World AIDS Day, 2005

AIDS Can Be Stopped, But It's Not Stopping Yet, And It Won't Stop By Itself

1 December is World AIDS Day 2005.

The 2005 report of the Joint United Nations Programme on HIV/AIDS (UNAIDS) says that the number of people living with HIV/AIDS rose this year to a record 40 million. There were a record number of new infections, about 4.9 million. And about three million people died of AIDS in 2005, including more than 500,000 children.


In addition to the individual human tragedies of suffering, loss and destitution reflected in these grim figures, there is other bad news:

• Only one in ten of those infected with HIV has been tested and knows his or her status.


• The epidemic is gaining strength in Asia, where the toll of death and economic disruption is potentially much higher than in the current centers in sub-saharan Africa. (South Africa has the largest number of people living with HIV/AIDS. Second is India, where the epidemic is just getting started.)


• The outgoing chief of India's official National Aids Control Organization, S.Y. Quraishi, said 70 percent of Indian sex workers either did not know what a condom was or how to use one.


• High mortality among working-age adults erodes productivity and imposes additional costs on businesses. In regions where infection rates are high this may be a significant deterrent to investment, both by private firms, by governments (for instance in education), and by individuals themselves.


• This underinvestment in future generations, together with costs of prevention and treatment, and reduced productivity in industry and agriculture, will reduce the economic growth of many nations, and could even cause the economic collapse of some.


• Refugees from such economic collapse will threaten the stability of affected countries and regions, and their neighbors.


• In many countries, marriage, and women’s own fidelity are not enough to protect them against HIV infection.

  Among women surveyed in Harare (Zimbabwe), Durban and Soweto (South Africa), 66% reported having one lifetime partner, 79% had abstained from sex at least until the age of 17 (roughly the average age of first sexual encounter in most countries in the world). Yet, 40% of the young women were HIV-positive. Many had been infected despite staying faithful to one partner. In Colombia, 72% of the women who tested HIV-positive at an antenatal site reported being in stable relationships. In India, a significant proportion of new infections is occurring in women who are married and who have been infected by husbands who (either currently or in the past) frequented sex workers. (From the 2005 report -- see last year's discussion of AIDS and women's issues.)

On the other hand, there is some good news:

• In several countries HIV infection rates have fallen recently. There have also been reversals of worrying trends in such countries as Brazil and Thailand. These reversals indicate that it is possible to control epidemics using effective prevention programs.


• So although epidemics continue to worsen in many regions, there are demonstrated strategies for stopping HIV/AIDS, if those strategies can be applied.


• Access to HIV treatment has improved over the past two years. There are now more than one million people in developing countries living longer and better lives because they are on antiretroviral therapy.


• In short, "AIDS is a problem with a solution," says Dr. Peter Piot, UNAIDS Executive Director

The key to containing, and someday reversing, the number of new AIDS infections will be the willingness of the developed world to spend tens of billions of dollars to help affected nations implement effective long-term prevention and treatment programs. Given the "disaster fatigue" already affecting donor nations, and their own economic problems associated with the costs of war and welfare reform, what will it take to mount an effective effort?

Even in the United States, with all its resources, the number of new HIV infections has held steady at 40,000 per year for the past five years, and may even be increasing slightly.

The world seems to be willing to accept rampant HIV/AIDS and associated social, economic, and personal suffering in Southern Africa. Will similar crises in Eastern Europe, India or China be as easily ignored?

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Additional Resources

Test your awareness with this HIV/AIDS quiz

UNAIDS site

World AIDS Day is coordinated by Avert.org

Another useful AIDS information site

Excellent report on The Macroeconomics of HIV/AIDS from the International Monetary Fund

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David Wheat's Science In Action site has articles about science and math in the real world, weird science, science news, unexpected connections, and other cool science stuff. There is an index of the articles by topic here.

tags: science, AIDS, HIV, science education, math, education, Science In Action

Epidemic? Pandemic? Why Should I Care?

Should You Be Scared About "Bird Flu"?

We read a lot in the news recently about the threat of a bird-flu pandemic. Is this just media scare, or is it something we should really be worried about? A severe pandemic of a novel, virulent avian influenza would kill millions, stunt economic growth, and maybe even topple governments. However, some of the current scare is overblown. Here are some facts:

A "pandemic" is an epidemic that covers a large geographical area. A "global epidemic".

An "epidemic" is a significant outbreak of an infectious disease, more cases than expected. So malaria in most tropical poor countries is not "epidemic", even though it kills millions of people every year, because this is the "expected" rate. If malaria broke out in Washington, D.C., and killed even ten people, it might be considered a malaria "epidemic". Similarly, about 36,000 people die every year from influenza in the U.S. So an "epidemic" would have to infect a much larger number.

Influenza

The "flu" is caused by a virus. It affects the upper respiratory tract (nose, throat and lungs), and is spread by transfer of virus particles in saliva or mucus droplets, usually expelled in coughs or sneezes. The infection causes fever, body aches, headache, sore throat, fatigue, and coughing and sneezing. Most people will recover in one to two weeks. The disease is life-threatening particularly for the elderly and the young, and for people with underlying medical conditions such as heart or lung disease.

Bird Flu

"Bird flu" or "avian influenza" is a disease of aquatic birds. Sometimes people catch it (if they have been in very close contact with infected birds, usually involved in raising domestic fowl) and if they catch a virulent strain like H5N1 it is very serious. More than half the infected individuals die. Around 100 people have died of bird flu world wide in recent months.

The reason for global concern about bird flu is that influenza viruses can mutate to become more infectious (more easily transmitted). If one of the dangerous (pathogenic = disease-causing) strains of the virus were to mutate to become "human-adapted", so that it could be easily transmitted from one person to another, the stage would be set for a very serious epidemic, or even a pandemic.

The Great Influenza Pandemic of 1918-1919

This global disaster was caused by a novel and deadly strain of avian influenza virus. More than 25 million people died, most of them in poorer countries. In the United States about 28% of the population became ill and more than half a million people died. For comparison, HIV/AIDS has killed about 25 million people over 25 years, while the 1918 pandemic killed the same number in a few months. This is why public health officials are so concerned.

Samples of the 1918 pathogen have been recovered and analyzed. Recently its complete genetic makeup has been published.

What would a flu pandemic be like today?

In contrast to 1918, today we know what causes influenza (a virus) and how it is transmitted. We have some anti-viral drugs (but not many, and they would not be widely available, especially to the poor). We know how to produce flu vaccines, though it takes time to manufacture and administer them. Would these advances enable us to prevent or control a flu pandemic?

Current models of the possible impact of a flu epidemic in the U.S. suggest that between 15% and 35% of the population would be affected, and 100,000 to 200,000 would die ("medium-level" case). Rates of infection and mortality would probably be similar in other developed economies. In poorer countries the impact would be greater. The World Health Organization base case predicts 2 million to 7.5 million deaths world wide.

Political and economic effects could be severe. Restrictions on travel and trade, and reduced business activity due to closed businesses and reduced productivity, would be like a recession. Political instability could develop in places where governments do not appear to be responding effectively or fairly to the crisis. Reduced agricultural productivity and restrictions on food trade could create localized food crises.

Recent disasters have hurt the government in power if their responses are perceived as ineffective (Hurricane Katrina). On the other hand, crises can be used to consolidate political power (September 11th).

Managing A Pandemic Today

Flu epidemics in 1957-1958 and in 1968 killed about 70,000 and 34,000 Americans, respectively. The primary public health tools used to minimize the impact of these outbreaks were vaccination, information, regulation, and more effective treatment.

• Vaccination -- After a new strain of influenza virus emerges and is determined to present a threat of widespread human disease, it takes several months for vaccine targeted at that strain to be developed and manufactured. As the vaccine first becomes available it will be used to protect health care workers and others who are both at high risk of being exposed to the disease and in a position to spread it to others. As larger quantities of vaccine are available they will be allocated by public health services to stop the spread of the disease in particular areas, such as specific cities, military bases, or the like. The standard "flu vaccine" available now is not designed to prevent avian influenza, but is targeted at the normal influenza strains identified earlier this year as most likely to be dominant during the current "flu season".


• Information -- Public health agencies will try to teach people behaviors that will protect them from catching and spreading the disease.
  
  
  • "Hygiene" and "sneeze etiquette" will be strongly recommended. Covering your nose and mouth when you sneeze can reduce the dispersal of airborne droplets of mucus which can potentially carry the virus to others.
  
  
  • Washing your hands frequently can prevent infecting yourself with virus you have picked up, and can help prevent you from spreading the virus to others. Regular soap and water or alcohol hand cleaning solutions work fine. Antibacterial soaps provide zero additional effect.
  
  
  • Masks may be suggested, or even required in some places. One key benefit of a mask is to remind you not to touch your face, thus reducing transmission of virus on the hands. Masks will not filter out viruses, but may prevent dispersal of mucus droplets when you sneeze. Proper disposal of contaminated masks is important. Wearing of masks by the non-infected public may not actually do much to slow the spread of the disease, but it may make people feel more secure.
  
  
  • People with flu symptoms will be encouraged, or indeed in some cases required, to stay at home.
• Regulation -- To reduce the rate of spread of any new, contagious, virulent flu virus several public health measures are likely to be put in place:
  
  
  • Travel from regions where the new strain has broken out will be discouraged or forbidden.
  
  
  • More aggressive monitoring of flu cases will be required, and cases or clusters of cases may have to be isolated (quarantined).
  
  
  • Schools will be closed when the disease breaks out, and some other activities where people gather may be curtailed (e.g. entertainment and sporting events). Some businesses will close or be required to close.
• Treatment -- There are some antiviral drugs which may be used to reduce the severity of the disease, and even some which appear to prevent getting it. Unfortunately, existing flu strains are already evolving resistance to some of these drugs. The drugs would effectively be rationed to be used to protect health-care workers and other essential workers, and to treat the elderly, the young, and others at high risk of complications or death.
  
  Antibiotics do not affect viruses, but many flu deaths are due to secondary bacterial infections such as pneumonia. Antibiotics would be used to treat these cases.

Summary

Flu epidemics will happen in the future, but nobody knows when. Preparations are under way to minimize the social, economic, and public-health impact of the next big one. The best protections against any influenza virus are washing your hands and avoiding getting sneezed on by an infected person. Those most at risk of death in a flu epidemic are those without access to an effective health care system, which includes people in poor countries, people in regions of conflict, and elderly people living alone in developed countries.

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Additional Information

CDC site

WHO bird flu site

U.S. Government site

WHO "10 Things You Need To Know" site

WHO Influenza site

WHO January 2005 threat assessment report

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David Wheat's Science In Action site has articles about science and math in the real world, weird science, science news, unexpected connections, and other cool science stuff. There is an index of the articles by topic here.

tags: science, influenza, bird flu, science education, math, education, Science In Action

Cool Science Sites II

More links to cool science sites I have come across:

A fantiatic flash animation of the Tom Lehrer song "The Elements" is here. Don't miss it!

BBC Radio 4 dramatizations of popular elements Kr, He, Ag, Co, Se, O, As, Hg, I, and Ni, with musical interludes of Tom Lehrer singing his composition "The Elements".

Hyperbolic space crochet models.

The Weirdness of Crowds. Is it really true that if you ask a lot of not-very-well-informed people you can get a very accurate estimate of something? Even something like "In what year did the English Civil War begin?" This site looks at some actual questions and the "crowd's" answers.

Ask Dr. Universe -- Hundreds of questions answered by "Dr. W. S. Universe" at Washington State Univeristy at Pullman, Washington, U.S.A. For example, "Does the Earth weigh the same as it did 10,000 years ago?" (Here is Dr. Universe's answer.)

Female inventors. My favorite is Hedy Lamar, co-inventor of a secure "frequency hopping" radio communication system for torpedo guidance.



A simple, useful, and deep periodic table of the elements.

The science of meteorology on-line. Lots of useful and interesting stuff about weather and other atmospheric phenomena.


Have fun exploring these links. I'll have some more in a few weeks from now.

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The earlier "Cool Science Sites" post is here.

David Wheat's Science In Action site has articles about science and math in the real world, weird science, science news, unexpected connections, and other cool science stuff. There is an index of the articles by topic here.

tags: science, links, science links, science education, math, education, Science In Action

What Is Currency "Inflation"?

Inflation = change in the value of money

A dollar that I had in my pocket in 1960 could have bought a lot more than that same dollar bill would buy today, if I had kept it in my pocket for 45 years. For example, in 1960 that dollar would have bought about ten comic books, about two-thirds of a haircut, about three gallons of gas, ten Cokes, or a movie ticket (in California). Today that same piece of paper (or coin -- but I would get some funny looks trying to plunk down a big, silver Peace Dollar today) would buy about one comic book, one-fifteenth of a haircut, less than half a gallon of gas, one Coke, or an eighth of a movie ticket.

The "nominal value" of that dollar would have stayed the same -- $1.00. But the "purchasing power" of the dollar has changed significantly over time. That change in purchasing power of a unit of money is what we call "inflation".

Economic Definition of Inflation

In economics, inflation is an increase in the general level of prices. In particular, general inflation is a fall in the market value or purchasing power of money within the economy. (This is different from currency "devaluation", which is the fall of the purchasing power of a currency relative to the currencies of other economies.)

The key concept is that the purchasing power of a unit of currency can change.

Prices can also rise for reasons unrelated to the change in the purchasing power of a currency. For example, scarcity of supply may drive up the price of a commodity, such as oil or wheat, due to depletion of oil fields or bad weather in wheat-growing regions. This restricted supply will drive up the price (assuming demand remains about the same). This is not quite the same as general price inflation due to a decline in the value of the currency.

"Real" vs. "Nominal"

Changes in the value of money make it difficult to compare economic statistics, prices, and so on from one period with those from other times. To compare "apples to apples" the currency units from different years have to be converted into equivalent "real" or "inflation-adjusted" units.

For example, the current (nominal, November 2005) price of oil is about $60 per barrel. In 1980 the then-current, nominal price was about $40 per barrel. But in fact the real price of oil was much higher in 1980 than it is today! After adjusting for 25 years of inflation (change in value of the dollar), we see that the price of oil in 1980 was about $100when expressed in September 2005 dollars. Thus the "real" price of oil is nowhere near its historical peak, though the "nominal" price is at a "record high". (Good discussion here.)

What Causes Inflation?

Increase in the supply of money is thought to be one primary reason inflation occurs. If people have more money, the theory goes, they will bid up the price of goods (assuming the supply of those goods is not increasing as fast as the quantity of money in the economy).

There are several ways the supply of money can increase:

Spanish Galleon

• Injection of new wealth into the economy
  
  Gold and silver pouring in from the New World caused inflation in Europe that helped to wreck the economy of Spain in the 16th and 17th centuries. (facts and figures here)
  
  Rapid increases in the value of assets (property or housing "bubbles" or stock market "bubbles" such as the dot-com bubble of the 1990s) give people the feeling that they have more money to spend, so they spend it, often on the same assets that are part of the bubble in the first place. Often they borrow against the increased value of the assets which are part of the bubble.


• Borrowing
  
  Low interest rates or inflated asset prices encourage borrowing, which puts more spendable money in the hands of the borrowers. This cash can be used to bid up prices for things those borrowers want. Credit cards are a tempting source of additional spending power for many people. (Americans currently owe about $800 billion in unsecured credit card debt -- and this is only a fraction of the credit that credit card companies have extended to them.)


• "Printing" of money by governments
  
  Governments are always sorely tempted to overcome budget constraints by spending money they do not have. They can either print additional currency (or in earlier ages debase the coinage by reducing the quantity of gold or silver in it), or they can borrow money which they have no intention of paying back.
  
  Deficit spending is usually a sign of future inflation, since governments rarely pay off their accumulated debts. If it is necessary to make the debt go away the government will either just repudiate it, refusing to pay its creditors, or devalue the currency it was borrowed in, by allowing inflation to decrease its worth, so that the old debt can be paid off with new currency that, while it nominally looks the same, is worth much less.
  
  In addition to actual debt (money borrowed), most governments engage in over-promising -- they make commitments to pay out in the future money that they do not have and probably will not be able to obtain. For example, the United States government currently has public debt of about eight trillion dollars. In addition it has committed to make about $45 trillion worth future social security and other payments to its citizens. Since government income (taxes) will never be able to cover these promised expenditures, there is an almost overwhelming need for the government either to repudiate these obligations or to inflate the currency to make them easier to pay. (News article discussing this)


• Deliberate inflationary policies
  
  Populist political factions sometimes call for deliberate increases in the money supply in an effort to increase prices (for farm products) and reduce the burden of debts. An example is the Free Silver Movement in the U.S. in the last quarter of the 19th century.


• Changes in people's attitudes toward the currency
  
  If people come to believe that the money they possess will become less valuable in the future, due to inflation, they will try to spend it now rather than saving it. Anything that encourages present spending rather than saving increases the amount of money being spent on the (more or less fixed) amount of goods available, which will lead to bidding up of prices (inflation). This process can become cyclical as increasing inflation drives people to save even less and spend any available funds immediately. This may even result in "hyperinflation".

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For Further Information

Good one-page discussion

Inflation calculator

Inflation Conversion Factors for Dollars 1665 to Estimated 2015

Good site on changes in value of money, with excellent links

List of theories on causes of inflation

inflationdata.com -- useful site

Wikipedia on "Inflation"
Wikipedia on "Real vs. Nominal"

Image of Spanish Galleon from this site.

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David Wheat's Science In Action site has articles about science and math in the real world, weird science, science news, unexpected connections, and other cool science stuff. There is an index of the articles by topic here.

tags: science, economics, inflation, science education, math, education, Science In Action

Why Statistics Matter

Big Or Confusing Numbers Require Statistics

We are faced every day with oceans of facts and figures. It is impossible to consider each fact individually, so we use "statistics" to deal with these piles of numbers. "Statistics" are numbers that describe, or summarize, groups of other numbers. The study of this type of analysis and description of unmanageable bunches of data is called "Statistics". How many people attended the Million Man March? (More on crowd numbers at the bottom of this post.)

Statistics Help Us See Patterns

Sometimes these patterns, the conclusions we derive from the raw information, are important. For example:

• Who won the election? (See earlier post Why Doesn't Every Vote Get Counted?.)


• What are the President's poll numbers? (Bush Poll Numbers -- Margin Of Error)


• Is it safe to launch? (Discussion of miscommunication that led to the Challenger disaster; Illustrations are clearer at this pdf site.)


• Who committed the crime? (See "The Case Of The Careless Cab")

Bad Statistics = Bad Decisions

Statistics that are used improperly or misleadingly can cause you to misinterpret the underlying data, leading to bad decisions. (The examples below assume nobody is actually lying. Of course a lot of figures you read are just completely fake, but nobody has bothered to verify them.)

Example 1

Suppose you are listening to three political candidates, and you want to vote for the one which is most likely to work to preserve the environment. Candidate Able says she voted for green legislation 20 times in her last term in office. Candidate Baker says he voted for 80% of the green bills that were proposed during his last term. Candidate Charlie says she has voted for more green legislation than either Able or Baker.

Before you vote you might want to know that:

• Although Able voted green 20 times, she voted against green legislation 100 times. She neglects to mention this.


• Although Baker voted for 80% of the green bills proposed, he voted against the most important and significant bills. He has padded his figures with many minor measures that might be considered environmental.


• Candidate Charlie has been in the legislature for much longer than either Able or Baker. In her earlier terms she voted for many pieces of green legislation, but more recently she has voted against all green measures.

Better keep looking for a candidate friendly to the environment.

Example 2

The average pay at Company A is higher than the average pay at Company B. Which would you rather work for? Before you answer consider that the "average" can be misleading. The CEO at Company A makes ten times the salary of the CEO at Company B, thus "raising the average". All the other workers at Company A earn less than their counterparts at Company B.

So unless you are going to be CEO, you will get paid more at Company B.

If You Don't Understand Statistics, You Can't Spot Bad Statistics

Statistics are widely used in newsmedia, in government reports, and in many other information sources. The purpose should be to make the raw information easier to understand, but often misuse of statistics (sometimes deliberate, sometimes incompetent) causes misinformation or confusion.

Three things to keep in mind when you see statistics or other numbers in media articles or web sites:

• Reporters and their editors believe people like to see "facts" and figures, so they try to find some to put in.


• Reporters (like most other) people don't have a clue about statistics.


• Reporters and most other writers are on a deadline.

Therefor it is up to you to ask:

• What is the source of that number?


• How certain is that number? What is the range of uncertainty?


• What (possibly confused) calculations were used to arrive at that number?

Examples: Crowd Numbers

News stories about demonstrations or other events often include numbers representing the size of the crowd. Nobody actually enumerated the crowd, counting each member, so such numbers are always estimates.

• What is the source of the estimate? (Consider possible bias.)


• What method was used? (Each has its pros and cons.)


• Were the raw data further manipulated? (For example by averaging.)

Here is a good article on crowd estimation. Here is another. Crowds at events in New York City have been estimated by the quantity of garbage they leave behind.

"Counting the March" is an excellent site about using aerial imaging to count the Million Man March.

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Additional Resources

Robert Niles's site on statistics for journalists. Excellent.

A good discussion of misinterpretation of statistics by the media, from Statistics Canada.

Another good site on importance of proper use of statistics

Numberwatch -- "All about the scares, scams, junk, panics, and flummery cooked up by the media, politicians, bureaucrats, so-called scientists and others who try to confuse you with wrong numbers."

At "stats", "We check out the facts and figures behind the news," and unsurprisingly, often find them misleading or wrong.

Nice article on innumeracy among journalists.

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David Wheat's Science In Action site has articles about science and math in the real world, weird science, science news, unexpected connections, and other cool science stuff. There is an index of the articles by topic here.

tags: science, statistics, crowds, science education, math, education, Science In Action

The Earthquake That Changed Europe

The Great Lisbon Earthquake

Two hundred and fifty years ago, at about 9:20 in the morning on All Saints Day, 1755, a magnitude 8+ earthquake occurred, a rupture on the Azores-Gibraltar fracture zone in the Atlantic off the coast of Portugal. The city of Lisbon, the heart of the Portuguese empire and arguably the richest city in Europe, was ruined. Most of the buildings were destroyed, either by the quake itself, by the following fires (which burned for three days), or by the tsunami that surged up the River Taugus half an hour after the earthquake.

Why Lisbon?

Africa rides on one of Earth's great crustal plates, which is slowly moving north. Europe sits on another plate, which is in the way. As the African plate crunches into the Eurasian one, stresses build up. From time to time these stresses cause sudden slips along fault lines (like the one shown in red on the map above), which is what we call an earthquake. (Check here to see animations of the movement of these plates over the eons.) This site on "plate tectonics" shows why earthquakes occur where they do, like the recent one in Kashmir, where the Indian plate is ramming into the Eurasian plate.

Economic Impact

Between 70,000 and 90,000 people were killed in Lisbon, then a city of about 250,000 population. Another 10,000 died in Morocco, also hard hit by the quake. The shaking was felt as far away as the Baltic, and the tsunami reached Britain and North America (although it was only about one meter high by the time it arrived on those distant shores -- in Lisbon it was about six meters high). It is said that the temblor was strong enough in Paris to cause churchbells to ring.

In addition to the loss of life and the destruction of buildings and infrastructure, countless artworks, precious books and manuscripts, and historical records were lost. Lisbon was a rich imperial city (built on the wealth of Portugal's trade in spices -- see related article, slaves from Africa, and gold from Brazil). This Wikipedia article details the destruction. Portugal's days as a leading trading empire with outposts in Asia, Africa and America were already over by 1755, though its colony in Brazil continued to generate wealth. But the ruin of the imperial capital, and the cost of reconstruction, was a further blow to Portugal's status as a great power.

It also affected Portuguese politics of the period. Prime Minister Sebastião de Melo (later Marquis of Pombal), a commoner, took charge and responded effectively after the earthquake (perhaps the first comprehensive disaster response). His power grew, which was a blow to the nobles who had opposed him before the quake. Their opposition festered, and led to subsequent upheaval with the attempted assassination of the King Joseph I, de Melo's patron.

Intellectual Impact

1755 was during the "age of enlightenment" in Europe, a period when rationalism, empiricism and science were beginning to lay the foundations for the modern world. Thus the Lisbon quake was the first in the West to be subjected to scientific inquiry -- the beginnings of seismology. For example, questionnaires were sent to all the parish priests in Portugal to gather information on the local character and impact of the quake. These responses are still archived and used by modern siesmologists. This was the first systematic effort to quantify the effects of an earthquake geographically -- to understand what had happened.

The enormity of the quake profoundly affected many European intellectuals. Immanuel Kant published three works on the quake, drawing on available reports and information, and developing the first modern theory of the causes of earthquakes -- one attributing them to natural rather than supernatural causes.

Just as the 20th century had to come to terms with the Holocaust, so 16th century Western philosophers had to try to understand the great Lisbon earthquake. How could God have permitted such a tragedy, the loss of so many innocent lives, and on a high holy day, just as the faithful were assembling in the churches and cathedrals of Lisbon! The Essais de Théodicée sur la bonté de Dieu, la liberté de l'homme et l'origine du mal of Leibniz (1710) had been an attempt to explain the existence of evil in a world controlled by a benevolent God. Other philosophers objected to this view, in particular Voltaire, who used the tragedy of Lisbon to ridiculeucule Leibnitz's ideas. In his Candide (1759) he places his heroes in Lisbon during the earthquake, after which

. . . Pangloss endeavored to comfort them under this affliction by affirming that things could not be otherwise that they were. "For," said he, "all this is for the very best end, for if there is a volcano at Lisbon it could be in no other spot; and it is impossible but things should be as they are, for everything is for the best."

Disasters Yet To Come

Lisbon had been hit by a significant earthquake in January of 1531, when thousands died. Although the 1755 quake is being commemorated today, are the people of Lisbon, or any other earthquake-exposed city, ready for the next one?

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Here is another interesting site on the Lisbon quake.

The image is in the public domain, from Wikipedia Commons, more info here.

David Wheat's Science In Action site has articles about science and math in the real world, weird science, science news, unexpected connections, and other cool science stuff. There is an index of the articles by topic here.

tags: science, earthquake, Lisbon earthquake, science education, math, education, Science In Action