In her book, Critical Thinking: An Appeal To Reason, Peg Tittle has an interesting and useful way of organizing 15 logical fallacies. Simply put, they’re all irrelevant to the assessment of whether an argument is true or not. Using Tittle’s guidelines, we can quickly sort out what we need to pay attention to and what we can safely ignore.
Though these fallacies are irrelevant to truth, they are very relevant to persuasion. Critical thinking is about discovering the truth; it’s about the present and the past. Persuasion is about the future, where truth has yet to be established. Critical thinking helps us decide what we can be certain of. Persuasion helps us make good choices when we’re uncertain. Critical thinking is about truth; persuasion is about choice. What’s poison to one is often catnip to the other.
With that thought in mind, let’s take a look at Tittle’s 15 irrelevant fallacies. If someone tosses one of these at you in a debate, your response is simple: “That’s irrelevant.”
Chances are that you’ve used some of these fallacies in a debate or argument. Indeed, you may have convinced someone to choose X rather than Y using them. Though these fallacies may be persuasive, it’s useful to remember that they have nothing to do with truth.
This fall, in addition to my regular academic courses, I’ll teach three one-day seminars designed for managers and executives.
These seminars draw on my academic courses and are repackaged for professionals who want to think more clearly and persuade more effectively. They also provide continuing education credits under the auspices of the University of Denver’s Center for Professional Development.
If you’re guiding your organization into an uncertain future, you’ll find them helpful. Here are the dates and titles along with links to the registration pages.
I hope to see you in one or more of these seminars. If you’re not in the Denver area, I can also take these on the road. Just let me know of your interest.
People often ask me why they should take a class in critical thinking. Their typical refrain is, “I already know how to think.” I find that the best answer is a story about the mistakes we often make.
So I offer up the following example, drawn from recent news, about very smart people who missed a critical clue because they were not thinking critically.
The story is about the conventional wisdom surrounding Alzheimer’s. We’ve known for years that people who have Alzheimer’s also have higher than normal deposits of beta amyloid plaques in their brains. These plaques build up over time and interfere with memory and cognitive processes.
The conventional wisdom holds that beta amyloid plaques are an aberration. The brain has essentially gone haywire and starts to attack itself. It’s a mistake. A key research question has been: how do we prevent this mistake from happening? It’s a difficult question to answer because we have no idea what triggered the mistake.
But recent research, led by Rudolph Tanzi and Robert Moir, considers the opposite question. What if the buildup of beta amyloid plaques is not a mistake? What if it serves some useful purpose? (Click here and here for background articles).
Pursuing this line of reasoning, Tanzi and Moir discovered the beta amyloid is actually an antimicrobial substance. It has a beneficial purpose: to attack bacteria and viruses and smother them. It’s not a mistake; it’s a defense mechanism.
Other Alzheimer’s researchers have described themselves as “gobsmacked” and “surprised” by the discovery. One said, “I never thought about it as a possibility.”
A student of critical thinking might ask, Why didn’t they think about this sooner? A key tenet of critical thinking is that one should always ask the opposite question. If conventional wisdom holds that X is true, a critical thinker would automatically ask, Is it possible that the opposite of X is true in some way?
Asking the opposite question is a simple way to identify, clarify, and check our assumptions. When the conventional wisdom is correct, it leads to a dead end. But, occasionally, asking the opposite question can lead to a Nobel Prize. Consider the case of Barry Marshall.
A doctor in Perth, Australia, Marshall was concerned about his patients’ stomach ulcers. Conventional wisdom held that bacteria couldn’t possibly live in the gastric juices of the human gut. So bacteria couldn’t possibly cause ulcers. More likely, stress and anxiety were the culprits. But Marshall asked the opposite question and discovered the bacteria now known a H. Pylori. Stress doesn’t cause ulcer, bacteria do. For asking the opposite question — and answering it — Marshall won the Nobel Prize in Medicine in 2005.
The discipline of critical thinking gives us a structure and method – almost a checklist – for how to think through complex problems. We should always ask the opposite question. We should be aware of common fallacies and cognitive biases. We should understand the basics of logic and argumentation. We should ask simple, blunt questions. We should check our egos at the door. If we do all this – and more – we tilt the odds in our favor. We prepare our minds systematically and open them to new possibilities – perhaps even the possibility of curing Alzheimer’s. That’s a good reason to study critical thinking.
It’s hard to think critically when you don’t know what you’re missing. As we think about improving our thinking, we need to account for two things that are so subtle that we don’t fully recognize them:
Because of assumptions and filters, we often talk past each other. The world is a confusing place and becomes even more confusing when our perception of what’s “out there” is unique. How can we overcome these effects? We need to consider two sets of questions:
The more we study assumptions and filters, the more attuned we become to their prevalence. When we make a decision, we’ll remember to inquire abut ourselves before we inquire about the world around us. That will lead us to better decisions.
In my critical thinking class, we begin by studying 17 cognitive biases that are drawn from Peter Facione’s excellent textbook, Think Critically. (I’ve also summarized these here, here, here, and here). I like the way Facione organizes and describes the major biases. His work is very teachable. And 17 is a manageable number of biases to teach and discuss.
While the 17 biases provide a good introduction to the topic, there are more biases that we need to be aware of. For instance, there’s the survivorship bias. Then there’s swimmer’s body fallacy. And the Ikea effect. And the self-herding bias. And don’t forget the fallacy fallacy. How many biases are there in total? Well, it depends on who’s counting and how many hairs we’d like to split. One author says there are 25. Another suggests that there are 53. Whatever the precise number, there are enough cognitive biases that leading consulting firms like McKinsey now have “debiasing” practices to help their clients make better decisions.
The ultimate list of cognitive biases probably comes from Wikipedia, which identifies 104 biases. (Click here and here). Frankly, I think Wikipedia is splitting hairs. But I do like the way Wikipedia organizes the various biases into four major categories. The categorization helps us think about how biases arise and, therefore, how we might overcome them. The four categories are:
1) Biases that arise from too much information – examples include: We notice things already primed in memory. We notice (and remember) vivid or bizarre events. We notice (and attend to) details that confirm our beliefs.
2) Not enough meaning – examples include: We fill in blanks from stereotypes and prior experience. We conclude that things that we’re familiar with are better in some regard than things we’re not familiar with. We calculate risk based on what we remember (and we remember vivid or bizarre events).
3) How we remember – examples include: We reduce events (and memories of events) to the key elements. We edit memories after the fact. We conflate memories that happened at similar times even though in different places or that happened in the same place even though at different times, … or with the same people, etc.
4) The need to act fast – examples include: We favor simple options with more complete information over more complex options with less complete information. Inertia – if we’ve started something, we continue to pursue it rather than changing to a different option.
It’s hard to keep 17 things in mind, much less 104. But we can keep four things in mind. I find that these four categories are useful because, as I make decisions, I can ask myself simple questions, like: “Hmmm, am I suffering from too much information or not enough meaning?” I can remember these categories and carry them with me. The result is often a better decision.