disobedience, their failure to live by way of honouring the beauty of the garden, the gift of the garden, the gift of their life in relation to God.

So in essence what I'm saying is that by virtue of sewing the figleaf, and covering their external nakedness, what they actually really do is turn away from the deeper problem, and what it does is to apply or appeal to technology as a way of avoiding having to confront the wages of their actual sin. The sin of disobedience, the sin of alienation, the sin of not living as God would have them live in the garden.

So for me the story is very powerful as I've recast it as a way of saying that first of all the Garden of Eden story, in this sense, needn't be construed as a past and defined event which occurred long ago in time. I see it as a dynamic event, unfolding constantly in history in the way it reproduces itself through our interactions with nature and each other. We're constantly as a race, a group, humankind, presented in beautiful garden scenarios which unfortunately we continuously despoil.

In fairness I also read the hardcopy text of this article, from 1986, which is actually quite reasonable. His theology of transcendence is not particularly new- I'm sure I've read C. S. Lewis saying essentially the same thing, and before him, St. Augustine (So possibly it goes back to Plato- what did they teach me in those schools?)- but it appears that once upon a time Prof Laura was doing intellectual work of some value, before he went off the rails into a technology-is-evil obsession.

A little note about chain transfer to butyl methacrylate

noreply@blogger.com (Chris Fellows) — Fri, 01 Aug 2008 04:28:00 +0000

For good or evil, this paper, which I began writing in 1999 at the request of Professor Bob Gilbert, is finally published. It is a tremendous pleasure to finally be a co-author with David Sangster, the eminence d'or of Australian polymer science. He is the source of the quote which informs my every waking action:

'Just because the model fits the data, it doesn't mean the model is true.'

I have today (10/11/09) found a splendid biography of David Sangster on the website of the University of Sydney.

Royal Society Discussion Paper, Ocean acidification due to increasing atmospheric carbon dioxide. Part Two.

noreply@blogger.com (Chris Fellows) — Tue, 29 Jul 2008 06:05:00 +0000

The RSC discussion paper explains the division of ocean waters between an upper zone, where calcium carbonate formation is possible, and a colder lower zone, where it is not possible. The fact that mass transport between these zones is very slow is stressed. The paper does not actually give a pH profile of the ocean, but here is one:

(The little dark dots are the data from today; the big circles are attempts to figure out the situation at various times in the past, which is what the paper I sourced this from is about.)

Note that the vast majority of the volume of the ocean is cold, and relatively acidic. This deep ocean is where an enormous amount of carbon is stored. Transport of carbon dioxide out of or into this layer will not be controlled by thermodynamics (i. e., where carbon dioxide it would most dearly love to be), but by kinetics (i. e., how fast it can get there). Thus, it does not matter to this zone whether or not we are adding carbon dioxide to the atmosphere at a rate unparalleled in Earth’s history or not, because that will not control how fast it gets there. It has to run the gauntlet of the warm water- where it may or may not be converted into calcium carbonate- first.

Remember the figures in the last post on how the carbonic acid equilibria change with temperature. I am now going to make the assertion- which I should now go out and try to verify- that the deep ocean is more acidic *because* it is cold.

To qualify this as-yet-unverified assertion of mine, I should say that I have not yet found any data on the pressure dependence of the pKa values in solutions of reasonable ionic strength, which is also likely to be important.

I suggest that the temperature gradient of the ocean is probably what generates the pH profile, and because transport of carbon dioxide into or out of the ocean is slow compared to how much is already there, it is the temperature dependence of the carbonic acid equilibria which control the speciation observed. Note also that the boundary between the carbonate-forming zone and the non-carbonate forming zone, from our figures below showing what the equilibria do, is going to be dependent both on the pH of the upper layers and their temperature.

Now… if climate change means anything, it means the oceans warming up. Heating the ocean and reducing the pH will pull the carbonate/bicarbonate equilibrium in different directions. I don’t know which is likely to be more significant.

Because the historical record does not show carbon dioxide spouting out of the ocean immediately as temperature increases, but lagging about 1000 years, I am not at all worried about degassing of carbon dioxide starting some feedback loop of badness : until that cold lower ocean where most all of the carbonic acid species are sitting warms up, there is no reason for significant amounts of carbon dioxide to leave the ocean. That is, if degassing of the ocean *is* the reason for the increase in carbon dioxide lagging historical temperature changes. It might not be.

Royal Society Discussion Paper, Ocean acidification due to increasing atmospheric carbon dioxide. Part One.

noreply@blogger.com (Chris Fellows) — Fri, 18 Jul 2008 03:39:00 +0000

My thoughts keep returning to the ‘de-alkalinisation of the oceans’. I started thinking about this the other day, first because I came across that article on coccolithophores in Science, and second because one of my students is writing a review article on the use of polymer additives to stop scale formation in desalination plants. The main scales formed in these plants are calcium sulfate at high temperatures, but at somewhat lower temperatures calcium carbonate or magnesium hydroxide.

The first thing you want to know about, if you want to stop scale forming, is what are the characteristics of the solution it is forming from. So early on in the draft appears this table:

(TDS is ‘total dissolved solids’.)

I went back and had another look at the Royal Society discussion paper that I referenced before. This is the paper referenced everywhere in the web where people are fretting about ocean de-alkalinisation. The range of pH values quoted in this table is greater than the range shown in the pretty map in the Royal Society report. In fact, the range of pH values in this table is greater than the size of the maximum change in surface water pH they predict for Figure 5.

So my first thought was, if changes in surface seawater alkalinity are likely to cause bad effects, we ought to be able to see these effects already in ‘canary in the coalmine’ water bodies- shallow, warm places like the Persian Gulf. The reefs there don’t seem to be in particularly good shape but there doesn’t seem to be any evidence that seawater alkalinisation is contributing to their woes. Anyway, this table got me thinking about the problem again.

In discussing the formation of calcium carbonate scale, my student had to talk about the dependence of the equilibrium constants K₁ and K₂ on temperature and the total ionic strength of the solution, and had referenced this paper by Millero et al., where the following figure appears:

The Millero et al. paper also summarises data from a lot of previous work and gets it all to fall on the same line- see this, for instance:

In case you don’t remember,

pK_a = –log₁₀(K_a),

and in this case, K₁ is the equilibrium constant for the reaction:

H₂CO₃ → HCO₃^– + H⁺

and K₂ is the equilibrium constant for this reaction:

HCO₃^– → CO₃^2– + H⁺

These figures are telling us that in seawater (where I^0.5 ~ 0.83), the equilibrium position of both these reactions is further over to the right hand side than if they were happening in common or garden distilled water. And they also tell us that the warmer the water, the further the equilibrium will be over to the right hand side as well.

I plotted up a graph showing how the speciation of pH should change in seawater using the values in this paper and got this figure:

The Royal Society Figure 2 is pretty much the same as mine. It shows carbonate kicking in at a slightly lower pH, but there are different K₂values floating around in the literature and I'm not sure what value they used.

Zooming in on the pH range important for discussing what is going on in the oceans:

Getting rid of the log scale, and looking at the carbonate/bicarbonate equilibrium only:

More to follow.

C'est la vie

noreply@blogger.com (Chris Fellows) — Wed, 16 Jul 2008 04:41:00 +0000

A while ago the prolific Anonymous asked me:

What do you think about the de-alkalinisation of the oceans. Anything ruinously doom and gloom possible there? Is adaptation of water species quick enough by your reckoning?

I have recently been thinking about this a lot, due to work I am doing on calcium carbonate formation in desalination plants, and will offer a substantial critique of this particular bugbear soon.

But in the meantime, I came across this nifty figure in Science the other day and thought I would share it with you. If someone had asked me, 'how will marine organisms respond to changes in total carbonic acid species concentration?', I like to think I would have been prescient enough to draw a figure like this one. Find a niche and fill it: such is the way of living things!

Dialogo

noreply@blogger.com (Chris Fellows) — Wed, 09 Jul 2008 06:01:00 +0000

Simplicio: Have you heard? The Powers wish to reduce the amount we teach, so that we will have more time for research, and thus will produce more and better research.

Sagredo: I think the second part of your syllogism does not follow from the first.

Simplicio: Why, how is that?

Sagredo: One of us cannot have more than twenty-four hours in a day. But if one has a single intelligent and dedicated postgraduate student, then one has forty-eight. If one has two, one has seventy-two, and so forth. It is the many hours that come from having many students that enable us to produce more and better research.

Simplicio: True, but I cannot see how having a few more hours for research can hurt us.

Sagredo: Where do you suppose postgraduate students come from?

Simplicio: Most of them are from places like Tartary and Hind, are they not?

Sagredo: Yes, many of them are. They are attracted from diverse foreign lands by the splendour of the learning in our land. But many other places of learning seek also to attract them, and day by day the scholars of their own lands grow wealthier and more astute, so that one day no more will come to us.

Simplicio: That would be a calamity! So where else do they come from?

Sagredo: We raise them here, by teaching undergraduates.

Simplicio: Aha! There is no problem, then. Under the new system we will surely continue to teach undergraduates.

Sagredo: Simplicio, do you suppose all undergraduates are suitable to become postgraduates?

Simplicio: I guess not. Some are damnably simple.

Sagredo: Yes, it is only the few who hunger and thirst for knowledge that are suitable to become postgraduates. If we give our undergraduates half as much as we did before, and other places of learning continue to offer a full cup of learning, where will undergraduates like that go?

Simplicio: You think they will not come here?

Sagredo: Many of them will not.

Simplicio: But surely there are many who would not leave our lovely place of learning for the City of Dreadful Night or other distant places?

Sagredo: Yes, we must pin our hopes on such as those. But consider: if we teach them half as much, what will we need to do when they commence as postgraduate students?

Simplicio: I am not sure. I recall there are forms to fill out?

Sagredo: Besides that. We must perforce teach them the other half, if they are to work as well as postgraduates in the City of Dreadful Night work. And when we have done that, what must we do?

Simplicio: I suppose we must fill in some more forms.

Sagredo: Yes, for by then the first year of their candidature will be over.

Simplicio: It would seem, then, that you think this change will diminish our chances of doing more and better research, rather than increase them?

Sagredo: Most certainly. Why would a student who would make a good postgraduate in Physics or Chemistry do an undergraduate degree at a place of learning that does not take that discipline seriously?

Simplicio: Then I suppose the Powers wish to reduce our teaching hours for some other reason?

Sagredo; That is what I had thought.

Simplicio: Perhaps it is that they must be reduced because of this thing that has come from Bologna?

Sagredo; Ah, but the places of learning that have already gone down that path teach many more hours than we do.

Simplicio: Hmm. Perhaps it is, Sagredo, that those studies they wish to cut are only those where the numbers of undergraduates have been falling, so that we may conserve our resources, as our wealth wanes?

Sagredo: That would be a sensible course of action- but you see, Simplicio, it is the studies where numbers of undergraduates are holding steady that the Powers wish to cut back.

Simplicio: Ah.I see. Perhaps- no, that makes no sense. (sighs)
I wish Salviati was here to explain what was going on.

Sagredo: So do I, Simplicio.

Simplicio: It is a pity the Powers never replaced him, when he took his renowned research group to Brescia...

Googling Professor Ronald Laura? Part Four

noreply@blogger.com (Chris Fellows) — Thu, 26 Jun 2008 23:06:00 +0000

Another extended comment has arrived on my first post on Professor Laura:

Quoth Anonymous:

Do the words "baffle with bulls#*t" ring much truer when talking about Ron Laura.

I have a Masters degree in Exercise Science and have worked all over the globe in professional sport and also competed at a very high level in a strength and power sport and feel that regarding Professor Laura's words on Health and Fitness are just that, words. Professor Laura is somewhat of a running joke in academic circles regarding his philosophies on health and fitness.

Many peer reviewed experts in this field shake their heads in disbelief when hearing of the advice professor Laura gives. I will give him one bit of credit, that is, he is a marketing genius.

No one i have come into contact with in the powerlifting, bodybuilding or the strength community has even heard of Professor Laura, areas in which he claims to have excelled in. Also if Professor Laura is such an expert in this field then why hasn't he published proven research to his claims in peer reviewed journals or spoken at conference's whereby experts in their respective fields gather to exchange ideas and debate current issues? No not Professor Laura he only preaches to the general population whereby he can get away with extravagant words and stories.

Last of all I graduated from the education faculty at the University of Newcastle and can assure you that in the four years I attended Professor Laura did not lecture in the PDHPE or secondary education department the only area I know of that he was involved in was the final year teacher research project whereby he was quite popular amongst the students as he was known to never fail anyone and always give high grades.

People like Professor Laura really upset me because I worked very hard in sport and study to get where I am today and it saddens me that there are some people out there that use technical jargon and marketing brilliance to fool the general population into forfeiting lots of money on schemes and gimmicks.

So Chris don't worry there are many, many people some in very prestigious positions in education and health that feel exactly the same as you.

Two Cultures are Better than One

noreply@blogger.com (Chris Fellows) — Tue, 24 Jun 2008 23:35:00 +0000

I have been asked to read this document in preparation for a meeting of the School Research Committee. It would be cruel to ask you to do so as well, but if you want to, please go ahead. It is basically a proposal for muddling the 'Two Cultures' back together in a porridge by structuring humanities studies around 'evolutionary theory' and stressing that 'evolutionary theory' is a 'form of narrative that functions within its social and historical context'.

I assert that:

Inappropriately mixing poorly-thought-out ideas from biology with the humanities gave us the First World War, the Second World War, and the Holocaust.

Inappropriately mixing poorly-thought-out ideas from the humanities with biology gave us the only comparable man-made catastrophe of the second half of the 20th century, the famine associated with Mao's 'Great Leap Forward'.

Let's not go there.

Googling Professor Ronald Laura? Part Three

noreply@blogger.com (Chris Fellows) — Tue, 24 Jun 2008 06:19:00 +0000

I just thought I would take a comment that appeared recently on my first post on Professor Laura and put it up here in a post of its own, with my response.

Quoth Anonymous:

Hi Chris,

I have seen Ron Laura speak too (in January this year) and I completely understand your perspective given your experience.

However, I stayed through until the end and was left with a different response. I thought it was the most inspiring piece of speech making I have ever heard.

I was not alone.

Another woman like me sat silently afterwards in awe of his level of insight. Her comment; 'it is rare to have the good fortune of being in the presence of someone with such a deep level of understanding'.

I can understood your feelings about the lack of dialogue (and no doubt he would too). However, I felt he connected with us in a different and much deeper way with his speech.

And when I spoke to him afterwards I found him very open to dialogue and totally lacking in arrogance. I don't think he could have transferred his insights with the same degree of effectiveness with dialogue.

What I found most impressive about Ron was that he supported spritual insight with intellectual rigour. It is all too common for spiritual insights to be destroyed by intellectual rigour ...or for them to be conveyed without intellectual rigour.

As for the suit...I understand that you may have related that to the rich and expoitative. I interpreted it as a sign of respect for us as his audience (and for himself).I felt honoured by it and prefer it to the "i don't think you are worth getting out of my jeans' attitude'.Not dressing formally can be a sign of arrogance too. I'll meet you half way on that point...perhaps smart neat casual would have sufficed.I would prefer to see him look more comfortable himself.

All in all Chris I understand your viewpoint given your limited experience of Ron and your frustrated desire to receive support for your child. I really do.

However, I think your blog could do a good man alot of harm. And by the sound of it you don't seem to be the kind of person who would be consciously malicious. Those of us who are creative or gifted ...or who have gifted or creative children or children who need their creative expression supported ...truly need people like Ron in positions of power and influence. With further listening I think you might find that he is actually batting for the same team as you.

I would recommend giving Ron and his work a second chance (or at least let him be).

Good luck with getting the support that you need for your child.

Mary

To which I replied:

Thanks for your message, Mary! I’m glad you put in the effort to write to me. I don’t know if you will ever come back here to read this, but here goes.

Did you read my other post where I unpack a bit more just what I thought was wrong with what Ron Laura said and how he said it?

Given that the content of the talks we attended may well have been different, I also felt how inspiring he was. This is what scared me. A lacklustre speaker with dangerous ideas is nothing to be afraid of. Someone who can get people nodding happily in response to ideas that have been proven to be extremely harmful (e.g., the ‘culturally appropriate’ Aboriginal education I referred to) is a real danger.

I’m not saying that he should stop saying what he believes, still less that anyone should try and stop him from saying it. I did a search and couldn’t find any mention of his name in the context of ‘the Emperor has no clothes’. If I had, I probably wouldn’t have written anything. But I didn’t find anything, so I felt it was up to me to provide a smidge of balance.

I don’t think my little blog can do him any harm whatsoever. When our ideas are challenged, we are either driven to improve how we explain them, or we abandon them in favour of better ones.
Again, the talks may have been very different, but I did not detect a great deal of intellectual rigour in the talk I attended. He only tore down what other people had built, he did not give any coherent picture of what he would replace it with. I couldn’t find a logical exposition of his worldview on his website, either, nor in his book ‘The Perils of Progress’. This is another thing that worried me.

If someone want to throw away the one means of knowledge at our disposal, I want to know what they intend to use instead. If they say: ‘I believe in the infallible Qur’an’, fine. If they say: ‘Here, I am following Marx,’ fine. If they say: ‘My philosophy is based on these seven core axioms revealed to me by the Squid God,’ sure, why not. But leaving your own position cloaked in fog puts the other person at an unfair disadvantage.

Things I don’t understand: The ‘Collapse’ of the Wavefunction

noreply@blogger.com (Chris Fellows) — Mon, 23 Jun 2008 03:14:00 +0000

(NB: Let it not be supposed that the long delay since I last wrote something headed ‘Things I don’t understand’ means that there are not many, many, many, many other things that I don’t understand.)

In chemistry, the results of quantum mechanics that we are interested in are spectra. Whether these are lines in the ultraviolet/visible region corresponding to transitions between electronic states, or lines in the infrared region corresponding to transitions between vibrational states, or lines in the microwave region corresponding to transitions between rotational states, they are all transitions between energy states which are quite nicely defined.

We cannot ‘observe’ a chemical system in a particular state. We do not make a ‘measurement’ to see what state it is in. What we observe, what we measure, is its transition from one state to another. It seems entirely useless, as well as nonsensical, to say that a particular molecule was not in its first excited vibrational state until we hit it with a photon to give an anti-Stokes Raman peak.

In fact I am really quite vague about what sort of experiment you would do, in the traditional orthodox quantum mechanical sense, to measure the state of a system in such a way that its wavefunction ‘collapses’.

I don’t like the ugly discontinuity that the ‘collapse’ of a wavefunction introduces to quantum theory.

I don’t like the appearance of a privileged status for an ‘observer’ it introduces.

I especially don’t like the whole elaborate mass of New Age piffle that has been erected on this privileged status, a mass which has infected and compromised the otherwise splendid ouevre of Greg Egan, for instance.

A while ago I first came across de Broglie’s pilot-wave theory, and was impressed in my naive chemist’s way by the straightforward way it cut through the paradoxicality of the two-slit experiment. I wanted to know how this model had been developed since de Broglie cast it aside, and how the ‘collapse of the wavefunction’ looked in the pilot wave model. I couldn’t find anything then, because I didn’t know enough to look for the ‘de Broglie-Bohm’ model.

Apparently the collapse of the wavefunction is not a problem in the de Broglie-Bohm model. So it is non-local. Big deal. Every 1s hydrogen orbital wavefunction we tell our first year students about has a non-zero value at every point in the universe (though Excel, bless its heart, says with 15 digit precision that it is zero more than about a nanometre away from the nucleus). Better non-locality than mystical Copenhagen interpretation waffle about an ‘observer’, or worse yet, the deeply dippy ‘Many Worlds’ interpretation.

But why the de Broglie-Bohm model doesn’t get into trouble with the wavefunction collapsing- that’s something I don’t yet understand.

Down to four out of six

noreply@blogger.com (Chris Fellows) — Thu, 19 Jun 2008 04:14:00 +0000

This letter, to The Australian's Higher Education Supplement, didn't get published either. So here it is:

I was saddened to read Barry Brook's endorsement of the cry 'Don't feed the troll!' If you are in the business of science education, you should treat every comment on your blog as a legitimate inquiry from a seeker-after-truth and respond politely. If your science is good, it will be obvious to your other readers if their response is to "sidestep valid critiques and ignore counter-evidence". If your science is good, it also doesn't matter how many times you repeat yourself. You will be improving the delivery of your message all the time.

It doesn't do any good to call people who disagree with you names ("sceptics, denialists, contrarians, delayers or delusionists" ... "cut of the same anti-intellectual cloth") or accuse them of being on the take ("Groups with vested interests in business as usual..."). If you are trying to communicate with those who are not already in your camp, such ad hominem attacks are worse than useless.

I thought it was unfortunate that an article entitled 'Science must prevail' contained no actual science. A calm 622 words outlining the physical mechanism of the Greenhouse Effect and the observational evidence for anthropogenic global warming would have been a much better use of space.

Best regards,

Chris Fellows