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.

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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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The intractable problem of North Korea

Why Evolution Is True

As you may know, North Korea, the world’s most repressive nation, is about to test a new nuclear weapon. Within two decades, says the New York Timesin an article published today, the DPRK will have the ability to deliver nuclear weapons via intercontinental missiles. That means the U.S. will be in danger.

So far there’s no stopping that country. Weapons development has been faster than predicted, sanctions haven’t worked, and China doesn’t have the stomach to apply the pressure it should, perhaps because they actually want the U.S. to be threatened.  Trump is making threatening noises, but really, what can he do? If he takes unilateral action, North Korea will simply destroy Seoul, only a few miles south of the border. There’s little doubt of such a reprisal, except that it will be a suicidal move by Kim Jong-un.  But the man is not rational, so who knows?

The…

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The Art of War, by Betty Churcher

ANZ LitLovers LitBlog

Last week, with Anzac Day approaching, it seemed a good time to browse through Betty Churcher’s magnificent tribute to the artists who depict war.  The Art of War was written to coincide with a TV program on SBS, produced by Film Australia, and I had not long ago stumbled on my copy at Bound Words in Hampton St Hampton.  But the day after I started drafting this review, my father unexpectedly died, and I forgot about this post until tonight, the eve of Anzac Day 2017.  So for now, I’m just going to focus on what I’ve read of the book, just Chapter One.

The Art of War is a paperback, but it is full-sized and printed on quality glossy paper so  the reproductions of the paintings are superb.  (You need to click the links to see most of them, because of copyright).

This is the blurb:

The wars that have been…

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RFK Jr and vaccine safety – using a bad study to come to bad conclusions

Source: RFK Jr and vaccine safety – using a bad study to come to bad conclusions

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Step up for science at the crossroads for humanity

The Conversation

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Science and technology have helped us picture that we all live together on a single world. NASA / Bill Anders

Alan Duffy, Swinburne University of Technology

Globally, science is at a crossroads.

In the USA, a protectionist stance from policymakers and an increasingly inward focus have resulted in a restive public, giving rise to protest across spheres and sectors. This has sent ripples across the world, including in Australia.

While the practice of scientific inquiry is apolitical, science and technology themselves are a litmus test for a healthy political system. The ability to pursue science and technology freely and without favour serves as a measure of political freedom, and their applications provide the tools to preserve and enhance it.

In providing a universal language that transcends culture, science bridges communities across the globe. Its pursuit is impossible without collaboration and connection, and the benefits it yields serve our species as a whole. Consider transformational technologies such as the internet and smartphones, or the inspirational and pioneering recent discoveries of gravitational waves and liquid water on Mars.

Scientific research also allows countries to work together, and succeed together, in global arenas separate from political interest. It builds common ground and unites us against the common enemies of humankind – disease, hunger, poor sanitation, disadvantage and catastrophic threats to our environment.

Now, though, the international litmus test of policy and political support for scientific and technological advancement internationally is creeping dangerously towards the downside. It is vital that we do not forget the long list of advantages and benefits that come from collaborating internationally, from cooperating across cultures to learn, and from sharing our knowledge with the world – they far outweigh the risks or dangers.

Allowing free movement of researchers, empowering institutions and universities to attract the best and brightest from around the world, and allowing these women and men to conduct their work unimpeded by political machinations will benefit us all.

This isn’t the stuff of ivory towers. The potential for science to improve our health, wellbeing, and environment are recognised and supported by the average Australian voter. This week a poll conducted by the College of Arts and Social Science at the Australian National University showed that 82% of Australians want science to play a greater role in politics, and more than two-thirds say government funding is the best mechanism for this to occur.

On 22 April 2017, hundreds of thousands – perhaps even millions – of people will take to the streets globally to March for Science. Whether they march or not, Australians should ask themselves if they will stand strong in the future to defend and support the positive impact science and technology has had in their lives. Science is not just for scientists.

If decision makers understand the value we place on science and technology, and the gifts we reap from their discoveries and applications, we can look forward to an exciting and productive future.

We’re standing at the crossroads, and science can’t be alone in taking the first step in defence of creating and applying knowledge. The Australian people must also step out and stand up for science, so that together we can forge a strong path towards a healthier, safer, more empowered future for our species and our planet.

This article was coauthored by Kylie Walker, chief executive of Science & Technology Australia

Alan Duffy, Associate Professor and Research Fellow, Swinburne University of Technology

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

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Jeff Sessions implies that a Hawaiian judge’s decision isn’t relevant to America

Why Evolution Is True

Jeff Sessions is the Attorney General of the United States, which means he’s our chief law enforcement officer. Nevertheless, he doesn’t seem to recognize that Hawaii is part of the United States, as valid a state as any other.  Nevertheless, he didn’t seem to recognize that a Federal Court ruling in Hawaii, overruling Trump’s second executive order on immigrants, has the force of law. When Federal judge Derrick K. Watson of Hawaii issued the block, Sessions (who voted to confirm Watson) put his metatarsals in his mouth:

CNN reports:

Sessions told “The Mark Levin Show” earlier this week that he was “amazed that a judge sitting on an island in the Pacific can issue an order that stops the President of the United States from what appears to be clearly his statutory and Constitutional power.”

Called out on this gaffe, Sessions didn’t take it back:

“I don’t know that…

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Peter Doherty: why Australia needs to march for science

The Conversation

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March for Science events will be held across the world on April 22 2017. From www.shutterstock.com

Peter C. Doherty, The Peter Doherty Institute for Infection and Immunity

The following article is adapted from a speech to be delivered at the Melbourne March for Science on Saturday 22 April, 2017. The Conversation

The mission posted on the March for Science international website states:

The March for Science champions robustly funded and publicly communicated science as a pillar of human freedom and prosperity. We unite as a diverse, nonpartisan group to call for science that upholds the common good and for political leaders and policy makers to enact evidence based policies in the public interest. The March for Science is a celebration of science.

To me, it seems the reason concerned people across the planet are marching today is that, at least for the major players in the English-speaking world, there are major threats to the global culture of science.

Why? A clear understanding of what is happening with, for example, the atmosphere, oceans and climate creates irreconcilable problems for powerful vested interests, particularly in the fossil fuel and coastal real estate sectors.

Contrary to the data-free “neocon/trickle down” belief system, the observed dissonance implies that we need robust, enforceable national and international tax and regulatory structures to drive the necessary innovation and renewal that will ensure global sustainability and a decent future for humanity and other, complex life forms.

Here in Australia, the March for Science joins a global movement initiated by a perceived anti-science stance in Donald Trump’s administration.

Trump’s 2018 budget proposal

In the USA, President Trump’s proposed budget for 2018 incorporates massive cuts to the National Science Foundation (NSF), National Oceanographic and Atmospheric Administration (NOAA), the United States Environmental Protection Agency (EPA) and the National Institutes of Health (NIH).

And, though it in no sense reflects political hostility and deliberate ignorance, British scientists are fearful that Brexit will have a terrible impact on their funding and collaborative arrangements.

How does this affect us in Australia? Why should we care? The science culture is international and everyone benefits from progress made anywhere. NOAA records, analyses and curates much of the world’s climate science data. A degraded EPA provides a disastrous model for all corrupt and regressive regimes.

Science depends on a “churn”, both of information and people. After completing their PhD “ticket”, many of our best young researchers will spend 3-5 years employed as postdoctoral fellows in the USA, Europe and (increasingly) the Asian countries to our north, while young American, Asian and European/British scientists come to work for a time with our leading scientists.

The proposed 2018 US President’s budget would, for example, abolish the NIH Fogarty International Centre that has enabled many young scientists from across the planet to work in North America. In turn, we recruited “keepers” like Harvard-educated Brian Schmidt, our first, resident Nobel Prize winner for physics and current Vice Chancellor of the Australian National University (ANU).

We might also recall that – supported strongly by Prime Ministers JJ Curtin and RG Menzies – the ANU (with 3 Nobel Prizes to its credit) was founded as a research university to position us in science and international affairs.

Not a done deal, yet

What looks to be happening in the US is not a done deal.

The US political system is very different from our own. The Division of Powers in the US Constitution means that the President is in many respects less powerful than our PM.

Unable to introduce legislation, a President can only pass (or veto) bills that come from the Congress. Through to September, we will be watching a vigorous negotiation process where separate budgets from the House and the Senate (which may well ignore most, if not all, of the President’s ambit claims) will develop a “reconciled” budget that will be presented for President Trump’s signature.

How March for Science might help

The hope is that this international celebration of science will cause US legislators, particularly the more thoughtful on the right of politics, to reflect a little and understand what they risk if they choose to erode their global scientific leadership.

There are massive problems to be solved, along with great economic opportunities stemming from the development of novel therapies and new, smart “clean and green” technologies in, particularly, the energy generation and conservation sector.

Ignoring, or denying, problems does not make them go away. Whether or not the message is welcome, the enormous power of science and technology means we can only go forward if future generations are to experience the levels of human well-being and benign environmental conditions we enjoy today.

There is no going back. The past is a largely imagined, and irretrievable country.

Peter C. Doherty, Laureate Professor, The Peter Doherty Institute for Infection and Immunity

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

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Tobruk 1941, by Chester Wilmot

ANZ LitLovers LitBlog

Doug Allan 1970

I don’t usually read military history, but I couldn’t resist this latest release in the Text Classics series.  Tobruk 1941 interests me because The Offspring had a great-uncle who was a Rat of Tobruk.  Uncle Doug Allan, who died in 1985, was a gentle, kind-hearted soul, generous to a fault and with the typical laconic Aussie sense of humour, but this apparently ordinary Aussie Bloke was also a hero, the like of which we’ll never see again.

Early in 1941, Australian troops captured Tobruk from the Italians: it was an important victory because it was Mussolini’s stronghold on the Libyan Coast.  Bordered by pitiless desert, Tobruk was a strategic fortress because it had a deep-water harbour on the eastern Mediterranean.   Rommel’s Afrika Corps quickly arrived to reclaim it and so began a 241-day siege beginning in April and not lifted until November of that year.  Germany had successfully stormed through Europe using Blitzkrieg tactics, and the Afrika Corps had never been defeated.  Tobruk…

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Where Do We Go Next? — IV

Footnotes to Plato

Polling survey[for a brief explanation of this ongoing series, as well as a full table of contents, go here. Note: this is the last entry in this 27-part series]

What do philosophers think of philosophy?

I am about to wrap up my tour of what philosophy is and how it works, which has taken us throughout these seven chapters to examine subjects as disparate as the Kyoto School and Quineian webs of beliefs, the history of progress in mathematics and the various theories of truth as they apply to the explanation of scientific progress. Before some concluding remarks on the current status and foreseeable future of the discipline, however, it seems advisable to pause and reflect on what philosophers themselves think of a number of issues characterizing their own profession.

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Facts are not always more important than opinions: here’s why

The Conversation

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The message over the doorway to London’s Kirkaldy Testing Museum. But don’t be too quick to believe the facts and dismiss the opinions. Flickr/Kevo Thomson, CC BY-NC-ND

Peter Ellerton, The University of Queensland

Which is more important, a fact or an opinion on any given subject? It might be tempting to say the fact. But not so fast… The Conversation

Lately, we find ourselves lamenting the post-truth world, in which facts seem no more important than opinions, and sometimes less so.

We also tend to see this as a recent devaluation of knowledge. But this is a phenomenon with a long history.

As the science fiction writer Issac Asimov wrote in 1980:

Anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that “my ignorance is just as good as your knowledge”.

The view that opinions can be more important than facts need not mean the same thing as the devaluing of knowledge. It’s always been the case that in certain situations opinions have been more important than facts, and this is a good thing. Let me explain.

Not all facts are true

To call something a fact is, presumably, to make a claim that it is true. This isn’t a problem for many things, although defending such a claim can be harder than you think.

What we think are facts – that is, those things we think are true – can end up being wrong despite our most honest commitment to genuine inquiry.

For example, is red wine good or bad for you? And was there a dinosaur called the brontosaurus or not? The Harvard researcher Samuel Arbesman points out these examples and others of how facts change in his book The Half Life of Facts.

It’s not only that facts can change that is a problem. While we might be happy to consider it a fact that Earth is spherical, we would be wrong to do so because it’s actually a bit pear-shaped. Thinking it a sphere, however, is very different from thinking it to be flat.

Asimov expressed this beautifully in his essay The Relativity of Wrong. For Asimov, the person who thinks Earth is a sphere is wrong, and so is the person who thinks the Earth is flat. But the person who thinks that they are equally wrong is more wrong than both.

Geometrical hair-splitting aside, calling something a fact is therefore not a proclamation of infallibility. It is usually used to represent the best knowledge we have at any given time.

It’s also not the knockout blow we might hope for in an argument. Saying something is a fact by itself does nothing to convince someone who doesn’t agree with you. Unaccompanied by any warrant for belief, it is not a technique of persuasion. Proof by volume and repetition – repeatedly yelling “but it’s a fact!” – simply doesn’t work. Or at least it shouldn’t.

Matters of fact and opinion

Then again, calling something an opinion need not mean an escape to the fairyland of wishful thinking. This too is not a knockout attack in an argument. If we think of an opinion as one person’s view on a subject, then many opinions can be solid.

For example, it’s my opinion that science gives us a powerful narrative to help understand our place in the Universe, at least as much as any religious perspective does. It’s not an empirical fact that science does so, but it works for me.

But we can be much clearer in our meaning if we separate things into matters of fact and matters of opinion.

Matters of fact are confined to empirical claims, such as what the boiling point of a substance is, whether lead is denser than water, or whether the planet is warming.

Matters of opinion are non-empirical claims, and include questions of value and of personal preference such as whether it’s ok to eat animals, and whether vanilla ice cream is better than chocolate. Ethics is an exemplar of a system in which matters of fact cannot by themselves decide courses of action.

Matters of opinion can be informed by matters of fact (for example, finding out that animals can suffer may influence whether I choose to eat them), but ultimately they are not answered by matters of fact (why is it relevant if they can suffer?).

Backing up the facts and opinions

Opinions are not just pale shadows of facts; they are judgements and conclusions. They can be the result of careful and sophisticated deliberation in areas for which empirical investigation is inadequate or ill-suited.

While it’s nice to think of the world so neatly divided into matters of fact and matters of opinion, it’s not always so clinical in its precision. For example, it is a fact that I prefer vanilla ice cream over chocolate. In other words, it is apparently a matter of fact that I am having a subjective experience.

But we can heal that potential rift by further restricting matters of fact to those things that can be verified by others.

While it’s true that my ice cream preference could be experimentally indicated by observing my behaviour and interviewing me, it cannot be independently verified by others beyond doubt. I could be faking it.

But we can all agree in principle on whether the atmosphere contains more nitrogen or carbon dioxide because we can share the methodology of inquiry that gives us the answer. We can also agree on matters of value if the case for a particular view is rationally persuasive.

Facts and opinions need not be positioned in opposition to each other, as they have complementary functions in our decision-making. In a rational framework, they are equally useful. But that’s just my opinion – it’s not a fact.

Peter Ellerton, Lecturer in Critical Thinking, The University of Queensland

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

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How I became a philosopher

Footnotes to Plato

Aristotle, the first scientist-philosopher

As some of my readers know, I have an unusual background. I began my academic career as an evolutionary biologist (Master’s at the University of Rome; Doctorate at the University of Ferrara, Italy; PhD at the University of Connecticut), switching to philosophy (PhD at the University of Tennessee) later on. A number of people, even recently, have asked me why. Here’s the answer, which I offer not (just) as a self indulgent piece of personal biography, but as a reflection on the academic world and the role of serendipity in life. It may be of interest to some, especially young students who are considering a career in either field.

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