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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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 deductive, inductive 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.
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.
An inductive argument is one wherethe 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.
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).
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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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.
Reader Sue Davies sent a report from Australia on how they’re handling the pandemic, and gave me permission to post it. While much of her information comes from two sites (a Guardian Australia site and an Aussie federal government site), the summary and words are her own, and I’ve indented them:
I thought you might like to know how we in Australia are handling the crisis.
The Prime Minister has set up a “National Cabinet” made up of Premiers and Chief Health Officers of all six states and the Northern Territory. This meets daily to make decisions affecting the whole country. All the states are implementing the same laws to ensure that the response is the same everywhere.
Presently the rules are these:
1). No more than two people can congregate outside at any one time (excluding family members). There are stiff on-the-spot fines ($1600) for people caught flouting…
‘In politics one should be guided by the calculation of forces.’ (Stalin at Potsdam)
Alliance is a thorough, insightful and gripping account of the wartime meetings between ‘the Big Three’ Allied leaders – Roosevelt and Churchill and Stalin – which determined the course of the Second World War and set the stage for the Cold War which followed it.
In actual fact the three leaders in question only met face to face on two occasions:
Tehran 28 November-1 December 1943
Yalta, 4-11 February 1945
The third great power conference, Potsdam July 1945, took place after Roosevelt’s death (12 April 1945) and with his successor, former vice-president Harry Truman
There were quite a few meetings between just Roosevelt and Churchill:
Placentia Bay, Canada – 8 to 11 August 1941 – resulting in the Atlantic Charter
First Washington Conference (codename: Arcadia), Washington DC, 22 December 1941 – 14 January 1942
I don’t often tell readers about articles that they simply have to read, but this pair qualifies. Together they’re not terribly short (about 7000 words in toto), but I like to think that my readers have decent attention spans—and the interest in science and politics that makes this Scientific American essay, “Antiscience beliefs jeopardize U.S. democracy” by Shawn Lawrence Otto, mandatory reading. When you finish Otto’s piece, go read the related Sci. Am. piece: “Science in an election year,” which summarizes and rates the Presidential candidates’ stands on 14 critical scientific and technological issues.
In fact, go read them now before you read any other posts on this website.
Otto’s piece not only summarizes the current anti-science strain in American politics, but traces its origins back to the time of the Founding Fathers, who were clearly pro-science (Jefferson and Franklin come to mind). From those…
One of the big mysteries of paleobiology is where complex life (i.e., animals) came from, and what the earliest animals looked like. The first traces of life that we have go back about 3.7 billion years ago, but those are cyanobacteria (the so-called “blue green algae”). The first animals with “true cells”—the eukaryotes, go back to about 1.8 billion years. But then there’s a huge gap of 1.2 billion years before we have the first traces of more complex multicellular life (putative sponges, jellyfish, and ctenophores) near the beginning of the Ediacaran period (571-541 million years ago). That fauna contained a number of bizarre and enigmatic forms.
Many of those forms went extinct without issue at the beginning of the Cambrian (about 545 million years ago). But since there was not a separate and later creation that led to modern animals (we know this from molecular data), some of the…
I’ve been kvetching about the unavailability of commercial products that you can use to kill coronavirus on packages, countertops, steering wheels, and so on. For of what use are recommendations to sterilize everything if you can’t buy the disinfectant?
In response, my doctor, Alex Lickerman, sent me a list of 287 commercial products, recommended by the Environmental Protection Agency, that you can use as sanitizers to kill coronavirus. Some of these must surely be available. I for one would like to use isopropyl alcohol and/or Lysol, but neither seems to be available (I can’t order the former via lab channels as the University is shut down for that.) But if you click on the screenshot below you’ll find an extensive list that surely cannot all be sold out.
If you know of some products that are available in pharmacies and grocery stores, and are not sold out or hoarded, by…
A group at Oxford produces a website called “Our World in Data“, and they have excellent coronavirus coverage, including not just data compilations but also information of practical use. They have good to great visualizations, with very good explainers.
The data are updated daily based on WHO figures. It has a single set of authors and vetted data source. Their “Growth of cases” (third set of charts in) I find particularly useful, as it is able to show changes in the dynamics– the fact that in China and South Korea they have passed the peak. (This, of course, does not rule out a second wave of exponential growth later, as has happened with flu pandemics.)
Screen shot of growth of confirmed cases from Our World in Data, 2020 03 17 1146 GMT -5. (The “+0 new” for the United States is probably due to…
Elizabeth Warren’s withdrawal from the Democratic Presidential race wasn’t surprising. After all, she hadn’t won a single state after Super Tuesday, and she finished third even in her own home state of Massachusetts—a real embarrassment. It’s clear why she withdrew, as by Thursday she didn’t have a snowball’s chance in hell of getting the nomination, so why waste the money and effort?
But there’s no shortage of theories about why she didn’t succeed. I know why I bailed on her when I voted on Wednesday, even though she was once my favorite candidate. As I said a few days ago, I lost some enthusiasm for her as the campaign proceeded as she seemed slippery (as did Bernie, at least about his healthcare funding!). Still, I would have voted for her in the Illinois primaries, but that became a moot point after Super Tuesday and the race narrowed to Sanders vs…
Warning: This blog post contains strong and sometimes challenging imagery, including depictions of slavery, violence and suffering.
When I visited the Baroque Britain exhibition at Tate Britain I was surprised that there was a Content Warning at the entrance to the second room. This warned us that some of the images were disturbing and might upset visitors. Specifically, a massive painting by Benedetto Gennari the Younger which shows black people in collars and chains. Slaves, in other words.
Portrait of Hortense Mancini, Duchess of Mazarin by Benedetto Gennari the Younger (1674)
A handful of other paintings show rich people – men and women – being served or accompanied by black servants, but this is the only one where the black people (all boys, I think) are wearing very obvious metal slave collars round their throats.
This is the second warning notice I’m aware of Tate putting…
By Jill Hosken, Celebrant (with contributions from Tim, Stephen and John Harding)
Being born in 1924, Raie Harding grew up in very different times and throughout her long life she has witnessed more technological, political, economic and social changes than are ever likely to be experienced in one lifetime.
Raie was an only daughter born to Tom and Ruby Purvis and the family initially lived in South Caulfield before moving to Middle Brighton. With her Dad being an engineer and in regular work, despite the depression years Raie had a happy and settled childhood – nevertheless it is unlikely she could ever have envisaged the wonderful, rich experiences life had in store.
Her secondary years were at the prestigious MacRobertson Girls’ High, a selective entry school but with the unfolding of WW2 she left early and after completing business studies attained work at the Victoria Hotel in Little Collins St. In addition to her office duties, Raie helped organise events and tours to entertain the visiting US military officers (including swing bandleader Artie Shaw), many of whom were based in Melbourne – organisational skills which came to the fore later in life.
She’d known Bruce Harding, a local Brighton lad, since her early teens and when he returned from war service, they reconnected and ultimately married in the Melbourne Grammar School Chapel in 1948. The newlyweds bought a double block opposite Rickett’s Point, on the corner of Lang St and Point Ave surrounded by dirt tracks and ti-tree for the princely sum of £182/10. Despite the shortage of building materials, with Bruce being a qualified builder, he was able to construct what was to become the family home.
Over the ensuing eight years, they were blessed with three sons Tim, Stephen and John and even though they were pretty good as boys go, Raie still had her hands full!! Nevertheless, she relished her role as a mother and nurturer and always supported her three sons in their endeavours ensuring they had the best of opportunities and many wonderful experiences.
With four active males under her roof, Raie craved some girl time and was known to occasionally “borrow” a neighbour’s daughter, Sue McGregor who shared on hearing of Raie’s passing, how as a young girl, she loved opportunities to be in Raie’s company, learning to cook and sew.
Beaumaris back then was very isolated – there were no local shops and before getting a car, Raie would catch a bus to Black Rock to do the weekly shop. However, she was one of the first women in the neighbourhood to have a car, a Land Rover – probably the first SUV to be seen in the area!
The neighbours were like extended family – the boys related how each afternoon, the Point Avenue mothers would gather at one another’s home on rotation, vegies in hand and join together over a sherry as they prepared their respective evening meals. The neighbourhood kids enjoyed the freedom of playing in the bush or riding their bikes or going to the beach – the only condition being they were home by 6 for dinner.
Her sons appreciate the long leash they were given but also knew there were expectations such as good manners, respect and ethics which stood them all in good stead for the future.
In 1956, the year John was born, Bruce and Raie purchased “Shady Acres” in Macclesfield – a farm at which they spent many a weekend or school holidays getting back to basics with no power and no mod cons. Here they grew Angus beef cattle, Angora goats, pine trees and later on wine grapes – they also had horses which all the boys rode – a skill that Raie never quite mastered, despite having lessons and so when friends visited, often after enjoying a BBQ lunch they’d all head off for a ride, Raie was very unimpressed to be left cleaning up!
Later Raie and Bruce purchased a holiday home at Metung where sailing on the lakes and many happy times were enjoyed by all. When “Shady Acres” underwent some remodelling in the 80’s, Raie, being a very gifted seamstress sewed all the drapes, bedspreads and even the new upholstery for the lounge suite.
At home she also sewed, enjoyed creating a welcoming garden and for a time, having a neighbour who was a very talented artist and potter, Raie took up pottery. Raie also was a wonderful support to Bruce in his business and many a dinner party was enjoyed at their Beaumaris home by colleagues and friends alike. She was the consummate hostess and a gifted cook – she embraced cordon bleu cooking (very in vogue in the 70’s) and had all the fancy cookbooks of the era.
The boys recalled how their Mum would do a practice dinner party dinner on a Tuesday – always a new taste sensation. Raie also gave dedicated support in Bruce’s community work with the Beaumaris RSL and Legacy to which they gave a great deal of time supporting war widows and their children.
Perhaps it was through this that piqued Raie’s interest in Social Work – this together with her desire to prove, in the very male dominant world of the time, that despite limited education opportunities, women had a brain. So, aged 46, Raie enrolled in an Arts Degree at Melbourne Uni and Tim related how he enjoyed sitting in Politics lectures next to his Mum. In 1978 Raie proudly graduated with a Bachelor of Arts and Social Work.
Over the years she and Bruce enjoyed a number of overseas trips and a well-remembered one was when she visited Steve whilst he was in London during the 70’s and they then toured Europe together.
After completing some extensive renovations (including electricity), Bruce and Raie moved to “Shady Acres” living there until Bruce died after a short illness in 1996. After coming to terms with this new reality, Raie moved back to Middle Brighton where she enjoyed a full and active life. She could often be found at Victoria Golf Club where through her 40 years of membership many strong friendships were forged
Playing golf into her early 80’s Raie then moved on to Bridge and enjoyed lunches and gatherings at Victoria with friends. She loved any opportunity to go to the movies, enjoyed shopping – was always on the hunt for a bargain and loved hopping on the train to visit Steve, Susie and the girls in Adelaide!
Raie had a very loving relationship not only with her three sons Tim, Steve and John, but also with her daughters-in-law Lisa and Susie. She was very grateful for the help they gave her, especially towards the end of her long life.
Three years ago, acknowledging she needed support and after doing her own research Raie made the decision to move to Karinya Grove Aged Care in Sandringham where she has been well cared for.
As she always had in the past, Raie continued to participate in and enjoy all the family gatherings and celebrations – birthdays, Christmases and retirements along with Carl and Jayne’s wedding. Raie particularly enjoyed visits from her beloved grandchildren – Georgia and Kate all the way from England, as well as from William and Angus. She loved hearing about their lives and various achievements.
She especially enjoyed celebrating her 95th birthday last October at Karinya with family and friends in attendance. All would agree, even with her decline in acuity in these past years Raie always made the best of things and did what she could to ensure those around her felt loved, connected and cared for.
“Lastly I must say thank you for the great privilege and all the joy and pleasure that I have experienced as Mum to my three wonderful boys and and their families. I leave you with all my everlasting love and the wish that most of the hopes and aspirations you may have had for the great journey of life that we began together will be realised.’ – Raie Harding