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.

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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Cultural appropriation: can minorities appropriate the culture of other minorities?

Why Evolution Is True

This is the kind of question that arises when you adopt full-blown intersectionalism. It’s apparently been decided that it’s okay to culturally “appropriate up“, i.e., Chinese people can wear jeans, and Africans suits, but it’s not okay to “appropriate down“, so that white people can’t wear cornrows or play jazz—at least not without explicitly acknowledging the borrowing and, as this article by Bianca Lambert, a freelance beauty writer, maintains, studying all the nuances of that borrowing.

The article at hand is, of course, at PuffHo, and the answer to the question in the title is a clear “yes: it’s appropriation for minorities to adopt black culture.” But it’s apparently not wrong for blacks to adopt Hispanic or Hindu culture. Click on the screenshot to read:

Most of the article is the usual culture-protection and calling-out of appropriators, and not worth commenting on again; but the thesis…

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Nobel Prize in Physiology or Medicine goes to two Americans and a Brit for work on adaptation of cells to varying levels of oxygen

Why Evolution Is True

This just in: the Nobel Prize for Physiology or Medicine was awarded to the three people below (click on screenshot to go to the Nobel site):

I don’t know these researchers, nor much about their work, but I’ve put an informative video below (which shows you how the Prizes are announced, and what garnered one this year), and this is from the CNN report:

The 2019 Nobel Prize in Medicine has been jointly awarded to William Kaelin Jr., Sir Peter Ratcliffe and Gregg Semenza for their pioneering research into how human cells respond to changing oxygen levels.

Announcing the prize at the Karolinska Institute in Stockholm on Monday, the Nobel committee said that the trio’s discoveries have paved the way for “promising new strategies to fight anaemia, cancer and many other diseases.”

The importance of oxygen has long been established, the committee explained, but how cells adapt to changes…

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Vestigial limb muscles in human embryos show common ancestry—for the gazillionth time

Why Evolution Is True

There are three kinds of vestiges that constitute evidence for evolution (the sub-claim of that theory that modern species share common ancestors), and I mention all three in Why Evolution is True:

1.) Vestigial traits that persist in modern species but either have no adaptive function or a function different from that served in their ancestors. The vestigial ear muscles of humans are one, the flippers of penguins (functional, but not for flying in the air) is another, the coccyx in humans (sometimes with attached “tail muscles” that can’t move it) is a third.

2.) Vestigial genes that are functional in our relatives (and presumably in our ancestors) that have been inactivated in some modern species. There is no explanation for these “dead genes” save that they were useful in ancestors but aren’t useful any longer. Examples are “dead” genes that code for egg yolk proteins in humans (but don’t…

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1/3rd of Auckland measles patients are hospitalised

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A NYT interview with Bill Maher

Why Evolution Is True

This Sunday’s New York Times Magazine has a long interview with Bill Maher (click on screenshot below)—complete with footnotes, something I haven’t seen in the NYT.

I’ve always been a big fan of Maher: there are in fact few things he’s said on his show that I don’t agree with. I suppose it’s because both he and I criticize both the Right and the Left, and Maher, one among many, has suffered for doing that. The Left wants to be immune from criticism by others who profess to be Left, but Maher is not only a Leftist, but an incisive social critic.  And now I learn that he’s a huge Beatles fan as well. What’s not to like? And so, to celebrate International Blasphemy Day, treat yourself to a read. I’ll put a few excerpts below.

By the way, in the interview Maher defines political correctness as “the elevation of…

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Readers’ wildlife photos

Why Evolution Is True

Do send in your photos if you have some good ones!

Today’s batch comes from biologist Adam Greer, who says, “Here are some wildlife photos to boost your inventory – all taken from various places along the Gulf Coast of Mississippi and Alabama.”

Bald eagle (Haliaeetus leucocephalus):

Cape May warbler(Setophaga tigrina):

Northern Cardinal chick (Cardinalis cardinalis):

Great egret (Ardea alba):

Great horned owl (Bubo virginianus):

Green heron (Butorides virescens):

Indigo bunting (Passerina cyanea):

Mississippi kite fledgling (Ictinia mississippiensis):

Prothonotary warbler (Protonotaria citrea):

Red-headed woodpecker( Melanerpes erythrocephalus):

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The dirty dozen: twelve myths about e-cigarettes

Simon Chapman AO

Advocates for e-cigarettes often appear to display cult-like adherence to a set of beliefs. Like beings possessed of inviolable truths, they repeat these as often as possible. Here are 12 articles of vaping faith, and why they are highly questionable.

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  1. E-cigarettes are 95% less harmful than smoking

The “95% less harmful” claim was first made in a 2014 report chaired by Professor David Nutt, notable and perhaps unique in publicly declaring that e-cigarettes are “the most significant advance [in medicine] since antibiotics”. The report was written by a selected group of 12 individuals who each were asked to estimate the relative harmfulness of e-cigarettes and other nicotine containing products compared to cigarettes. Their Big Number was repeated in a 2014 report by Public Health England, which again endorsed it in a 2015 update where it once again cited the Nutt report as a source, but again provided no…

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The Castle by Franz Kafka (1926)

Books & Boots

They rushed to the [telephone], asked for the connection – how eager they were about it! in externals they were absurdly docile – and inquired if K. could come with them next morning into the Castle. The ‘No’ of the answer was audible even to K. at his table. But the answer went on and was still more explicit, it ran as follows: ‘Neither to-morrow nor at any other time.’

‘When can my master come to the Castle?’
‘Never,’ was the answer.

Plot

In The Trial Joseph K is ‘arrested’ (although, in fact, allowed to remain entirely free to continue going about his business as he wishes) and spends the rest of the increasingly fraught story having encounters with Court officials, friends, lawyers and other advisers who (he hopes) can help him make his case to the Court and clear his name. But there never actually is a trial, Joseph K never gets to…

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Book Review

A Blog on Winston Churchill

Faith in appeasement, the central tenet of British foreign policy throughout the 1930s, remained strong among the most devout long after it had been exposed as entirely bankrupt. Even as it lay in tatters with the German military massing on the Polish frontier for the invasion of Poland in the late summer of 1939, the virtually disloyal British ambassador to Berlin Sir Nevile Henderson recommended the Polish government concede to Hitler’s demands, while in London R.A.B. Butler, member of parliament, despaired that the British Foreign Office was displaying an unwarranted “absolute inhibition” to pressure the Poles to negotiate. After the German invasion of Poland, Prime Minister Neville Chamberlain and his government prevaricated one last time before finally declaring war on Germany.

Appeasement was “the attempt by Britain and France to avoid war by making ‘reasonable’ concessions to German and Italian grievances.” The long list of “reasonable concessions” when finally catalogued included…

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The Great Wall of China by Franz Kafka (1917)

Books & Boots

my investigation is purely historical

I remember this story giving me a funny feeling when I read it as a teenager because of the heady, sweeping vision of history it gives you. I was too young to realise that any ‘history’ it contains is used for purely aesthetic reasons, to feed the purposes of the parable and of Kafka’s distinctive take on human existence.

The Great Wall of China imagines what it was like to be one of the builders of the Great Wall. It is told from the point of view of an articulate member of the generation who were raised to build it, trained to build it, and indoctrinated to build it, a man from a southeast Chinese province ‘almost on the borders of the Tibetan Highlands’.

The first half of the text describes the excited and patriotic ‘spirit of the times’, the narrator being lucky enough to have…

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