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 2,300 posts here about all sorts of topics – please have a good look around before leaving.

If you are looking for an article about Skepticism, Science and Scientism published in The Skeptic magazine titled ”A Step Too Far?’, it is available here.

If you are looking for an article about the Birth of Experimental Science 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 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 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.

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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. Reason is the application of logic to actual premises, with a view to drawing valid or sound conclusions. Logic is the rules to be followed, independently of particular premises, or in other words using abstract premises designated by letters such as P and Q.

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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8 common excuses for not being COVID-19 vaccinated, and what you can say that might help

Simon Chapman AO

Geriatrician Kate Gregorevic has tweeted a very useful thread of 8 common fears and excuses she has heard from those who are vaccine hesitant, together with her responses. These are so useful. Please copy to those in your life who may benefit from reading these.

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Pseudoprofundity

by Tim Harding

Most skeptics are familiar with the term ‘pseudoscience’, which means non-scientific activities masquerading as science. Examples include astrology, alchemy, so-called ‘alternative medicine’ and ‘creation science’.

Less well-known is the term ‘pseudoprofundity’, which means claptrap masquerading as profound wisdom. Deepak Chopra springs to mind, when he uses pseudoprofound terms such as ‘quantum healing’ and ‘dynamically active consciousness’.  

‘Love is only a word’ is a more general example of pseudoprofundity which Daniel Dennett calls a ‘deepity’ – the pretension of depth. This is a phrase which sounds like it contains a great depth of wisdom by virtue of being perfectly ambiguous. The philosophical blogger Jonasan writes that on one level it is clearly false that love is only a word. ‘Love’ is a word, but love itself is not (the inverted commas are important). The fact that ‘love’ is a word is also trivially true. We are thus left with a statement which can either be interpreted as obviously false or trivially true.  Jonasan notes that by failing to exercise our powers of analysis on this statement we end up thinking about both meanings together, rather than separating them and perhaps seeking clarification about which meaning is intended. This gives an illusion of profundity.

Stephen Law has pointed out that you can also achieve this effect without the need for an ambiguity in meaning. Ordinary trivially true platitudes such as ‘death comes to us all’ can be elevated to the level of profound insight if enunciated with enough gravitas. Likewise, one can take the other side of Dennett’s deepities – that of self-contradiction – and use it without even needing the trivially true side. Law again gives us one of the finest examples in ‘‘sanity is just another kind of madness’. It sounds profound doesn’t it? Except that sanity cannot be a form of madness because they are defined as opposites.

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Adelaide Writers Week: Twilight of Democracy, with Anne Applebaum and Sally Warhaft

ANZ LitLovers LitBlog

The Twilight of Democracy is a rather depressing title for a festival session, but I’ll take any opportunity to listen to Sally Warhaft, especially when she’s in conversation with a Pulitzer Prize winner!

This is the session blurb:

Pulitzer prize-winning author and historian Anne Applebaum deconstructs the psychology and motivations of today’s crazed conspiracy theorists and populists in Twilight of Democracy, an incisive examination of the longstanding struggle between democracy and dictatorship. Drawing on experience and high-level relationships forged across Europe and America, and an exemplary understanding of contemporary and historical politics, Twilight of Democracy is a confronting and illuminating analysis of a polarised world.

Warhaft began by asking about Applebaum’s departure in style from her previous books.  She’s an historian, she said, but she could not write this book as a history because it’s not possible to be entirely objective when you’re living through the moment and you’re part…

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Mandating masks rapidly and dramatically increases mask use: before law 7%, after 97%

Simon Chapman AO

Following the development of a cluster of COVID-19 cases in late December 2020 in Sydney’s northern beaches region, the NSW government introduced a requirement for mandatory mask use on all public transport, retail shops, cinemas and theatres from midnight on January 2, 2012. Fines ranged from $200 for individuals, $1000 for small businesses and $5000 for corporations.

With the ebbing of cases, this requirement was narrowed a few weeks later, with masks remaining mandatory on public transport and in close-contact occupational settings like hair salons, barbers, massage parlours and nail bars.

Throughout 2020, the government had resisted extensive and often impassioned calls from many public health experts, the state political opposition and many members of the public for masks use to be mandatory in public indoor settings and public transport.

Well before masks were mandated, on July 28, 2020 I spent 90 minutes on the platform of my local railway…

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Pseudo-profundity vs. philosophy

J'ai une plume

The work of philosophers is often misperceived by people of other professions thanks in part to the existence of a great many other things which call themselves philosophy. The sort of ‘wise’ aphorisms which can be read in magazines, heard at lifestyle conferences and spouted by one’s elders at the dinner table rarely stand up to any form of analysis, but nevertheless are seen by a great many people as the currency in which philosophy deals.

“Love is only a word” is an example of this pseudo-profundity which Daniel Dennett calls a ‘deepity’. A deepity is a phrase which sounds like it contains a great depth of wisdom by virtue of being perfectly ambiguous. On one level it is clearly false that love is only a word. ‘Love’ is a word, but love itself is not (inverted commas are important). The fact that ‘love’ is a word is also trivially…

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Soviet Jokes About Living Under Oppression

Science Matters

The Soviet people lived under a regime where private life, ideas and opinions were banished from public expression by state media.  Now the USA has state media rivaling the USSR, only difference is ambiguity whether the media runs the state or vice-versa as in Soviet days.  In any case, Russians and others under that regime voiced their resistance by sharing jokes at the expense of the autocrats.  Wikipedia provides some instructive examples for Americans in the days ahead.

A judge walks out of his chambers laughing his head off. A colleague approaches him and asks why he is laughing. “I just heard the funniest joke in the world!”
“Well, go ahead, tell me!” says the other judge.
“I can’t – I just gave someone ten years for it!”

Q: “Who built the White Sea Canal?”
A: “The left bank was built by those who told the jokes, and the right…

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Love in a Cold Climate, by Nancy Mitford

ANZ LitLovers LitBlog

This was an enjoyable romp with which to end my reading year.  1001 Books You Must Read Before You Die compares Nancy Mitford to Jane Austen.

Well, I don’t know about that.  I’m not sure that the novel would bear re-reading as Austen’s novels do, but FWIW this is what 1001 Books has to say:

Mitford’s novels, like those of Jane Austen, focus on the small social manoeuvrings of an exclusive family and their “set”; like Austen, she uses fond but mocking satire to gently send up the family, even while encouraging the reader to care about its fortunes. (1001 Books You Must Read Before You Die, ABC Books 2006, p.450)

The blurb encapsulates the slight plot:

Love in a Cold Climate is a wickedly funny satire, brilliantly lampooning upper-class society. When Polly, a beautiful aristocrat, declares her love for her married, lecherous uncle – who also happens to…

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Tribal truth fallacy

During the 2020 US presidential election campaign, one of the starkest visual differences between Trump and Biden supporters was in the wearing of masks. Most Biden supporters appeared to wear masks, whereas most Trump supporters didn’t.

Even during Trump’s announcement of his nomination of Judge Amy Barrett to the US Supreme Court, very few people in the White House Rose Garden were wearing a mask. Worse still, some of the guests were seen hugging and kissing each other. 

As a result, the White House has become a COVID-19 ‘hotspot’ or super-spreader location, with seven attendees at the Justice Amy Barrett nomination announcement testing positive for coronavirus – even President Trump and the First Lady. More people caught the virus at the White House election ‘celebration night’. 130 Secret Service agents have also tested positive.

It is clear that at least some, if not most, of Trump supporters refuse to wear masks on political grounds. They seem to associate mask wearing with what they perceive to be ‘liberal’ pro-science attitudes. It is also possible that some Biden supporters might wear masks as a form of visual political opposition to the Trump supporters. In either case, this is irrational tribal behaviour. 

A similar phenomenon may be occurring in the climate change debate. Some beliefs against human causes of climate change may be genuinely (but mistakenly) held on the basis of personal interpretation of the evidence. But at least some of the far-right wing opposition is due to a perception of climate science being some sort of left-wing plot against fossil fuel industries.

The far left is not immune from such irrational tribal behaviour either. At least some of the opposition to GMOs and vaccines seems to be based on ideological opposition to large agribusinesses and the pharmaceutical industry, rather than on evidence-based health concerns.

Another example is where some atheists oppose the idea of free will simply because Christians believe in it.  (This is despite the fact that prominent atheists such as Professor Daniel Dennett also believe in free will).

The tribal truth fallacy lies not in the falsity of beliefs about mask wearing, climate change, GMOs, vaccines or free will per se; but in the basis for these beliefs being identification with one’s own tribe or opposition to a rival tribe.

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Readers’ wildlife photos

Why Evolution Is True

Send in your photos, but make sure they’re good ones. Thanks!

Today was have some lovely landscapes from reader Bill Zorn. His captions are indented.

Sand Dunes, Colorado:

The Narrows, Utah:

Altamaha River, Georgia:

Monument Valley, Utah:

Jekyll Island, Georgia:

Jekyll Island, Georgia:

Linville Gorge, North Carolina:

Irwin Creek, Colorado:

Reeds, Georgia:

North Fork of the Virgin River, Utah:

These images were made using a Linhof Master Technika 2000 camera, Fuji Velvia film. I sent the film to a lab, and printed these on Ilfochrome. These are scans from the transparencies.

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Nobel Prize in Physics goes to three for showing that formation of black holes is predicted by relativity theory

Why Evolution Is True

This morning the Karolinska Institute awarded the 2020 Nobel Prize in Physics to two men and a woman—Roger Penrose, Reinhard Genzel, and Andrea Ghez—for work on black holes.  As the press release notes:

Three Laureates share this year’s Nobel Prize in Physics for their discoveries about one of the most exotic phenomena in the universe, the black hole. Roger Penrose showed that the general theory of relativity leads to the formation of black holes. Reinhard Genzel and Andrea Ghez discovered that an invisible and extremely heavy object governs the orbits of stars at the centre of our galaxy. A supermassive black hole is the only currently known explanation.

Penrose got half the prize, with Genzel and Ghez sharing the other 50%.

My Nobel Prize Contest (see here and here) is already a big flop this year, with nobody guessing even one person from each of…

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