Thursday, August 13, 2020

Money and Economics

Money and Economics

Modern human culture arrived and swept all before it from 100,000 to 30,000 years ago.  It has a lot of features, including symbolic communication (also known as "language"). Developing at that time, was the symbolic representation of wealth: the right to access resources. This was an essential part of the major evolution of modern humans that allows us to live in large groups, instead of in the small groups where everyone knew everyone else.

Money

Cowrie shells of a narrow range of sizes were one of the early forms of money. This is because it took a significant and fairly constant amount of effort to find them. This is the "proof of work" theory of money, which led to the invention of cryptocurrencies such as bitcoin. Gold and silver mining came to dominate money creation, even though the amount of work involved is more variable, leading to inflation events such as when Spain received a lot of South American gold, or when the Emperor of Mali took the Hajj pilgrimage in 1324 (seriously).

From the beginning, money has tried to do two jobs that are not perfectly compatible: one is to act as a medium of exchange, and the other is to act as a store of value. We are psychologically confused about this, with a strong expectation that it should act as a store of value. A common error is to assume that when money fails to act as a store of value then that is because of government printed paper money, and that would not be a problem with a "proof of work" money system such as gold. The assumption is that the money should retain a value equal to the work that went into it, but that is false because the work happened in the past and can't be undone, and the value is set by current events, as I'll describe later.

Bitcoin is a perfect example of money as a medium of exchange. Its use is primarily this: the buyer first exchanges some of his local currency for bitcoin; then they use that bitcoin to buy on the internet; then the seller takes the received bitcoin and exchanges it for her local currency. This is certain to correctly reflect the exchange rate between the buyer's and seller's currencies, because if it didn't there would be money to be easily made by looping some money through the FX (foreign exchange) and bitcoin routes. For this use of bitcoin as a medium of exchange, it doesn't matter what the current value of bitcoin is, as long as it doesn't go up or down too fast. And indeed we've seen big swings in the price of bitcoin, but usage has continued. 

Another example of a medium of exchange that is never held for long is a paper currency that is experiencing significant inflation. In this case, as with bitcoin, the value of the currency is dictated by the amount of use it is getting. For bitcoin, where there is limited production, the value can go either way, but since it depends on decisions by many people, it is inherently unpredictable. However some people keep a significant bitcoin holding, as if it was a store of value, and the existence of these stores means there is always a risk that the market will be flooded by people trying to cash them in.

Value

When the economy is functioning correctly, it continuously produces things of value at the highest possible rate, giving something close to full employment. The things of value that it produces are services. A car or a train provides transportation services. A house provides shelter and accommodation services. Owning a house provides a security of shelter service.

To produce services you need assets: houses, cars, people with skills and time, and much more. What services an economy can produce depends on what assets it has. What services an economy does produce depends on who has the economic power to decide. In a pure market economy that power is precisely money. In our society governments and banks have substantial additional power.

If value consists of services continuously produced, then what is a "store of value"? Non monetary stores of value are just assets that can be put to use producing services in the future (whether or not they are currently used): houses, machinery, stores of non-perishable raw materials, and much more. The relative value of these things changes, so the concept of a store of value is a fuzzy one. Can money be a store of value?

Gold acts as a form of money. It has industrial uses, but the amount of gold stored vastly exceeds any such requirements. Also the price of gold is artificially high because of all the storage. We have to deduce that gold only acts as a store of value because people expect that it will, and that expectation is no different from the previous expectation that cowrie shells would retain their value.

Suppose that, for some form of money, the value of the money (what it will buy) is steady or going up (deflation). Then people are inclined to save it for the proverbial rainy day. If the currency has limited production, such as gold or bitcoin, then the fact that money is being taken out of circulation means there is less money chasing the same amount of goods, so prices must fall. Which is the same as saying that the value of the currency is going up. This further increases the inclination of people to save because if you can defer a purchase you pay less. But the "rainy days" that people are saving for are not always uncorrelated. When a pandemic or a weather disaster comes along, then that money comes out chasing a supply of goods that can't quickly increase, causing instant inflation. We see that saving money is not the correct way for society as a whole to prepare for an emergency, and that money with limited supply can mislead people into thinking it is a store of value.

A real store of value must be linked to future production of services, because that is the real economy when you strip away the veneer of money. Later we'll consider how to do that.

Currencies

Currencies should be optimized for the role of being a medium of exchange. And indeed that is what modern Reserve Banks try to do, and largely succeed.

Though the currency is a medium of exchange, still the participants in the economy want to keep a buffer of money. They don't want to have to liquidate an asset whenever they need to buy something. But as we've seen, it is unhelpful if there is any incentive for people to hold large quantities of the currency, because then the authorities lose control of this vital part of the economy. The Reserve Banks have found that 2 to 3 percent inflation is ideal. People can hold plenty of currency for exchange purposes without significant loss, but everyone has a big incentive to buy or invest to avoid their wealth melting away over the longer term. So the money keeps going around at a moderately constant rate.

If there is excessive inflation then the Reserve Bank can soak up money by borrowing money (selling bonds) which raises the interest rate. This actually presents itself as raising the interest rate. Presumably it is easier to work out how to counteract a particular amount of inflation by specifying a particular interest rate and borrowing enough to hit that target.

If inflation is too low, or there is deflation then the Reserve Bank can counter that by lowering the interest rate by buying bonds to put more money into circulation. There are minor and major problems with this. A minor problem is that there may not be enough bonds to buy back, which has been solved by buying other organizations' bonds. The major problem is that if money isn't circulating, which is what happens in recessions, then adding more doesn't help much and makes the situation less stable. I should admit that I don't understand the detail of how Reserve Banks function, but I think this is close enough.

Using interest rates to control the economy is fundamentally wrong since it has random effects on many people who need to live off a risk free investment. Currently interest rates are close to zero, forcing Reserve Banks to move to what they call quantitative easing. Buying non-bank bonds gives wealthy debtors free money, aggravating the rising inequality in our society.

For a stable economic system we want the interest on safe investment to be fairly steady. Historically it looks like inflation plus 3 percent might be the right number. This allows people to save for retirement expecting that they can expand their capital at the rate of inflation and also have income to live off. To achieve this we need an alternative to low interest rates to inject money into the economy.

I propose that there be a "tax on low inflation". When there is deflation or low inflation, the Reserve Bank will create money and pay it to the tax office. The legislation for this tax will require that it be spent almost immediately, and that any that cannot be so spent should be sent immediately to the general population, as the Australian Labor government did in the GFC. 

Another way the government can spend the low inflation tax is to buy something from another country, as long as the money can be spent immediately. How does that work? The government buying foreign currency lowers the country's exchange rate. That makes it easier for local industry to sell for export. It also causes immediate inflation by raising the price of imported goods.

While the tax on low inflation will be a big improvement in normal times, it does leave the situation where a lot of money is in private hands and can, in certain circumstances, flood the economy.

A Value Store Currency

We increasingly deal with money through computer software. That makes it easy for us to deal with multiple currencies. We have seen the difficulty of a single currency being both a medium of exchange and a store of value. It is natural to ask if we can separate out a 2nd currency that is a store of value. I have a proposal.

Value is services, provided by assets. A store of value consists of assets that will contribute to providing services at some future time. But such assets have variable lifespans, and they vary in their relative value over time. What we want for our value-storing currency is for it to represent a right to part of a collection of assets, that is maintained in a way that preserves its value. Explicitly:

We'll call our value-store currency "doubloons". People can interchange doubloons and dollars at any time at the current rate. The intention is that the exchange rate changes will be identical to inflation (for some reasonable definition thereof), so that the purchasing power of doubloons will be constant.

The government keeps non perishable assets whose value matches that of the outstanding doubloons. When people cash in their doubloons, so that there are then less outstanding, then the government sells some assets to keep the store level correct. When people buy more doubloons, then the government uses the dollars it gets to expand the store.

When the value of the assets held rises faster than inflation, then the government can sell some and pocket the money. However if the value doesn't rise fast enough then the government commits to expanding the store using tax money.

The government has an obligation to keep stores of things to prepare for an emergency. PPE (personal protective equipment) and oil have been in the news lately. It is intended that this value-store be used for this purpose, though the government has to make up any costs from storing perishable items that need to be constantly refreshed (such as food). When an emergency does strike then the government should replace the assets it then needs with others.

The store should not be an arbitrary collection of assets, but rather cover a wide range in the right proportion, so that the country can continue to operate during periods when it is cut off from suppliers for any reason.

Since there are costs associated with supporting this, it is envisaged that it will be for citizens and local organizations only. All they are allowed to do is convert the currency to or fro. It still makes sense to have loans and other financial operations denominated in doubloons, but when the time comes to do the actual financial transfer it is actually done in dollars calculated at the current rate.

Foreign Currency Exchange

We see the breathless news item "there is a current account deficit/surplus". What does that mean? When there was fixed exchange rates then a current account deficit meant that more people wanted to sell the local currency than there were people who wanted to buy it. So the government was forced to sell its foreign currency or gold holding to preserve the fixed rate, and this couldn't continue indefinitely. It was an urgent situation. Eventually the government would be forced to reduce the price of the local currency, changing to a new fixed exchange rate. Investors who guessed this would happen made a fortune.

Now that we have floating exchange rates, running a current account deficit is neither positive nor negative. It has a different meaning. A current account deficit means that more goods and services are coming into the country than are going out. And yet the currency has an equal number of buyers and sellers. How can that be?

The answer is that the extra buyers of the local currency are buying things in the country which they then don't take out of the country. This might be real estate, or equity in a business or it might be a loan. So one way to look at it is that a current account deficit represents foreigners investing in the country. Another way is to say that there is net borrowing from overseas. There is no way to distinguish between these.

On the other side, a current account surplus sounds like a great thing, but it might just mean that foreigners are disinvesting in the country.

When countries share a currency, such as the European Euro, then that is taking fixed exchange rates to extremes, since countries don't have the option to modify their rate. This was a big problem in the Eurozone, with poorer countries teetering on bankruptcy. This is potentially a problem in federal countries like the USA and Australia, which have states with substantial economic independence. In those countries the solution is for the central government to arrange wealth transfer from richer to poorer states. It seems that the Eurozone has now recognised the need to do this, with the European Central Bank buying government bonds of the poorer states at low interest rates.

Reality versus Finance

When I was a kid in the mid-1950s, the milkman delivered milk to our door. With cream on top, but I digress. He just had to run between the vehicle and the doorsteps because the vehicle advanced by itself using natural intelligence. Yes it was horse drawn. Sixty five years later and artificial intelligence hasn't caught up. But by the 50s horses were already rare.

What caused the Great Depression of the 1930s? In our assets plus services economic model, what happens if you suddenly lose a lot of assets? Obviously the total ability of society to produce services is reduced. It is the job of government and the finance sector to figure out what to do about that to produce services at the rate needed for full employment.

The 1920s and 30s was a period of transition. People were moving from the country to the city. In the country they had tremendous skills for dealing with horses and other animals. Even in the city horse skills were very valuable. The move to mechanization threw those skills in the bin. At a moment in time when there was a tremendous need for new skills, the market was flooded with labour that was unskilled in the new context.

Governments could have handled this better. Yes it would have been good to get the unemployed people to work building infrastructure such as roads. Pouring money into the economy and blowing some huge asset bubbles would have helped, and that's what we would do today. But really the right answer was to identify the training needs and make that happen.

That would have been hard then, but maybe we can leverage the Internet to do it now. Which brings us to the next section.

Pandemic Economics

In the pandemic there are many services, recreational and optional, that are much less used. But there is also less employment so it balances out. Except that the unemployment is not evenly distributed. So the government is paying the unemployed in various ways. This maintains the consumption of essential services like food, so that essential services are not also reduced by lack of demand, as happened tragically in the Great Depression of the 1930s.

If we think about services, the first question is what extra services could be provided while restrictions are in place. Most of the people who are underemployed have skills that are not currently useful. So extra work would have to be relatively unskilled, and shovel-ready. This is hard, though it does seem that in Australia some unemployed people could be employed doing fuel reduction to reduce the impact of bushfires.

We can also try to prepare by considering what services will be wanted when the pandemic is under control. A lot of people will want a holiday, including people who usually go overseas but will now stay closer to home. A lot of people will be keen to save, having blown their savings, or because they are behind on their mortgage. This will create unemployment unless the government steps in with community wide services. There is plenty that needs to be done.

Most of all we need to give unemployed people the ability and incentive to learn new skills.


Tuesday, August 11, 2020

The Virus Problem

 The Virus Problem

I'm not a doctor or a biology expert. This is just based on my concept of common sense. For the purposes of this article, I will use "bacteria" to mean living things that don't try to get into cells, though there are others; and I will use "virus" for things that need to get into cells, though this also includes intracellular parasites such as malaria and toxoplama.

For bacteria the immune system has a problem because there are good and bad bacteria, and the body has to distinguish. However the good are only in special places like the skin and gut, and mostly when they are in the wrong place the answer is to attack and kill and that works well most of the time for most people.

Viruses get into cells, and that is much harder for the body to deal with. The body has a complicated system for dealing with viruses before they get into cells and that is great except that a lot can happen while it's getting its act together.

The problem is: what to do about infected cells. In the early stages the answer is to kill the cells and hope to make up for the damage later. But when too many cells are infected then that can be a bad plan, because losing too many of an important type of cell can kill you. Plan B is for the cell to shut the virus down as much as possible, and for the immune system to tone down the cell destruction to a manageable level. Viruses that are well adapted to humans seem to know to tone down their attack to not kill their host, since that is a bad career move for them.

Humans form a vast monoculture across the planet. Monocultures are extremely prone to disease. We are lucky to have the SARS-CoV2 virus as a wake-up call. We need to wake up and decide to attack all viruses, planet-wide. This means:
  • Testing, particularly of people travelling. We are mostly looking for anything new, or known to be virulent. E.g. temperature checks are an easy test, and everyone with a temperature can be followed up. Sereological testing for antibodies is good, if it can be done easily, perhaps with a finger prick.
  • Reporting. Let's get a continuous global view of the health of our monoculture.
  • That will let us isolate and attack areas of infection.
  • Aim high. We want the total elimination of viruses and other intracellular parasites.

Saturday, August 8, 2020

An Internet Education Infrastructure

 An Internet Education Infrastructure

Australia has proved a popular destination for tertiary students to get University degrees. This has been good for the economy, but is not going to come back soon, and it may never come back. And yet what are people going to do during the coming period of high unemployment? Many will choose to improve their education. 


Meanwhile the Internet has developed into an important adjunct to education. Explicitly:


Youtube (and other video and podcasting and blogging services) provide a lot of brilliant educational material. Unfortunately they also provide an equal or greater amount of well presented false information. For educational purposes there is an urgent need for curation, and to free the material from providers who are subject to so much legal and commercial pressure from various bad actors.


Wikipedia (and other attempts to organize knowledge, such as nLab and kerodon), are a wonderful resource, but they are not oriented to education. For example if you want to understand a particular entry, it will have links to things that you also need to understand, but if you go to those links they are just as complex with just as many links, and not restricted to the level of understanding you need. For educational purposes subjects have prerequisites, and when we have links to material from the prerequisites then we want the exposition to be at the level of that prerequisite. Then, when you go down these rabbit holes, you must come to an end. That is because subjects and prerequisite subjects are organised in a tree structure, and things get simpler as you go down, and there is a limit to how simple you can get. Educational web pages might also have links to other parts of the same course but they will naturally be clearly marked as such.


Let's suppose we do the work, so that we have a wonderful curated collection of educational material, and we have a tree structured curriculum containing links to recommended educational material that covers the course. There are two more things we need for a working education system, which are, in reverse order:

  • Evaluating, in a secure way, that students have acquired the knowledge and skills taught by the course, and providing widely accepted certification of that.

  • Practising the demonstration of the acquired knowledge and skills and receiving feedback and help. 

There are extra problems when the skills to be demonstrated involve real-world interactions, and not just screens. Students will then be limited to particular places even for practice. There will already be a requirement for students to get to particular places for secure evaluation.


Every part of this looks doable. We will assume that we have a collaboration of government and semi-government organizations (such as universities). All the people involved are identified, not anonymous. Identification is naturally from authorization by one of the participating organizations.

Curation of Educational Resources

Some of the people in some of the organizations will be authorized to do curation. This will include all the people preparing courses and curriculums. Where copyright permits the items should be moved to a secure repository. Otherwise a cryptographic hash of the item should be taken so that it can't be changed while staying at the same URL.


The person adding an item indicates why. The main reason will be because it honestly presents the views of a significant number of experts in the field, preferably all of them. Another reason might be that it has historical interest of some sort. The educational level and clarity of presentation would also be assessed.

Curriculum and Course Construction

A curriculum describes the knowledge and skills for a particular subject area at a particular level, and how these should be assessed. It should come with something like a wikipedia entry, except that the links should always point to information in the prerequisites, or perhaps to information from earlier in that same course. This collection of web pages should actually be a very terse course for the curriculum.


A course for a curriculum is a set of curated resources that cover the curriculum, plus example assessments with examples of the successful completion of those assessments.

Assessment

It is envisaged that assessment will be separated from instruction. Instruction can be provided by independent training services. However institutions going to the trouble to produce curriculums and courses, will often be running the course for some students, and providing at least enough assessment for those students. 


Assessment should be secure. Students need to be biometrically identified and the circumstances need to prevent cheating. For example screen based testing should use the assessors screens and should be done in a faraday cage to prevent communication with the outside world.

Training

Separating training from assessment has been quite common. For this to work the curriculum and assessment have to be well defined. The payoff is innovation and flexibility in training. If people already know the subject then they only need to make sure they use the same terminology and notation to get certification.

Summary

A dynamic educational environment can raise productivity, and also make the world a lot safer for democracy when voters need to resist an avalanche of misinformation.


Monday, August 3, 2020

A Nuclear Future for Australia

An Open Letter to CSIRO

The world is on the brink of momentous change. At the same time, the Australian government needs to give the voters a positive message about the future. It is natural for CSIRO to lead at this time.


Nuclear power is going to deliver the cheap, carbon-free high intensity energy that will shape the 21st century. We don't know which SMR (small modular reactor) technology will win, but it is clear that several are close to deployment and there is enormous scope for technological progress. Morrison explicitly said they were not ruling out nuclear. With Indonesia, and many other neighboring countries, going nuclear, there is little doubt we will follow. Leading environmentalists believe it is an essential technology to combat climate change while maintaining and increasing our standard of living.


When I was at CSIRO the public was very anti-nuclear, and we were pleased to escape being united with ANSTO. That is now rapidly changing, and CSIRO will be left behind if it doesn't endorse and support nuclear energy. Deploying and taking full advantage of nuclear power is a multidisciplinary job, so union with ANSTO is now a good step.


The public is ready to hear about the need for disaster preparation. A recurring world-wide disaster is a large volcano erupting, sometimes for years, and significantly reducing sunlight, leading to agriculture failures. This happens every few hundred years on average, the most recent being Mount Tambora in 1815. This is, incidentally, an argument for nuclear power compared to solar. More significantly it is an argument for vertical farming using artificial light, which cheap nuclear power will make affordable. Vertical farming eliminates the need for chemicals, such as insecticides, which have damaged the natural environment. It can benefit from optimal levels of CO2 and just the light frequencies the plants use. Vertical farming is usually shown going up, but it can as easily go down out of sight. Allowing cities to be self-sufficient in basic food production and water purification will strengthen their ability to cope with many sorts of disaster.


Small reactors are also a natural way to power large ships, giving fast, quiet, cheap, and carbon-free shipping. This has the potential to connect Australia to the world, so that we are less reliant on trade with nearby economies such as China. I don't know whether it is practicable for Australia to be involved in manufacturing on that scale, but cheap power plus robot technology seems to open up the possibility.


A look at the map shows that Australia is lacking cities in its North-West. For a truly ambitious project we should build a city there that sits lightly on the land, producing its own water and most of its food, safely destroying its waste and producing no air pollution. I like to think the Aboriginal people will be supportive of this, because it is the blueprint for a world where we can return significant amounts of land to their care.


Further in the future, but clearly in view, is the advance in space technology. While most are thinking about the Moon and Mars, the smart money is on asteroids beyond the frost line, and avoiding deep gravity wells. While this is further in the future, there is an obvious connection to perfecting vertical farming and water purification using nuclear energy


It is in times like these that governments and voters are primed to accept a significant change in direction. Seize the moment.


Sunday, June 7, 2020

Australia: Black Lands Matter



Australia needs to get its own house in order before commenting on racism in America. It is a bit too easy to say "Black Lives Matter", but then not give up anything. But I think recent developments in our understanding of history clearly point to what should be given up.

What we now fully understand is that Aboriginal people, across the whole country, managed the landscape for safety and for productivity. This was effectively farming, and contradicts the view that they were  merely subsisting off land left in its natural state.

After the demise of the megafauna, the Aboriginal people stepped into the breach. The megafauna used to munch and muscle their way through the forests, stopping the understorey building up dangerously. The Aboriginal people developed a system of low level continuous burning to do that job. They also became the top predator, so that kangeroos and other herbivores didn't overgraze.

European settlers and their diseases massively reduced the Aboriginal population. The Sydney area was open woodland when Cook and then settlers arrived. Later, explorers travelling over land saw smoke from fires in all directions. But very soon the dense forests that we are familiar with had taken over, and we new arrivals thought that was the natural state. In fact it had never existed before. Worse still, the Aboriginal practice of burning, though necessary, had had the effect that fire tolerant and fire dependent species were now much more common. We were all setup for the bushfire disasters that have plagued us ever since.

The problems are related and I will propose a solution to both. It needs to be said that the Aboriginal people are not a single legal entity, so we can't just give the forests back to them. Indeed it would not be wise to go that far, because the National Parks are now something that all Australians, and the ancestors who were the ancient owners, would want to keep close to a natural condition.
  • The plan would be gradually expanded. Initially it would cover land where bushfires are likely and dangerous.
  • Those Aboriginal people wishing to actively participate would become the beneficial owners able to: sell hunting licenses, charge for entry or camping, sell natural produce such as kangeroo meat.
  • The Aboriginal people would work with government scientists to plan for returning the forests to a more natural and safer and more productive state.
    • This includes the removal, or at least reduction, of non-native species of plants and animals.
    • Keeping the forest thinned out and with low level vegetation reduced. Cultural burning should be part of this, but sequestering carbon would be better if possible.
  • Those doing the work in the Parks would be paid, proportionately to their involvement. Those with more involvement will also receive more of the benefits.
Training will obviously be an important activity. We want Aboriginal people to be well off, well educated, and honouring their ancestors by caring for the land. Then we will be well placed to advise other countries on race relations. Reducing the bushfires will also be nice.

Wednesday, June 3, 2020

Counting votes in optional preferential

The Australian Senate has optional preferential voting. That means voters can number some candidates (or parties), but not number all of them. As I understand it counting goes like this, assuming you have 6 spots to fill:
  • Divide the number of valid votes 7 (number of winners + 1), rounding down, then add 1 for luck. This is the quota. You need a quota of votes to win a seat.
  • Count votes till someone has a quota. Now only 5 more to go. The rest of the winner's votes (their excess) continues in the count going to lower preferences. Except that doing it that way would be non-reproducible, so actually all the winner's votes continue, but only counting as an appropriate fraction.
  • Except that some votes are now exhausted because they didn't vote below that winner. Now the quota needs to be lowered appropriately, otherwise you might not get enough winners.
  • And so on till you have your 6 winners.
Do they actually reduce the quota? I left a question on Antony Green's web site but didn't get an answer.
To only reduce the quota for subsequent candidates is unfair. The people who vote for the most popular candidates get votes that count less. But going back and changing the quota for previously confirmed candidates could change the count. Maybe they push on with the original quota, hoping they'll get 6 people elected. But that is bad even if it works.
The correct answer is to set the quota to the smallest quota which will elect 6 candidates. So that if you reduce the quota by even one it will lead to 7 candidates getting a quota. The point is that you want to discard the largest number of votes, because that is where the loony single issue supporters are lurking. This is what easily happens when only one person is being elected: almost half the votes can be discarded.
With this counting method, I now think optional preferential Senate voting is ok, minimizing the chances of extremist parties.

Wednesday, April 22, 2020

comments on "Planet of the Humans"

The new movie from the Michael Moore stable, "Planet of the Humans", is available free on youtube: https://youtu.be/Zk11vI-7czE. Everybody should see it.

As we have recently learned from SARS-CoV2, exponential growth is brutal. Also, if something can't go on then it must stop. These things apply to people as well as virus pandemics. That is the basic message of the film.

The movie proposes we solve the problem now with population reduction and much lower consumption. That isn't going to happen. There is an alternative which is two fold:

(a) Take on board the fact that human population exponential growth must stop and build up the social structures that will make that possible. Basically bringing a new person into the world is a deal between the world and the parents, and that needs to be explicit (and fair).

(b) Give ourselves time to get to that point by adopting the one energy source that the rest of nature has no use for: Nuclear Power.

If the movie doesn't kick start a pro Nuclear Green movement than I'll be very disappointed.

A final comment on the movie is this. It is a collection of emotional anecdotes. Anecdotes are a weak form of evidence. The role of anecdotal evidence is to tell you what needs to be seriously and openly investigated. If we've learnt anything from the pandemic, it is the importance of getting the experts involved in a clear and open way, while understanding that they don't always agree, and that they can change their mind.

Wednesday, November 13, 2019

Bushfire prevention: Mechanical Megafauna

Bushfire prevention: Mechanical Megafauna

The megafauna in Australia and America used to munch up the smaller vegetation and defecate fertilizer for the trees. However when humans arrived at those places the megafauna assessed these new small mammals as harmless. Bad mistake. Compare this to Africa where the megafauna evolved alongside humans and they well know to be scared of us and attack us if necessary.

When the megafauna disappeared, the Aboriginal people in Australia discovered the need for controlled burning to maintain the open woodland that was safe from extreme bush fires. This was done on a continuous small scale basis. When European explorers first travelled through the outback they saw smoke from these fires all around.

Left wing governments in Australia and in California have been accused of skimping on controlled burning, contributing to the subsequent disasters. Who can blame governments for disliking controlled burning? It kills wildlife. It is done on windless days but that leads to an unhealthy build up of smoke, affecting local residents. And sometimes the wind picks up and the fire escapes to threaten life and property. And it puts CO₂ into the atmosphere, which seems like a bad idea. The regrowth probably cancels that, but it isn't completely obvious.

I favour attempting to bring back the megafauna, but that is a 100 year project. California and Australia are high tech places, so maybe we can do a high tech solution. I propose the Mechanical Megafauna which will do a better job than controlled burning, and sequester CO₂ as well. The following sci-fi description is one of many ways it might be done.
The giant airship-drone lifted the MechMeg base station from its location and lowered it down carefully between the trees to its next spot. The ground had been mapped with vegetation-penetrating radar. Drones had identified the vegetation at the next stop. 
Everything happened fast after the base station set down. Boston Dynamics robots came quickly out of the base station, cutting down plants and dragging them to the base. Other robots followed to rake up leaf litter and other small stuff. 
The base station processed these by chopping them finely and heating them in a furnace to a very high temperature in a near vacuum. This left a residue that was mostly carbon. It also created a gas with hydrogen and methane which was burnt as part of the energy needed to run the furnace and power the base.
Refueling drones arrived regularly to provide extra hydrogen for the base station and to take away the residual carbon to be sequestered earning carbon credits.
How practical is this? I don't know, but California is very rich.

Tuesday, August 20, 2019

Maths for better Batting

If we look at the bowler's delivery, then at any time the ball is at a specific point and travelling in a specific direction in 3D space. Let's imagine an arrow in space starting at the position of the ball and going in the direction of the ball at that point in time. (This is called a tangent vector of our moving point).

Now imagine the bat moving through space. We'll start by considering the line in the middle of the bat. At any moment in time our bat gives us a line in space, and the motion of the bat defines it's direction. There's a bit of subtlety here, but for our purposes we can pick out a flat plane that the bat is moving in at a particular moment (a tangent plane). When we add the width of the bat, then we get a thickened plane that the bat is moving in.

Now consider the moment when the ball meets the bat. If the ball's arrow is moving across that thickened plane from one side to the other, then any error by the batsmen will result in a miss or an edge. If, at the other extreme, the arrow for the ball is wholly within the plane then an error by the batsman will just mean that the ball hits higher or lower on the bat.

Consider, for example, the sweep shot where the batter uses a horizontal bat to hit the ball close to where it pitches so he doesn't have to worry about the spin. Looks great when it works, but it fails catastrophically. The alternative is to play with an angled bat pointing to the point where the ball pitches, and with the angle of the bat being the angle that the ball bounces up. Now the ball is staying in the bat's thickened plane and though it looks awkward it has a much higher margin for error.

This is harder with leg spin with the ball moving away. Then you have to angle the bat with the handle more away from you than the blade. But if you get the bat handle in front and the blade behind and back cut, then suddenly all is good. Indeed when the batter gets in a muddle, and is forced to back cut the ball to stop it hitting the stumps, they often find that surprisingly easy. It would be exciting to see a batsmen practice this and then do it deliberately and repeatedly.

When the ball is spinning (or swinging) in, then this theory recommends hitting into the spin with a straight bat. I think that is best for defensive shots. Alternatively if attacking then an angled bat hitting to the leg side is your best chance to hit the ball with the balls tangent vector within the bat's thickened plan. This is the slog that even weaker players often succeed with. Not just luck after all.

Sunday, August 18, 2019

Safer red ball cricket

We see that pitches for red ball cricket (3, 4 or 5 days) are prepared that are quite dangerous, to increase the chance of a result. I have an alternative solution.

Wickets fall at a very random rate. Runs are scored at a more even rate. So, instead of having a target of more runs in 20 wickets, the plan is to a target of least wickets to fall to score a set number of runs. You can have as many innings as needed to get those runs.

For example suppose the target for a test match is 500 runs. Then the two teams alternate innings (an innings always counts as 10 wickets) till one team has 500 or more runs. If it is the team batting 2nd then they win because the other team has already lost more wickets. If it is the team batting first that first exceeds 500 runs, then the team batting 2nd knows how many wickets they can afford to lose before they get to 500 to win. Ties will be more common, so maybe have a tie-breaker system, but I don't have a problem with ties.

One nice thing about this scheme is that you can play the game to a finish, however long that takes with rain, without the dangers of matches going for a long time, as used to happen before WWII. Let's have more ties and no draws.

The main objective is that pitches be prepared that don't have the ball rising sharply from just short of a length.

This can be combined with another idea I like: Let the captains make a bid (in runs) for the right to decide who bats first. The side losing the auction starts their innings with the runs they bid.

Wednesday, May 29, 2019

Nuclear for Coal to Oil in Australia

Nuclear for Coal to Oil in Australia

Australia lacks oil reserves, and this is a security issue. A solution is the conversion of coal to oil. The carbon atoms in that oil do not lead to extra CO2 emissions. Oil from elsewhere would otherwise be used.

However the process of converting the coal to oil requires a lot of process heat, which is traditionally provided by burning half of the coal. However to do that would inevitably breach Australia's commitments to reduce greenhouse gas emissions.

The alternative is to use nuclear power. The conversion process is cheaper and more efficient if done at very high temperatures, over 900 degrees C. It turns out that there are modern passively safe reactor designs which provide that level of industrial process heat.

Doing this will be politically very favourable for the current government:

  • Every voter can understand the need for secure access to oil for transport fuels.
  • Many on the Left now understand the need for nuclear power to reduce CO2 emissions, so the introduction of nuclear power will wedge the opposition.
  • Indonesia is making tentative steps towards nuclear power, and many Australians will think that is a good reason for us to do the same.

There are various options to site nuclear power far from most voters. Perhaps the Bunda Cliffs on the southern edge of the Nullabor, which is close to water, but high above a low risk coastline.

Monday, May 27, 2019

Boom, Bust and DNA

Imagine it is boom time for a group of humans. There's lots of food, and time for recreational and romantic activities. What behaviour will favour our genes?

There's no reason to worry about competition from strangers. And strangers are attractive. We plan to have 10 children and 100 grandchildren. If we mix in some slightly different genes then we might produce some offspring that combine good genes of ours with their good genes and make individuals with an advantage. So we're tolerant of strangers, and looking to have offspring with more than one partner.

Now imagine things are bad. Life is a struggle. The population is falling. What behaviour favours our genes now?

People that are like us share more of our genes. People who are different probably don't. And they're competing with us for the limited resources. Maybe we should cooperate with similar people and make sure we get our share relative to those who are different. And note that deaths from fighting are less of a loss to our DNA because deaths are common and it at least leaves more resources for other copies of our DNA. We now hope to have 2 children and 4 grandchildren, or maybe less. And it makes sense to marry our 2nd cousin, or even our 1st cousin.

Wednesday, May 8, 2019

Obvious Things: Nuclear Power for Climate

There are a lot of problems with relying on renewables to cut CO2 production:

But we come back to the fact that the voters hate nuclear power. 

We are currently addressing this by exporting high energy activities (manufacturing) to non-democratic places, i.e. China. But despots have their own fears, and also don't like to annoy their citizens too much. So this may not continue to work. And the rise of robots means that manufacturing may become more uniformly distributed.

The solution has to be:
  • We tell the electorate that we have to do nuclear to address the climate emergency.
  • We are going to do it in a safely remote location and use it to make liquid fuels for transport (hydrogen would be good, ammonia is ok) and/or pump the electricity a long way.
  • We are going to be very open about the planning. No secret stupidity like Fukishima.
And then let's throw a lot of money and expertise at it. Not in the Chinese way where all the eggs are in one basket. Multiple large competing projects. Plus let's start building reactors that are known to work just in case none of the advanced plans work out.

We've been asleep at the wheel. Time to get moving.

Tuesday, May 7, 2019

Obvious Things: Type 2 diabetes

We know that type 2 diabetes is associated with processed food.

We know that type 2 diabetes is associated with the top section of the gut. How do we know this? A treatment for obesity is to do surgery that bypasses that part of the gut. The intention was just to reduce the total size of the gut. But a miracle occurs: if the patient has type 2 diabetes (raised blood sugar), then they are instantly cured! No need to wait for them to lose weight.

So what is the role of the top section of the gut in a normal human primitive diet?

Normally primitive food will come in with the cell walls intact. So it is obvious that the first job, the job done by the top section of the gut, will be to deal with those cell walls. And it will be no surprise if it expects to see cell walls, and uses them to self regulate, and fails to function correctly without them.

And, of course, the characteristic property of processed food is that the cell walls have already been destroyed by industrial processes.

This ain't rocket science. (Whatever happened to "ain't").

Wednesday, April 24, 2019

AutoParliament

AutoParliament
I'd like to support the XR (Extinction Rebellion) movement, but in a way that pushes back against the anti-democratic forces that are keen to take it over (as in this video: https://youtu.be/haGLhlLDCUw -- plans for dismantling our system of government at the end). So I thought I'd create a plan for participatory democracy. Before I start, here is a response to some obvious objections that will come up:
  • "It is too complex". I don't think a simpler plan will work.
  • "It is too confrontational". I think it is crucial to confront the people with bad or misguided motives and sideline them. We can't save the world without confrontation.
  • "It is too technical". I have to admit that the system is designed to attract the technically knowledgeable. We see XR people making totally unrealistic plans. I think the non-technical can join if working in groups with technical support. There are no secrets.
  • "It can't decide anything". That remains to be seen. But what it can determine from the beginning is a consensus view of the relevant facts, and particularly the costs and benefits of various practical actions.
  • "Without anonymity it puts participants at risk to reactionary forces". Absolutely. Participating in this will not be safer than blocking roads and getting arrested. It simply can't be anonymous and function correctly.

Infrastructure

Everything that happens in the AutoParliament is recorded in a replicated log (like a blockchain, but without the massive computing), which can't be changed without the extreme action of going back to an earlier version of the log and replaying some but not all transactions. Access to the log and to updates is available to all, so even if the official servers hosting the log conspire to change it in this way, copies of the log as it was can exist.
Participants have to be associated with public keys to sign their actions. This has to integrated with 2-factor authentication (as in https://en.wikipedia.org/wiki/Universal_2nd_Factor).
The Internet is an essential requirement. But indeed it is essential for the XR movement as well. This is a serious single point of failure. There is an urgent need for a decentralized backup Internet. This shouldn't be too hard, as the Internet is explicitly designed for decentralized operation. I won't address this in this document, as it demands its own independent planning.

Joining

Anyone can join. To join one attends a local meeting of other members, and does the following:
  • Make a video recording where you say your name, approximate address (postcode), say that you are a citizen of [specify country] and the world, and promise to use your membership to address the world's environmental problems.
  • Get (buy) a 2-factor authentication device.
  • Create a record containing the video, the unique id (public key) of the 2-factor device, and the person's own public key, and maybe more.
  • Sign this record with that public key (thus proving the ownership of it).
The signed record then gets added to the replicated log, and the member has joined. Ideally automatic recognition software will quickly discover people joining more than once. I doubt if anyone will attempt it.

Basic Operation

The basic operation of the AutoParliament is a combination of wikipedia and git. There are bills and amendments. Members can vote for or against or abstain for any bills, and can change their vote at any time. If you vote for a bill and for an amendment to that bill, it means you support either variant. If you vote for an amendment, but not for the original, it means you only support the amended version.
At any time there are bills with varying levels of support. Also, as we will see, there are various subgroups of members (caucuses), some self-selected and some automatically generated. Some bills will only be of interest to some caucuses, in which case percentages of those in that caucus will be of interest. External organizations can use a specific caucus (such as their members or supporters) for decision making.
Bills are accompanied by discussion areas where evidence of various sorts can be included.

Endorsements

Each member gets 100 endorsement points and 100 anti-endorsement points to allocate to other members. The member can move them around at any time. This turns into a continuous voting system that works like this:
  1. Each person starts with 1 vote, and gets 0.01 of a vote for every endorsement point.
  2. Now eliminate all the people with the lowest score.
  3. Then multiply everyone's endorsements by their current vote.
  4. And go to 2 and repeat.
This gives everyone a score, which is their highest vote before being eliminated.
This is also done within caucuses to give people a ranking within the caucus.
Members specify how important their caucuses are. The bills that they will normally be invited to consider and vote on will be determined by the current leaders in the parliament and in their selected caucuses. The arguments they will most readily have access to will be those endorsed by leaders. Of course all bills and arguments are available by diligent searching.
Anti-endorsements are also ranked so that anti-endorsement is more significant from people with high endorsement. People with high anti-endorsement scores will attract warning signs on their arguments.
Bills can be introduced arguing for specific people or groups to get endorsement or anti-endorsement and why.

Caucuses

Members are automatically added to geographical caucuses. Groups (or individuals) can create caucuses and determine the memberships.
The system can automatically determine groupings that can then get turned into caucuses. For example we can expect that members will be divided between pro- and anti- nuclear. The system will detect such clusters by similarities in voting and in endorsements. Members of such clusters can turn them into caucuses, so that the system will automatically discover leadership in those groups.

Wednesday, February 20, 2019

Women need to lead to get community action

If you want to sell community action (vaccination or climate change), don't put up a mansplainer talking science. Get an older women with technical leadership and high status to put the message of community solidarity and express anger at the opposition.
E.g. "My grandchildren have been vaccinated. But they might still be vulnerable because vaccines sometimes fail to fully protect. This isn't a problem if everyone is vaccinated because disease can't spread without many potential victims. Anti-vaxxers make all our children vulnerable. They provide enough vulnerable children to allow an epidemic, and some vaccinated children are effected. This is not about individual health, it is about community health. Everyone needs to get behind it."
For Climate Change she might say "Managing the climate is the community's responsibility. There has to be rational evaluation of what needs to be done, and that has to come from the scientific experts looking at all the data, not just a cool day in July. The community that counts is the whole world because we all share the same air. We need to be part of that community. People who don't get behind this shared effort are harming us all, and particularly our children"

Monday, February 18, 2019

Chemicals attacking the microbiome

The microbiome is complicated

Recent research into the health problems being experienced by bees showed that it was not just insecticides causing the problem. What made the bees sick was a combination of small amounts of insecticide with fungicide.

Why would fungicide affect bees? I think the answer is very clear from other research into the microbiome: the cocktail of living things in and on humans and other multicell creatures such as bees.

We used to think bacteria was bad, so antibiotics must be good. Then we learnt that we are home to lots of beneficial bacteria that are damaged by antibiotics. But now we know that the microbiome is a cocktail of bacteria, fungi and viruses. And they are all involved, some more beneficially than others.

Whether we are looking at insect health (which is urgent), or the health of humans, we need to investigate the overuse of a whole range of chemicals, whatever their targets, and even if they are not intended for biochemical effects. And we need to look at the effects of combinations. Given the large (and indeed exaggerated) reaction the general population has to radiation, I believe they can be induced to demand action on this.

[update 2/5/2019: More evidence that fungicide causes health problems: https://www.diabetes.co.uk/news/2019/apr/Additive-found-in-baked-goods-linked-with-possible-type-2-diabetes-risk-91661279.html]

Monday, February 11, 2019

Racism in Tim Flannery's latest book

Tim Flannery is a great bloke, fighting hard to save the world. The last person anyone, including himself, would suspect of racism. But we all want to think well of ourselves, and this very easily extends unconsciously to wanting to think well of groups that we belong to, compared to others.

For Europeans this now embraces Neanderthals, and the hybrids that are descended from them. So in Tim Flannery's book "Europe, A Natural History" we see on page 6 at the end of the Introduction the assertion that the rise of culture resulted from the "hybrid vigour" of the combination of humans from Africa with European Neanderthals. I will easily disprove that hybrid vigour could have anything to do with it. Which shows how tempting such ideas must be to get past the guard of an expert like Tim Flannery.

I have previously written about the genetic advantage of culture (https://grampsgrumps.blogspot.com/2015/02/what-is-culture-for.html). If the genes for culture arose in hybrid populations in Europe, the question arises of how it then appeared in Africa? An easy answer comes along: parallel evolution. This, we remember, was the explanation the Chinese (and others) had for the rise of Homo Sapiens in multiple places. But it was easily disproved by genetic analysis. And even before that, the people who understand evolution know that there is no such thing as parallel evolution. If some substantial and complicated evolutionary change occurs in multiple places at roughly the same time it is because it is all descended from a single point. We can be certain that this is the case with culture. It arose in pure African homo sapiens. It might have taken a slightly different path after hybridization. It is a tempting fancy for us hybrids to regard that slightly different path as superior. If it was a harmless fancy we could let it pass. But it isn't, and we have to reject it.

Friday, September 7, 2018

My Crackpot Theory

[The mirror universe idea is suddenly popular. I notice that others had it before me. Maybe I saw something about it and I later thought I'd invented it?? I don't remember doing so.]
There is matter and antimatter, but luckily for us there is more matter, otherwise the matter and antimatter would annihilate each other leaving nothing but photons. Why is there more matter? I have an answer! Since I'm not an expert in the field, and haven't done due diligence on it, it is, by definition, a crackpot theory. But I like it.
The great Richard Feynman said that antimatter behaves, for computational purposes like ordinary matter travelling backwards in time. Let's take that literally.
Our Universe is expanding from the big bang in accordance with Einstein's equations. Another solution of those equations would be a universe contracting to a reverse big crunch. It doesn't take too much imagination to imagine that immediately before the big bang another universe was coming in to a big crunch. You can regard that as being an earlier part of our Universe, but I want to imagine it as separate. I'll call it the negative universe since it is in negative time if the big bang is at zero.
Particles don't have well defined positions in our quantum universe, which lets them tunnel through apparently insurmountable barriers. So it is possible for some particles moving forward in time from the negative universe to tunnel through to our Universe. And similarly some of our particles moving backward in time (i.e. antimatter) can tunnel through to the negative universe.
So naturally we end up with an excess of matter, and the negative universe ends up with an excess of antimatter. I suggest that in the negative universe, the arrow of time defined by increasing entropy would point backwards. So folk living there would perceive that antimatter as moving forward in time, and perceive the universe as expanding.
It's such a beautiful symmetric picture, it just has to be.
It makes a prediction. In the very early universe particles don't survive long before being annihilated by antiparticles. In the current model where matter is assumed to be slightly different from antimatter, the preponderance of matter happens later. In my model it would appear earlier, so that there is net matter even when the energy level is very high and particles don't last long.

Sunday, April 29, 2018

Bi-quarternions and 4d Clifford algebra

You took a shortcut weeks ago in the program you're writing and now it's biting you, and you know you have to go back and rewrite stuff, but to put that off you start reading Conway and Smith's "On Quarternions and Octonions", and then you wake up in the middle of the night thinking about bi-quarternions. What is the Clifford algebra way of thinking about them?

In Clifford algebra, rotations are given by elements of the even sub-algebra (acting on the vectors to be rotated by the sandwich product). It forms a sub-algebra because the clifford product sums the dimensions so even goes to even. Multiples of the same even element result in the same rotation with the sandwich product, so the degrees of freedom of rotation is one less than the dimension of the even subalgebra.

The grades of the n-dimensional Clifford algebra follow Pascal's triangle and give a total dimension of 2ⁿ. The 0-grade is scalars. There is only one part of the highest grade, so it is called a pseudo-scalar. The 1-grade is the vectors of the base vector space. Orthogonal to each vector is an (n-1)-grade element that is a pseudo-vector which behaves a lot like a vector.

So let's start with 2-d. 1-d is left as an exercise. We have a 2-d vector space. The Clifford algebra consists of: scalars (1-d); vectors (2-d); oriented area elements (1-d, the pseudo scalar). 1+2+1=4. The square by clifford multiplication of the unit area element is the scalar -1. That's suggestive! The even sub-algebra is the scalars plus the area elements. Yes it is the Complex numbers. Because the complex numbers and the vectors are both 2-d it is easy to get them confused. 

In 3-d the Clifford algebra consists of: scalars (1-d); vectors (3-d); bivectors (pseudo-vectors, so also 3-d); oriented volume element (1-d pseudo-scalar). 1+3+3+1=8. The even sub-algebra is the scalars and the bivectors. Yes it is the quarternions. Once again there is potential confusion, this time because the vectors and the bivectors have the same dimensions.

The product of n vectors is called a versor. Up to 3-d there are no Clifford algebra elements that aren't versors. The square of a versor is a scalar. So it makes sense to take the sum of squares of the components of an even subalgebra element, then take the square root to get a norm. With a bit of other calculation we find that they form normed division algebras. This breaks down in 4-d where there are bivectors which are not versors.

In 4-d we have: scalars (1-d); vectors (4-d); bivectors (6-d); trivectors (pseudo-vectors 4-d); oriented hypervolume (1-d pseudo-scalar). 1+4+6+4+1=16. The even subalgebra is the scalars, the bivectors and the pseudo-scalar. But we are told that rotations can also be represented by a pair of quarternions. Here's a way to see two quarternions in the even subalgebra:

We like Clifford algebras because so much can be done without picking distinguished directions to be basis vectors. But somehow we keep finding it convenient to specify a basis, as we will here. Let e1, e2, e3 and e4 be a basis of our 4-d vector space. Now consider just the 3-d subspace formed by e1, e2 and e3. The even subalgebra is the quarternions consisting of the scalar and the bivectors generated by e1e2, e2e3 and e3e1.

This leaves from the bivector basis: e1e4, e4e2 and e3e4. Plus the pseudoscalar e1e2e3e4. Now if we define a new multiplication as the Clifford product times (or divided by) e1e2e3e4 then we get a new model of the quarternions: this time with the pseudoscalar as the scalar. So I've divided the even subalgebra into 2 quarternions.

Well I should check this out more carefully, but I'd better get back to my program that needs fixing.

Monday, June 12, 2017

Logic Programming in Functional Style

[This was also posted on the WombatLang blog, but it is self-contained and might have wider interest.]
[N.B. There is code. In https://github.com/rks987/appendTest I have hand-compiled the example below to an AST, and written a pretty-printer to check it is right. Next step is to write an interpreter for the AST. How hard can that be :-).]

Wombat was designed to be a (mostly) functional programming language with some logic programming capabilities. But it turned out that you can't be half-hearted about logic programming. However the functional roots shine through, giving Wombat a familiar look for most programmers. But behind the scenes, unification is everywhere.

Procedures are also ubiquitous in Wombat. They always have exactly one input and one output. Even things that aren't procedures can act like procedures. In normal functional programming the input is specified, and the output starts out as a hole that the result gets put into. In Wombat both the output and the input are passed to the procedure. Either can be a hole. One or both might be structures which include holes. Consider

(x,y) = f(1,2)

Here "=" causes unification. One might think that the function f will be called, it will return a pair, and unification will then happen. But this is not how Wombat works. Instead (x,y) is unified with f's output, (1,2) is unified with f's input, and execution of f then starts.

Before we look at a more interesting example, some relevant features of Wombat are:
  • An identifier is preceded by backquote when used for the first time. It starts life as a hole, and like all holes it can only be filled in once. `x:Int; x=3 (Explicit typing is optional.);
  • An explicit procedure (closure) is just an expression in braces -- { x+1 } ;
  • A closure's input is $ and its output is `$. The input is commonly a tuple which is unpacked immediately, and $ is never mentioned again -- { $ = (`x,`y); x+y } ;
  • If `$ isn't explicitly unified, then it is unified with the whole expression: {$+1} means {`$=$+1}.
  • A list is given by elements in square brackets separated by spaces. The +> operator adds an element to the head of the list and is invertible.

Here is the classic list append program (using the caseP procedure, rather than the almost identical case syntactic sugar):

`append = {
   $ = (`x,`y); # 2 input lists
   caseP [
       { x=[]; y }
       { x = `hdx +> `tlx;
         hdx +> append(tlx,y) }
   ] ()
};

print( append([1 2],[3 4])); # [1 2 3 4]
[1 2 3 4] = append([1 2],print(`a)); # [3 4] -- print returns its argument
[1 2 3 4] = append(print(`b),[3 4]); # [1 2]

Consider the last line. Execution proceeds concurrently:
  • x is unified with print(`b) and y with [3 4];
    • print is called with its `$ set to the hole x, and its input set to the hole `b. Since it is going to have an effect it has to stall waiting for one or other to be filled. If there were any later effects they would also stall, even if ready to go, because of a lexical ordering requirement.
  • At the same time caseP is called with input set to unit (=()), and output set to the output of the whole procedure (i.e. [1 2 3 4]) since it is the last expression. Now caseP calls all procedures in its list expecting precisely one to succeed. In this case:
    • Closures execute in a sandbox where unifications with holes from outside are tentative and only make it out if the procedure doesn't fail. If the outside hole gets filled in while the closure is executing then the unification is made firm if it agrees with the tentative binding, or the closure fails if it doesn't.
    • So when we look at the first procedure in the caseP, it tentatively unifies x with [], then tries to unify y=[3 4] with `$=[1 2 3 4]. This fails, so that closure fails.
    • At the same time we start the more complex 2nd closure. The first line creates a relationship between the 3 holes: x, hd and tl. The 2nd line then unifies [1 2 3 4] with (hd+>append(tl,y)). this sets hd=1 and unifies [2 3 4] with append(tl,y). So we call append recursively with `$=[2 3 4] and $=(tl,y).
    • The following time that append is called we have `$=[3 4] and then the first closure succeeds (while the 2nd fails), so that when it returns it establishes its parent's y as [3 4], tlx=[] and hdx=2. This resolves the previous line giving x=[2].
    • When this returns the output of print(`b) is unified with [1 2] which in turns sets b to [1 2] and allows the print to proceed.
    • If we weren't going to use b subsequently we could have just written print(_) because _ is always a new hole.