Tag: Logic

Crimes Against Logic: Exposing the Bogus Arguments of Politicians, Journalists, and Others

A lot of our day is spent trying to convince people of something. To do this we often make arguments as to why our product or service is better, or, more commonly why our own opinion is right and yours is wrong. But few of us understand the art of argumentation.

Crimes Against Logic: Exposing the Bogus Arguments of Politicians, Priests, Journalists, and Other Serial Offenders, a book by Jamie Whyte, “aims to help fill the gap left by the education system,” in the ways that our reasoning can go wrong. “The logic equivalent of one of those troubleshooting guides in your car or computer manual.”

Errors in logic are not visible.

When a car breaks down, anyone can see that it has even if he knows nothing about how cars work. Reasoning is different. Unless you know how reasoning can go wrong, you can’t see that it has. The talking doesn’t stop, no steam emerges from the ears, the eyes don’t flash red.

Until Google invents a device that exposes our errors in reasoning we need to rely on ourselves. And most of us don’t know a lot about the ways that reasoning can go wrong. Whyte argues that we’ve become a nation of suckers.

Schools and universities pack their minds with invaluable pieces of information— about the nitrogen cycle, the causes of World War II, iambic pentameter, and trigonometry— but leave them incapable of identifying even basic errors of logic. Which makes for a nation of suckers, unable to resist the bogus reasoning of those who want something from them, such as votes or money or devotion.

Often, when we can’t tell good logic from bad we turn to cynicism, “discounting everything said by anyone in a position of power or influence.”

But cynicism is a poor defense, because it doesn’t help to tell good reasoning from bad. Believing nothing is just as silly as believing everything. Cynicism, like gullibility, is a symptom of underdeveloped critical faculties.

The Irrelevant Right

Jack has offered some opinion— that President Bush invaded Iraq to steal its oil, let’s say—with which his friend Jill disagrees. Jill offers some reasons why Jack’s opinion is wrong and after a few unsuccessful attempts at answering them, Jack petulantly retorts that he is entitled to his opinion.

The fallacy lies in Jack’s assumption that this retort is somehow a satisfactory reply to Jill’s objections, while, in fact, it is completely irrelevant.

Jack is just changing the subject to one of rights, not addressing the issue. Here is a simple way of putting it.

The fallacy lies in Jack’s assumption that this retort is somehow a satisfactory reply to Jill’s objections, while, in fact, it is completely irrelevant.

We consider our opinions to be sacred.

Many people seem to feel that their opinions are somehow sacred, so that everyone else is obliged to handle them with great care. When confronted with counterarguments, they do not pause and wonder if they might be wrong after all. They take offense.

So the next time someone says you have a right to your own opinion, mentally go back and see if they are addressing your argument or just changing the subject. If you really want to have fun, you can ask them what duties do rights impose on others?


When my sister was fifteen, she thought she had fat thighs. Occasionally, she would demand to know, “My thighs are fat, aren’t they?”

“No darling,” my parents would reply, “you have nice thighs; you’re a beautiful girl.”

Well, that confirmed it. “You’re just saying that!” was the constant refrain as my sister took our parents’ protestations to the contrary to confirm all her worst fears.

My sister was committing the Motive Fallacy. She thought that by exposing our parents’ motives for expressing an opinion— to make her feel better and shut her up— she had shown the opinion to be false. But she hadn’t. It is perfectly possible to have some interest in holding or expressing an opinion and for that opinion to be true. A man may stand to gain a great deal of peace and quiet from telling his wife that he loves her. But he may really love her nevertheless. It suits most to believe they are of better than average looks, and at least 44 percent of the 90 percent who believe this actually are. My sister’s legs were not fat. In other words, you don’t show someone’s opinion false just by showing that he has a motive for holding it.

This happens when billions of dollars are at risk too.

The motive fallacy is another way that we end a debate. You don’t actually refute the positions of the other person, you simply change the subject.

First, you are discussing some issue, such as whether my sister has fat thighs, and then, after the fallacy is committed, you find yourself talking about the motives of those involved in the discussion. Perhaps this is why the fallacy is so popular. It turns all discussions— be they about economic policy, religion, or thighs— into discussions about our alleged motives and inner drives.


The fallacy lies in confusing two quite different kinds of authority. There is the kind of authority your parents, football referees, and parking attendants have: the power to decide certain matters. For example, your parents have the power to decide when you will go to bed. Hence, in answer to the question “Why is 8:00 P.M. my bedtime?” the answer “Because I say so” is quite right; your parents are, quite literally, the authors of your bedtime. But it is not up to them whether or not Jesus was conceived without the help of sexual intercourse. Mary’s being a virgin at the time of Jesus’s birth is beyond the will of your parents, or indeed anybody else’s (with the possible exception of Jesus’s parents). So your father’s answer “Because I say so” is quite wrong when the question is “Why should I believe in the virgin birth?” The matter exceeds the scope of his parental authority.

Yet, there is another metaphorical sense of “authority” on which the answer “Because I say so” is sometimes reasonable, even when literal authority is absent, namely, the expert kind of authority. If someone is an expert on some subject (or an authority on the topic, as it is often put) then his opinion is likely to be true— or, at least, more likely to be true than the opinion of a non-expert. So, appealing to the opinion of such an authority— i.e., an expert— in support of your view is perfectly OK. It is indirect evidence for your opinion.

We can’t all be experts on everything. When laypeople sit around debating evolutionary biology, quantum physics, developmental economics, and the like, as the government’s reckless education policies mean they increasingly do, one of the best pieces of evidence likely to be put forward is simply “Because Nobel laureate Joe Bloggs says so.” …

The Authority Fallacy should now be clear. It occurs when the first literal type of authority, whereby someone has the power to make certain decisions, is confounded with the second metaphorical type, whereby someone is an expert and so likely to be right about some matter of fact.

Relating this to government and democracy, Whyte points out the power of the people also comes with the ability to make the wrong choices.

All democratic politicians agree that ultimate political authority lies with The People. On other matters they may disagree. One may think private schools an abomination, the other that the state should have no role in education. Each tries to convince the public that her view is right, knowing that popular opinion will decide the matter. But, “decide the matter” does not mean determine who is right. The People cannot do that; no one can by mere decision make a state monopoly on education superior to a private system, or vice versa. Public opinion decides the matter only insofar as it chooses which policy will be adopted. And the public is perfectly capable of choosing the inferior policy. If it were not, if popular opinion were invariably correct, then politicians would have no serious leadership role to play; government could be conducted by a combination of opinion pollsters and bureaucrats.

Spotting this fallacy is easy, simply ask yourself if the source offered up as an authority is indeed an expert on the matter in question. If not, ask them to explicitly walk you though the argument.

Crimes Against Logic goes on to introduce you to other logical fallacies that you and others use every day. If you’re interested in improving your own arguments and spotting errors in the arguments of others, this is a good starting place.

Not All Good Arguments Are Logically Sound

Some interesting thoughts from James Gray on whether all good arguments are logically sound. Understanding why helps us appreciate good arguments.

Proof that not all arguments are logically sound
An argument against the belief that all good arguments are logically sound is the following:

  1. At least some good scientific theories were proven to be false.
  2. If at least some good scientific theories could proven to be false, then not all good arguments are logically sound.
  3. Therefore, not all good argument are logically sound.

Premise 1 – Is it true that “at least some good scientific theories were proven to be false?” Yes. For example, I think Newton’s theory of physics is a good example. It was believed that Newton’s theory of physics was complete and could predict any physical motion, but it failed to predict the motion of Mercury. However, Einstein’s theory of physics was able to predict the motion of Mercury and is now considered to be a better (and more complete) theory of physics.

Premise 2 – Is it true that “if at least some good scientific theories could proven to be false, then not all good arguments are logically sound?” Yes. Scientists give good arguments in favor of good scientific theories. If all good scientific theories are proven to be true by sound arguments, then they can’t be proven to be false. Sound arguments would guarantee the theories are true because the premises would be true and the arguments for the theories would be valid—valid arguments can’t have true premises and false conclusions at the same time.

Given these two premises, the conclusion must be true (that not all good arguments are logically sound). Why? Because this argument uses a valid logical form. The logical form is “a. If a, then b. Therefore, b.” This valid logical form is well-known to be valid and is called “modus ponens.”

Derek Parfit: Does Anything Matter?

I must admit that I have Derek Parfit‘s long-awaited book On What Matters sitting on my nightstand at the moment. I’m aided in my procrastination by its daunting length—over 1400 pages in two volumes.

Most of us might come to the same conclusion as Parfit on the question of what matters—”we rich people give up some of our luxuries, ceasing to overheat the Earth’s atmosphere, and taking care of this planet in other ways so that it continues to support intelligent life.”

What we gain from reading Parfait, however, according to the article below, “is the possibility of defending these and other moral claims as objective truths.”

If his new book is half as mind-blowing and lucid as Reasons and Persons, I’ll enjoy the moment I stop balking at its sheer intellectual size and immerse myself.

Many people assume that rationality is always instrumental: reason can tell us only how to get what we want, but our basic wants and desires are beyond the scope of reasoning. Not so, Parfit argues. Just as we can grasp the truth that 1 + 1 = 2, so we can see that I have a reason to avoid suffering agony at some future time, regardless of whether I now care about, or have desires about, whether I will suffer agony at that time. We can also have reasons (though not always conclusive reasons) to prevent others from suffering agony. Such self-evident normative truths provide the basis for Parfit’s defense of objectivity in ethics.

One major argument against objectivism in ethics is that people disagree deeply about right and wrong, and this disagreement extends to philosophers who cannot be accused of being ignorant or confused. If great thinkers like Immanuel Kant and Jeremy Bentham disagree about what we ought to do, can there really be an objectively true answer to that question?

Parfit’s response to this line of argument leads him to make a claim that is perhaps even bolder than his defense of objectivism in ethics. He considers three leading theories about what we ought to do – one deriving from Kant, one from the social-contract tradition of Hobbes, Locke, Rousseau, and the contemporary philosophers John Rawls and T.M. Scanlon, and one from Bentham’s utilitarianism – and argues that the Kantian and social-contract theories must be revised in order to be defensible.

Then he argues that these revised theories coincide with a particular form of consequentialism, which is a theory in the same broad family as utilitarianism. If Parfit is right, there is much less disagreement between apparently conflicting moral theories than we all thought. The defenders of each of these theories are, in Parfit’s vivid phrase, “climbing the same mountain on different sides.”

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You can buy the two-volume set or get the core of his argument in the first 400 pages of volume one. Parfit is also the author of the mind-blowing Reasons and Persons.