Logical Fallacies

Early on in the exploration of reasonableness we made a point of acknowledging basic human fallibility. Inquiry is not a linear path from absolute truth to absolute truth. Inquiry is a more typically a meandering path with frequent back tracking as we learn from or mistakes. Our conclusions, even when they support a healthy degree of confidence, remain always provisional. New evidence or argument may reveal previously unrecognized mistakes. Of course, learning from our mistakes does require that being able to recognize them. Many of the mistakes in reasoning we humans are prone to are well known. These are fallacies. A fallacy is just a mistake in reasoning. Assuming we’ve developed a decent understanding of what good reasoning looks like over the prior chapters, we should now be in a position to examine some common fallacies and understand why they are mistakes.

I will only discuss a choice selection of fallacies here. A full course in critical thinking would introduce you to many more and include lots of practice at identifying them, first in text book exercises, then “in the wild.”

• Ad hominem: This fallacy is known is Latin for “against the person.”As the name suggests, ad hominem consists of attacking the proponent of a position rather than critically evaluating the reasons offered for the proponent’s position. The reason ad hominem is a fallacy is that the attack on an individual is simply not relevant to the quality of the reasoning offered by that person. Attacking the person who offers an argument has nothing to do whether or not the premises of the argument are true or whether they support the conclusion. Ad hominem amounts to a way of changing the subject from whatever was at issue to potential flaws in the character or behavior of the person who was trying to reason about that issue. Part of what makes Ad hominem so effective is that people are generally quick to defend their honor.

Ad hominem is a particularly rampant and destructive fallacy in our society. I quickly turns the cooperative social project of inquiry through conversation into polarized verbal combat. This fallacy makes reasonable dialogue impossible while it diverts attention from interesting issues that often could be fruitfully investigated.

Here’s an example of ad hominem: A car salesman argues for the quality of an automobile and the potential buyer discounts the argument with the thought that the person is just trying to earn a commission. We can imagine a situation where the salesperson is just trying to earn a commission and yet he is also making good arguments. Consider a salesman who doesn’t really care so much about his customers and mainly just wants to make lots of money. However, this salesperson is not very good at lying and manipulating people and decides that the best way to earn good commissions is to research his product carefully and then to only accept a sales position with the business that sells the very best. He then sincerely delivers good arguments for the quality of his product, makes lots of money, and dresses well. The customer who rejects his reasons for buying the car he sells on the ad hominim grounds that he is just trying to earn a commission misses an opportunity to buy the best. The moral of the story is just that the salesperson’s motive is logically independent of the quality of his argument. The quality of an argument or an idea doesn’t depend on who is offering it or what their motivation is.

• False Dichotomy: A dichotomy is an either/or choice where this is no third or fourth option. We’ve seen an example of a dichotomy in the contrast between the claim that there is intelligent life on other planets and the claim that there is no intelligent life on other planets. If one option is false then the other is true. There is no third or fourth possibility. On the other hand, when you go to a restaurant and you are trying to decide between the Impossible Burger or the Caesar Salad, you are probably not facing a dichotomy. You also have the option of having the salmon, or perhaps the fajita. The fallacy of false dichotomy is committed when we are presented with just two options as if these were the only possibilities when in fact there may be a third, fourth or more other possibilities.

So, here is a famous example of the false dichotomy fallacy. Shortly after 911, George W. Bush proclaimed, “You are either with us or you are with the terrorists.” Not long after that Bush launched a war against Iraq in the name of fighting terrorism. Some American’s protested the invasion of Iraq, arguing that we did not have good reason to feel threatened by that country and that an unjust war would inspire more terrorism than it prevented. Critics of the war in Iraq were as opposed to terrorism as the rest of America, they simply doubted that the Bush administration’s invasion of Iraq would be an effective way to combat terrorism. As it turns out, Iraq did not have the weapons of mass destruction it was alleged to have and it was not at the time a sponsor of terrorism (though many members of Iraq’s disbanded military went on to join terrorist organizations after we invaded Iraq). The long war in Iraq took an enormous toll on human life and well-being both to US and international service personnel but mostly to Iraqi citizens. The war badly damaged US standing on the international stage and it inspired a great deal of terrorism, mostly in Iraq and then Syria, often targeting US military personnel as well as civilians. Critics of the war here in the US were neither with the Bush administration nor with the terrorists. They shared the Bush administration’s goal of ending terrorism but opposed it’s strategy for achieving this goal.

• Straw Man: When soldiers fought with bayonets on their rifles, they would train by attacking straw men. Straw men are fairly easy to stab with a bayonet since they don’t run away or fight back. But then stabbing a straw man is no victory over an actual opponent. The fallacy of straw man is committed when someone criticizes an easy to attack distortion of an argument or idea rather than the actual view. Like many fallacies, this one can be committed deliberately or inadvertently. In our highly polarized social media environment, it is not uncommon for a disingenuous manipulator to deliberately broadcast a straw man attack (or some other fallacy) all the while knowing that his audience, lacking well-developed critical thinking skills, will fall for the manipulation and go on to propagate the bad argument unwittingly. This is often how propaganda works.

You may have heard a commonly propagated straw man attack committed against efforts to address climate change. Critics will often charge that people concerned about climate change are really just socialists looking to take our freedom away. There’s a lot going on here and its worth pointing out the fallacies are gregarious. It is quite possible to commit more than one at a time. So, you might also notice an element of ad hominem in this example where reasons for taking climate seriously get ignored in favor of attacking the people trying to take climate seriously. This sheds some light on the old quip that lies travel half way around the world before the truth gets its shoes on. It takes lots more work to diagnose and filter out fallacies than it does to commit and propagate them. But aside from the ad hominem attack, this notion that people who want to see action on climate change are just big government lovers includes a straw man fallacy. It is easy and appealing to attack the socialist idea of government taking over the economy. It is not so easy to attack the idea that we have a serious problem in climate change and effective government action will be required to address it. Climate advocates are not arguing for socialism, a complete government take over of the economy. They are arguing for government and business to work together to move us rapidly towards a sustainable economy, one that is based on renewable energy instead of fossil fuels, sustainable agriculture instead of deforestation, etc. Who owns and operates the industries of the future is simply not what is at issue, though many climate activists will be quick to point out the entrepreneurial opportunities in shifting to a more sustainable economy. In light of the existential risk we face in climate change, the policy measures called for are much harder to argue against than the straw man of widely despised socialism.

• Hasty generalization:  The human brain has evolved to recognize patterns and project from these to unobserved instances. We instinctively expect things to continue to happen in accordance with the patterns we have observed. When we generalize from genuinely reliable patterns, our inferences can be inductively strong. But assuring the strength of our inductive generalizations requires that we generalize from ample evidence that is actually reflective of larger patterns in the world. In everyday life, we are highly prone to short circuiting this process and drawing generalizations too quickly from too little evidence, or evidence that is biased or distorted in some manner. When we do so, we generalize hastily and commit this fallacy.

Our fears and anxieties are often complicit in our hasty generalizations. When we hear a rustling in the bushes that sounds like it could be a mountain lion, the price of not jumping to this conclusion and being wrong (failing to infer that there is a mountain lion when there is one) is much higher than the price of making the inference and misfiring (inferring that there is a mountain lion when there is none). Evolution favors hastily inductive inference, much more so than generalizing methodically and scientifically. Where our fears are rational, this is all well and good. But fear is often not rational, and worse, our fears are easily manipulated. Hasty generalization on the basis of irrational or manipulated fear is the foundation of some of the worst injustices people perpetrate. Racial prejudice is a prime example.

The German Historical Museum in Berlin curates a vast collection of antisemitic propaganda tracing German history leading up to the Holocaust. An examination of this history quickly reveals that prejudice is often founded on hasty generalizations. Further, these hasty generalizations are largely built on manufactured evidence. The propaganda that stoked generalize antisemitism was not typically based on fact. Fear is a powerful motivator both when it is credible and when it is not. Our own societies treatment of Black Americans provides many further troubling examples of the racial injustice based on hasty generalizations from biased or even fabricated representations. I’ll discuss just one example here, but in the context of another inductive fallacy.

• Spurious Correlation: When we find a significant correlation between one condition and another, it is tempting to assume this indicates that one condition causes the other. Indeed, often it does. The high correlation between flipping the light switch and the room lighting up is explained by the former action causing the later condition. But this correlation between one condition and another doesn’t aways work this way. It can also, for instance, be that both conditions have a common cause. So, night routinely follows day, but day does not cause night. The correlation we find in night following day is caused by the rotation of the planet as it orbits the sun.

Official crime rates among Black Americans are higher than they are among white Americans. The statistics here need to be understood in the context of an assortment racial biases in the criminal justice system. This is not just a matter of individual police officers being racially biased, though some are. There are also a number of systemic factors involved. Poor neighborhoods are more heavily policed and these tend to be more racially diverse. The crack cocaine epidemic that plagued Black communities was aggressively prosecuted an sent many Black people to prison. The current wave of opioid addiction that more often afflicts white communities is treated with more compassion than prosecution. So, there is a good deal of institutional racial bias built into the official crime statistics. But even if we bracket these injustices, the correlation between crime and race in official statistics is spurious. It does not track a causal connection between race and crime.

The gap in official crime rates between Black Americans and white Americans leads a significant number of people to the conclusion that Black people are just more criminally prone, as if race alone could explain this. But this racist conclusion is not well supported. The gap in crime rates closely mirrors the gap in unemployment rates between Black Americans and whites. Both official crime rates and official unemployment rates are higher among Blacks by similar factors. This suggests a causal explanation for higher crime rates among Black Americans that makes a good deal of sense and doesn’t attribute innate criminality to Black Americans as racists would have us believe. People generally turn to crime only when they are deprived of decent opportunities in life. Regardless of race, people with good jobs and some prospects for a decent life have lots to lose and won’t be very prone to risk it all on criminal activity.

Correlations call for explanations. The inductive pattern of argument involved here is inference to the best explanation. So, let’s recall how the surprise principle discussed in the last chapter works. The explanation that makes the correlation we want to explain least surprising is the one that explains best and is thereby inductively confirmed. The idea that race somehow explains criminality is rather mysterious. There have been many racially motivated attempts to substantiate this idea and none have panned out. But higher crime rates among people who have been denied opportunities in life is not at all surprising. Inference to the best explanation strongly favors the idea that unemployment is a significant causal factor in crime over the idea that race somehow explains crime. The correlation between crime and race is spurious, not causal.

We should pause here to note that racism has a good deal to do with the gap in employment and economic opportunity between Black and white Americans. Higher unemployment among Black people is partly the result of racist attitudes like seeing Black people criminally prone. So, Black people in America face a tragically vicious feedback loop where racist attitudes combined with institutionalized racism serve to generate data about crime rates which in turn fallaciously reinforce racist attitudes which in turn deprives Black people of economic opportunity which then leads to higher crime rates and so on.

Of course, there are other dynamics at play and it is well worth inquiring into these. I’d recommend any one of several courses in Sociology or Cultural and Ethnic studies for developing a better understanding of the tangled web of racial injustice afflicting our society. Bring your critical thinking skills and you will gain a better appreciation for how shoddy fallacious arguments fuel inequality and injustice and betray the values we aspire to in a free and open society.

It is possible that discussion of race here will make a few readers uncomfortable. So, this would be a good place to point out how being reasonable is not always comfortable. I’d refer us back to our earlier discussion of intellectual courage.

There are many more fallacies worth getting familiar with. I’ll leave you to explore these on your own. The The Fallacy Files is a good place to start. I’ll wrap up here with a brief discussion of confirmation bias. Confirmation bias isn’t really a fallacy because it isn’t a specific kind of mistake in reasoning. Confirmation bias is the intellectual bad habit of endorsing just the evidence and argument that seems to support the view you already hold. We might think of confirmation bias as a meta-fallacy. It’s the bad habit of trafficking in fallacious arguments for conclusions we like. Any fallacy can be involved in confirmation bias.

Confirmation bias is about what we should expect to find among people who lack strong critical thinking skills. People who don’t know how to evaluate arguments have little else to go on except to prefer arguments that seem to confirm opinions they hold. We all have good reason to avoid confirmation bias because it tends to undermine our credibility. Even if your view is well supported by good reasons, your presentation of it will be far less persuasive when you throw in a few shoddy reasons as well. Your audience is likely to feel manipulated and to lose faith in your intellectual integrity. The only way to avoid confirmation bias is through cultivating critical thinking skill of your own by learning how to evaluate arguments and identify fallacies.