Introduction

Welcome to Tim Harding’s blog of writings and talks about logic, rationality, philosophy and skepticism. There are also some reblogs of some of Tim’s favourite posts by other writers, plus some of his favourite quotations and videos This blog has a Facebook connection at The Logical Place.

There are over a thousand posts here about all sorts of topics – please have a good look around before leaving.

If you are looking for an article about the Birth of Experimental Science recently published in The Skeptic magazine titled ‘Out of the Dark’, it is available here.

If you are looking for an article about the Dark Ages recently published in The Skeptic magazine titled ‘In the Dark’, it is available here.

If you are looking for an article about the Traditional Chinese Medicine vs. Endangered Species recently published in The Skeptic magazine titled ‘Bad Medicine’, it is available here.

If you are looking for an article about the rejection of expertise published in The Skeptic magazine titled ‘Who needs to Know?’, it is available here.

If you are looking for an article about Charles Darwin published in The Skeptic magazine titled ‘Darwin’s Missing Link“, it is available here.

If you are looking for an article about the Astronomical Renaissance published in The Skeptic magazine titled ‘Rebirth of the Universe‘, it is available here.

If you are looking for an article about DNA and GM foods published in The Skeptic magazine titled ‘The Good Oil‘, it is available here.

If you are looking for an article about animal welfare published in The Skeptic magazine titled ‘Creature Features‘, it is available here.

If you would like to submit a comment about anything written here, please read our comments policy.

 

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What is logic?

The word ‘logic‘ is not easy to define, because it has slightly different meanings in various applications ranging from philosophy, to mathematics to computer science. In philosophy, logic’s main concern is with the validity or cogency of arguments. The essential difference between informal logic and formal logic is that informal logic uses natural language, whereas formal logic (also known as symbolic logic) is more complex and uses mathematical symbols to overcome the frequent ambiguity or imprecision of natural language.

So what is an argument? In everyday life, we use the word ‘argument’ to mean a verbal dispute or disagreement (which is actually a clash between two or more arguments put forward by different people). This is not the way this word is usually used in philosophical logic, where arguments are those statements a person makes in the attempt to convince someone of something, or present reasons for accepting a given conclusion. In this sense, an argument consist of statements or propositions, called its premises, from which a conclusion is claimed to follow (in the case of a deductive argument) or be inferred (in the case of an inductive argument). Deductive conclusions usually begin with a word like ‘therefore’, ‘thus’, ‘so’ or ‘it follows that’.

A good argument is one that has two virtues: good form and all true premises. Arguments can be either deductiveinductive  or abductive. A deductive argument with valid form and true premises is said to be sound. An inductive argument based on strong evidence is said to be cogent. The term ‘good argument’ covers all three of these types of arguments.

Deductive arguments

A valid argument is a deductive argument where the conclusion necessarily follows from the premises, because of the logical structure of the argument. That is, if the premises are true, then the conclusion must also be true. Conversely, an invalid argument is one where the conclusion does not logically follow from the premises. However, the validity or invalidity of arguments must be clearly distinguished from the truth or falsity of its premises. It is possible for the conclusion of a valid argument to be true, even though one or more of its premises are false. For example, consider the following argument:

Premise 1: Napoleon was German
Premise 2: All Germans are Europeans
Conclusion: Therefore, Napoleon was European

The conclusion that Napoleon was European is true, even though Premise 1 is false. This argument is valid because of its logical structure, not because its premises and conclusion are all true (which they are not). Even if the premises and conclusion were all true, it wouldn’t necessarily mean that the argument was valid. If an argument has true premises and its form is valid, then its conclusion must be true.

Deductive logic is essentially about consistency. The rules of logic are not arbitrary, like the rules for a game of chess. They exist to avoid internal contradictions within an argument. For example, if we have an argument with the following premises:

Premise 1: Napoleon was either German or French
Premise 2: Napoleon was not German

The conclusion cannot logically be “Therefore, Napoleon was German” because that would directly contradict Premise 2. So the logical conclusion can only be: “Therefore, Napoleon was French”, not because we know that it happens to be true, but because it is the only possible conclusion if both the premises are true. This is admittedly a simple and self-evident example, but similar reasoning applies to more complex arguments where the rules of logic are not so self-evident. In summary, the rules of logic exist because breaking the rules would entail internal contradictions within the argument.

Inductive arguments

An inductive argument is one where the premises seek to supply strong evidence for (not absolute proof of) the truth of the conclusion. While the conclusion of a sound deductive argument is supposed to be certain, the conclusion of a cogent inductive argument is supposed to be probable, based upon the evidence given. An example of an inductive argument is: 

Premise 1: Almost all people are taller than 26 inches
Premise 2: George is a person
Conclusion: Therefore, George is almost certainly taller than 26 inches

Whilst an inductive argument based on strong evidence can be cogent, there is some dispute amongst philosophers as to the reliability of induction as a scientific method. For example, by the problem of induction, no number of confirming observations can verify a universal generalization, such as ‘All swans are white’, yet it is logically possible to falsify it by observing a single black swan.

Abductive arguments

Abduction may be described as an “inference to the best explanation”, and whilst not as reliable as deduction or induction, it can still be a useful form of reasoning. For example, a typical abductive reasoning process used by doctors in diagnosis might be: “this set of symptoms could be caused by illnesses X, Y or Z. If I ask some more questions or conduct some tests I can rule out X and Y, so it must be Z.

Incidentally, the doctor is the one who is doing the abduction here, not the patient. By accepting the doctor’s diagnosis, the patient is using inductive reasoning that the doctor has a sufficiently high probability of being right that it is rational to accept the diagnosis. This is actually an acceptable form of the Argument from Authority (only the deductive form is fallacious).

References:

Hodges, W. (1977) Logic – an introduction to elementary logic (2nd ed. 2001) Penguin, London.
Lemmon, E.J. (1987) Beginning Logic. Hackett Publishing Company, Indianapolis.

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Reasoning

Rationality may be defined as as the quality of being consistent with or using reason, which is further defined as the mental ability to draw inferences or conclusions from premises (the ‘if – then’ connection). The application of reason is known as reasoning; the main categories of which are deductive and inductive reasoning. A deductive argument with valid form and true premises is said to be sound. An inductive argument based on strong evidence is said to be cogent. It is rational to accept the conclusions of arguments that are sound or cogent, unless and until they are effectively refuted.

A fallacy is an error of reasoning resulting in a misconception or false conclusion. A fallacious argument can be deductively invalid or one that has insufficient inductive strength. A deductively invalid argument is one where the conclusion does not logically follow from the premises. That is , the conclusion can be false even if the premises are true. An example of an inductively invalid argument is a conclusion that smoking does not cause cancer based on the anecdotal evidence of only one healthy smoker.

By accident or design, fallacies may exploit emotional triggers in the listener (e.g. appeal to emotion), or take advantage of social relationships between people (e.g. argument from authority). By definition, a belief arising from a logical fallacy is contrary to reason and is therefore irrational, even though a small number of such beliefs might possibly be true by coincidence.

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From Charlottesville to Nazi Germany, sometimes monuments have to fall

The Conversation

Jose Antonio Gonzalez Zarandona, Deakin University and César Albarrán Torres, Swinburne University of Technology

The recent turmoil over the removal of Confederate statues in the United States invites us to think about the importance of monuments and historical memory worldwide. It also invites us to ask, should statues that represent dark episodes in a country’s history be removed? Or should they be kept as reminders of trauma?

The taking down of a statue of Confederate icon General Robert E. Lee in Charlottesville, Virginia, encouraged groups of neo-Nazis and white nationalists to protest. These extremist groups claimed the decision was a direct attack on their cultural identity and an effort to rewrite history. As we now know, this led to violent clashes between these groups and counter-protestors, and the death of one young woman. It has also led to an unprecedented presidential crisis due to President Trump’s ambiguous statements on the matter.


Read more: Charlottesville, Virginia: the history of the statue at the centre of violent unrest


Following the Charlottesville violence, the far right (or alt-right, as it is also known), has planned as many as nine more rallies in the coming days. In Baltimore, Mayor Catherine Pugh decided to remove Confederate statues overnight, with no publicity, in an effort to ward off political and racial violence in her city, which has witnessed riots in the past. Other Confederate monuments are being removed across the country.

Removing Confederate statues in the US is not unprecedented, nor is it an effort to rewrite history. Rather, it demonstrates a deeper understanding of the nation’s troubled history. For decades, the productive capacity of the southern US depended on the forced migration of people from Africa and their slave labour. The void left by the Confederate monuments speaks even louder than the statues themselves, as the issue of race has gained currency there today.

The Confederate statue removed overnight in Baltimore. EPA/JIM LO SCALZO

The making of meaning

A monument, like the one to General Lee, is a material acknowledgement of a person’s virtue and contribution to the common good. Once history books are written and the voices of victims of dark episodes such as slavery have been heard, it is pertinent to reconsider the moral standing of figures who might have once been considered heroes and are depicted in statues.

Saddam Hussein’s statue falls in 2003.
Wikimedia, CC BY

In Spain, after the death of dictator Francisco Franco in 1975, many towns with statues of Franco decided to remove them. The last Franco monument was removed from the mainland in 2008. The removal of these monuments was also met with the ire of conservative groups.

Perhaps the most famous example of a monument’s removal for political reasons was the spectacular toppling of Saddam Hussein’s statue in Firdos Square in Baghdad in 2003. Symbolically, it marked the end of Iraq’s Baath dictatorship. This event, staged by the US Army and watched in real-time worldwide, represented the end of the regime even more than Saddam’s actual death by hanging in 2006.

Learning from the past

We keep the things that we love the most, but sometimes we also keep the things that reminds us about the horror of the past. Monuments can echo the traumatic events that have shaped our culture, history and civilisation.

A famous example is Memento Park in the outskirts of Budapest in Hungary, where a number of removed statues from the Communist period are kept for visitors to see them and learn about the horrors of the Soviet years. Some also appreciate them as aesthetic objects or a tourist attraction.


Read more: Why tourists go to sites associated with death and suffering


According to the Gregorian dictum, written 1400 years ago by Pope Gregory the Great: images should not be destroyed because they are the books of the illiterate. We learn the mistakes of our past from the images that we make, in the present, of that troublesome past.

Memento Park in Hungary which preserves monuments from the country’s communist period. Wikimedia/Szoborpark, CC BY-SA

When the past becomes poisonous

But some statues have to be removed as a cathartic event, as in the #RhodesMustFall movement in South Africa. At first, it demanded the removal of some statues of Cecil Rhodes, a notorious white supremacist and British imperialist, but the movement became so powerful that it eventually sparked demands for the fall of South African head of state, Jacob Zuma. Removing the statues relieved the accumulated social tensions.

Some statues need to be removed because of their embodiment of venomous ideologies, such as Nazism. For this reason, many symbols of Nazism such as the big swastika in the Zepellinfeld in Nuremberg were completely destroyed after the second world war in Germany. After all, images can work as didactic devices.

The ConversationPerhaps Charlottesville is the first of many cases in which societies will reevaluate past atrocities. Regardless of the outcome, it’s clear that monuments and statues will sometimes help determine the course of history.

Jose Antonio Gonzalez Zarandona, Associate Research Fellow, Heritage Destruction Specialist, Deakin University and César Albarrán Torres, Lecturer, Department of Media and Communication, Swinburne University of Technology

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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What is a species?

The Logic of Science

Alligator snapping turtle (Macrochelys temminckii)

Before you read any further, I want you to take a minute and try to answer the question in the title. Go ahead and write down (or at least think about) the definition that scientists use to determine whether or not two organisms are members of the same species. Now that you have hopefully done that, I am going to burst you’re bubble and tell you that if you wrote down a definition, then no matter what definition you wrote, you’re wrong, or at the very least, incomplete. You see, there is no one universally agreed upon definition of a species. Rather, there are numerous “species concepts” and scientists debate endlessly about what constitutes a species. Further, taxonomic revisions happen constantly and it is extremely common for one “species” to get split up into multiple “species” while other “species” get lumped together into a single…

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Reluctant hero Nicholas Winton, who rescued 669 children from the Holocaust, dies at 106

Why Evolution Is True

Nicholas Winton is not only an unknown hero, but a reluctant one.  A London stockbroker, he flew to Prague in 1938 and, seeing the many Jewish refugees (and prescient about what would happen to Europe’s Jews under the Nazis), he went to work organizing a series of railroad trains to evacuate Jewish children to Britain, one of the few countries that would accept them. Winton saved 669 lives in seven trainloads, but on Sept. 1, 1939, the day Germany invaded Poland, the trains stopped. The 669 children lived, but became orphans, as nearly all their parents died in the concentration camps.

Here’s Winton with one of his beneficiaries:

02wintonobit3-master675 From the NYT: A family picture of Nicholas Winton with one of the hundreds of Jewish children whose lives he saved during World War II. Credit Press Association, via Associated Press

Winton, whose effort was hercuclean—involving bribes, donations, and complicated paperwork—never spoke of his deed after the…

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Nicholas Winton: the man who saved 669 children from the Holocaust

Why Evolution Is True

This morning Matthew Cobb sent me a tweet that reminded me of this story—a story I’d known about but never mentioned. It’s about Nicholas Winton—now Sir Nicholas Winton—a British stockbroker who, on a visit to Czechoslovakia in 1938, managed to launch a rescue operation that ultimately saved 669 children, most of them Jewish, from the Holocaust. Rather than recount the details, just watch the “60 Minutes” clip below, the way I first learned about him. It was filmed when Winton was 104.

In 1988, the BBC, in a surprise event, reunited Winton with many of the children he had saved. Winton was a guest at a television show recounting his exploits, and suddenly the host asked if anybody whom Winton had saved was in the studio. The BBC had brought 24 of those children (80 were living in Britain) to the show, unbeknownst to Winton, and all of them…

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2017 Bendigo Writers Festival

ANZ LitLovers LitBlog

Apologies for being offline this last weekend when we were at the Bendigo Writers Festival – but the internet was playing up at the hotel we stayed at.  I read books instead of blogging, of course! (More about that later, reviews are on the way).

We started Saturday with David Marr in conversation with Sian Gard in a session called Mood Swings. It was about That Dreadful Woman who was the subject of the most recent Quarterly Essay called The White Queen. I’m a subscriber to QE, so I have a copy of it but I’m afraid it went to the Op Shop unread, because I find That Woman and the politics she is associated with, so very depressing.  Marr, however, made an entertaining session of this, though I have to say he had an easy target…

After that The Spouse went to something called Make Mind Music, and that…

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Climate change has changed the way I think about science. Here’s why

The Conversation

File 20170810 4244 oydjjn
Science is a human approach to understanding the world. Nitirak Rakitiworakun/shutterstock

Sophie Lewis, Australian National University

I’ve wanted to be a scientist since I was five years old.

My idea of a scientist was someone in a lab, making hypotheses and testing theories. We often think of science only as a linear, objective process. This is also the way that science is presented in peer reviewed journal articles – a study begins with a research question or hypothesis, followed by methods, results and conclusions.

It turns out that my work now as a climate scientist doesn’t quite gel with the way we typically talk about science and how science works.

Climate change, and doing climate change research, has changed the way I see and do science. Here are five points that explain why.


Read more: Australia needs dozens more scientists to monitor climate properly


1. Methods aren’t always necessarily falsifiable

Falsifiability is the idea that an assertion can be shown to be false by an experiment or an observation, and is critical to distinctions between “true science” and “pseudoscience”.

Climate models are important and complex tools for understanding the climate system. Are climate models falsifiable? Are they science? A test of falsifiability requires a model test or climate observation that shows global warming caused by increased human-produced greenhouse gases is untrue. It is difficult to propose a test of climate models in advance that is falsifiable.

Science is complicated – and doesn’t always fit the simplified version we learn as children. FoxyImage/shutterstock

This difficulty doesn’t mean that climate models or climate science are invalid or untrustworthy. Climate models are carefully developed and evaluated based on their ability to accurately reproduce observed climate trends and processes. This is why climatologists have confidence in them as scientific tools, not because of ideas around falsifiability.

2. There’s lots of ways to interpret data

Climate research is messy. I spent four years of my PhD reconstructing past changes in Australian and Indonesian rainfall over many thousands of years. Reconstructing the past is inherently problematic. It is riddled with uncertainty and subject to our individual interpretations.

During my PhD, I submitted a paper for publication detailing an interpretation of changes in Indonesian climates, derived from a stalagmite that formed deep in a cave.

My coauthors had disparate views about what, in particular, this stalagmite was telling us. Then, when my paper was returned from the process of peer review, seemingly in shreds, it turns out the two reviewers themselves had directly opposing views about the record.

What happens when everyone who looks at data has a different idea about what it means? (The published paper reflects a range of different viewpoints).

Another example of ambiguity emerged around the discussion of the hiatus in global warming. This was the temporary slowdown in the rate of global warming at the Earth’s surface occurring roughly over the 15 year period since 1997. Some sceptics were adamant that this was unequivocal proof that the world was not warming at all and that global warming was unfounded.

There was an avalanche of academic interest in the warming slowdown. It was attributed to a multitude of causes, including deep ocean processes, aerosols, measurement error and the end of ozone depletion.

Ambiguity and uncertainty are key parts of the natural world, and scientific exploration of it.

3. Sometimes the scientist matters as well as the results

I regularly present my scientific results at public lectures or community events. I used to show a photo depicting a Tasmanian family sheltering under a pier from a fire front. The sky is suffused with heat. In the ocean, a grandmother holds two children while their sister helps her brother cling to underside of the pier.

After a few talks, I had to remove the photo from my PowerPoint presentation because each time I turned around to discuss it, it would make me teary. I felt so strongly that the year we were living was a chilling taste of our world to come.

Just outside of Sydney, tinderbox conditions occurred in early spring of 2013, following a dry, warm winter. Bushfires raged far too early in the season. I was frightened of a world 1°C hotter than now (regardless of what the equilibrium climate sensitivity turns out to be).

At public lectures and community events, people want to know that I am frightened about bushfires. They want to know that I am concerned about the vulnerability of our elderly to increasing summer heat stress. People want to know that, among everything else, I remain optimistic about our collective resilience and desire to care for each other.


Read more: Distrust of experts happens when we forget they are human beings


Communicating how we connect with scientific results is also important part of the role of climate scientists. That photo of the family who survived the Tasmanian bushfire is now back in my presentations.

4. Society matters too

In November 2009, computer servers at the University of East Anglia were illegally hacked and email correspondence was stolen.

A selection of these emails was published publicly, focusing on quotes that purported to reveal dishonest practices that promoted the myth of global warming. The “climategate” scientists were exhaustively cleared of wrongdoing.

On the surface, the climategate emails were an unpleasant but unremarkable event. But delving a little deeper, this can be seen as a significant turning point in society’s expectations of science.

While numerous fastidious reviews of the scientists cleared them of wrongdoing, the strong and ongoing public interest in this matter demonstrates that society wants to know how science works, and who “does” science.

There is a great desire for public connection with the processes of science and the outcomes of scientific pursuits. The public is not necessarily satisfied by scientists working in universities and publishing their finding in articles obscured by pay walls, which cannot be publicly accessed.

A greater transparency of science is required. This is already taking off, with scientists communicating broadly through social and mainstream media and publishing in open access journals.

5. Non-experts can be scientists

Climate science increasingly recognises the value of citizen scientists.

Enlisting non-expert volunteers allows researchers to investigate otherwise very difficult problems, for example when the research would have been financially and logistically impossible without citizen participation.


Read more: Exoplanet discovery by an amateur astronomer shows the power of citizen science


The OzDocs project involved volunteers digitising early records of Australian weather from weather journals, government gazettes, newspapers and our earliest observatories. This project provided a better understanding of the climate history of southeastern Australia.

Personal computers also provide another great tool for citizen collaborators. In one ongoing project, climate scientists conduct experiments using publicly volunteered distributed computing. Participants agree to run experiments on their home or work computers and the results are fed back to the main server for analysis.

While we often think of scientists as trained experts working in labs and publishing in scholarly journals, the lines aren’t always so clear. Everyone has an opportunity to contribute to science.

My new book explores this space between the way science is discussed and the way it takes place.

The ConversationThis isn’t a criticism of science, which provides a useful way to explore and understand the natural world. It is a celebration of the richness, diversity and creativity of science that drives this exploration.

Sophie Lewis, Research fellow, Australian National University

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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More attempts to find out what happened to Amelia Earhart

Why Evolution Is True

In my continuing presentation of new evidence for what happened to Amelia Earhart—evidence that always turns out to be wrong—I’ll add this new article from National Geographic:Forensic dogs locate spot where Amelia Earhart may have died.” This summer, an expedition sponsored by National Geographic (which has an obsession with Earhart’s story) as well as The International Group for Historic Aircraft Recovery (TIGHAR), brought a team of researchers, as well as four “bone-sniffing” border collies, to Nikumaroro Island—about 400 miles from Earhart’s reported destination, Howland Island. (She was accompanied by her navigator Fred Noonan.)

Why Nikumaroro? National Geographic says there’s evidence of something there that could be Earhart-related:

TIGHAR’s hypothesis is that, when the aviators couldn’t find Howland, they landed on Nikumaroro’s reef during low tide. Proponents of competing theories argue that Earhart’s plane crashed and sank into the ocean, or that she ended up in the hands…

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Readers’ wildlife photos

Why Evolution Is True

Keep sending in your good photos, folks—I’ll be here all year.

The first two photos come from reader James, but he says to credit the photo to “Lusoman”. It’s a very unusual deer, and here are his notes:

This is a piebald Columbian black-tailed deer (Odocoileus hemionus columbianus) that was born last spring, and which we see regularly in Freeland on Whidbey Island in Washington state. We feed her, as do others in our community, and we’ve given her the nickname “Whitey.” Luckily, the hunters haven’t gotten to her yet. She lives primarily on an area of bluff woodland that is posted for hunting.

I hope nobody shoots her; she’d stand out in the woods like a sore thumb.  The first picture was taken in February, the second in late June. At any rate, this deer shows the condition of leucism, non-albino loss of pigmentation:

The next set…

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Salon disses dismisses Google memo as “biological determinism” that can “slip into eugenicist doctrines”

Why Evolution Is True

UPDATE:  A new piece at the Heterodox Academy by Sean Stevens and Jon Haidt, ‘The Google Memo: what does it say about gender differences?“, examines Damore’s claims about sex differences in ability and preferences by reviewing a great deal of the relevant literature. Some of it supports his claims; other bits don’t. Their general conclusions are below, but you should read their piece:

3) OUR CONCLUSIONS

The research findings are complicated, as you can see from the many abstracts containing both red and green text, and from the presence on both sides of the debate of some of the top researchers in psychology. Nonetheless, we think that the situation can be greatly clarified by distinguishing abilities from interests. We think the following three statements are supported by the research reviewed above:

1. Gender differences in math/science ability, achievement, and performance are small or nil.* (See especially the…

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The ideological opposition to biological truth

Why Evolution Is True

One distressing characteristic of the Left, at least as far as science is concerned, is to let our ideology trump scientific data; that is, some of us ignore biological data when it’s inimical to our political preferences. This plays out in several ways: the insistence that race doesn’t exist (and before you accuse me of saying that races do exist, read about what I’ve written here before: the issue is complex), that there are no evolutionarily-based innate (e.g., genetically based) behavioral or psychological differences between ethnic groups, and that there are no such differences, either, between males and females within humans.

These claims are based not on biological data, but on ideological fears of the Left: if we admit of such differences, it could foster racism and sexism.  Thus. any group differences we do observe, whether they reside in psychology, physiology, or morphology, are to be explained on first principle as resulting from culture rather…

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