Logically Illogical

Faulty logic is one reason why groups make defective decisions. In long discussions, spanning many meetings, email messages and other postings, a chain of logic emerges. Usually, the chain is valid and coherent, but when the conversation becomes complex, when the stakes are high, or when time is short, a group can make logical errors. Here's a small collection.

The fallacy fallacy

If the argument used to reach our conclusions is later found to be flawed, we sometimes believe that the conclusion produced by that argument must also be false.

Not so. That we reached a particular conclusion by faulty logic doesn't mean that the conclusion itself is false. The conclusion might be true, or it might be false.

Sand castle fallacy

If the argument is founded on premises that later prove to be false, or partly false, we sometimes believe that the conclusion produced by that argument must also be false.

Not so. That we reached a particular conclusion based on faulty premises doesn't mean that the conclusion is false. We might have built a castle on sand, but it might still be a castle. If we can find a better foundation for that castle, it might yet prove durable.

Affirming a disjunct

If we know that A or B is true, and it turns out that A is true, we sometimes conclude that B must be false.

The fallacy here arises in instances when A and B are both true. In informal conversation, we often use "or" in the exclusive sense: either A or B, but not both. But in many situations, "or" actually is valid in the inclusive sense: A or B or possibly both A and B.

Affirming the consequent

When a conversation becomes
complex, when the stakes
are high, or when time
is short, a group can
make logical errors

In this error, sometimes called the converse error, we conclude incorrectly that a premise must be true if the conclusion is true. That is, when we know that P implies Q, and we know that Q holds, we wrongly conclude that P must also be true.

The problem here is that the converse of a true statement isn't necessarily true. The contrapositive is true, though: if not Q then not P.

Denying the antecedent

This formal fallacy, sometimes also called the inverse error, is committed when we know that if P, then Q. If we later find that P is false, we then sometimes conclude erroneously that Q is false.

All we can say for sure is that Q might be false when P is false; Q might also be true.

Keeping these errors and their names straight can be difficult, but learning to recognize and avoid them is certainly easier. There is a trap, though. Once you notice that a group has committed one of these errors, remember that it's often possible that their conclusion is correct. To forget that possibility is to commit the fallacy fallacy.  Top    Next Issue

Are you fed up with tense, explosive meetings? Are you or a colleague the target of a bully? Destructive conflict can ruin organizations. But if we believe that all conflict is destructive, and that we can somehow eliminate conflict, or that conflict is an enemy of productivity, then we're in conflict with Conflict itself. Read 101 Tips for Managing Conflict to learn how to make peace with conflict and make it an organizational asset. Order Now!

Your comments are welcome

About Point Lookout

Thank you for reading this article. I hope you enjoyed it and found it useful, and that you'll consider recommending it to a friend.

Point Lookout is a free weekly email newsletter. Browse the archive of past issues. Subscribe for free.

Support Point Lookout by joining the Friends of Point Lookout, as an individual or as an organization.

Do you face a complex interpersonal situation? Send it in, anonymously if you like, and I'll give you my two cents.

Related articles

More articles on Personal, Team, and Organizational Effectiveness:

When Your Boss Is a Micromanager

If your boss is a micromanager, your life can be a seemingly endless misery of humiliation and frustration. Changing your boss is one possible solution, but it's unlikely to succeed. What you can do is change the way you experience the micromanagement.

Give It Your All

If you have the time and resources to read this, you probably have a pretty good situation, or you have what it takes to be looking for one. In many ways, you're one of the fortunate few. Are you making the most of the wonderful things you have? Are you giving it your all?

Give Me the Bad News First

I have good news and bad news. The bad news is that if you wait long enough, there will be some bad news. The good news is that the good news helps us deal with the bad news. And it helps a lot more if we get the bad news first.

Teamwork Myths: Formation

Much of the conventional wisdom about teams is in the form of over-generalized rules of thumb, or myths. In this first part of our survey of teamwork myths, we examine two myths about forming teams.

Creating Toxic Conflict: I

Many managers seem to operate as if their primary goal is to create toxic conflict among their subordinates. Here's a collection of methods for sowing toxic conflict that can help bad managers become worse managers.

See also Personal, Team, and Organizational Effectiveness, Conflict Management and Critical Thinking at Work for more related articles.

Forthcoming issues of Point Lookout

Coming February 3: Cost Concerns: Scale

When we consider the costs of problem solutions too early in the problem-solving process, the results of comparing alternatives might be unreliable. Deferring cost concerns until we fully understand the problem can yield more options and better decisions. Available here and by RSS on February 3.

And on February 10: Remote Hires: Communications

When knowledge-oriented organizations hire remote workers, success is limited by the communications facilities they provide. Remote hires need phones, computers, email, text, video, calendars, and more. Communications infrastructure drives productivity. Available here and by RSS on February 10.

Coaching services

I offer email and telephone coaching at both corporate and individual rates. Contact Rick for details at rbrenhZLYrRMtUnyjppRsner@ChacotqZAFalhYTBMgJWoCanyon.com or (650) 787-6475, or toll-free in the continental US at (866) 378-5470.

Get the ebook!

Past issues of Point Lookout are available in six ebooks:

• Get 2001-2 in Geese Don't Land on Twigs (PDF, )
• Get 2003-4 in Why Dogs Wag (PDF, )
• Get 2005-6 in Loopy Things We Do (PDF, )
• Get 2007-8 in Things We Believe That Maybe Aren't So True (PDF, )
• Get 2009-10 in The Questions Not Asked (PDF, )
• Get all of the first twelve years (2001-2012) in The Collected Issues of Point Lookout (PDF, )

Are you a writer, editor or publisher on deadline? Are you looking for an article that will get people talking and get compliments flying your way? You can have 500-1000 words in your inbox in one hour. License any article from this Web site. More info

Public seminars

The Power Affect: How We Express Our Personal Power

Many people who possess real organizational power have a characteristic demeanor. It's the way they project their presence. I call this the power affect. Some people — call them power pretenders — adopt the power affect well before they attain significant organizational power. Unfortunately for their colleagues, and for their organizations, power pretenders can attain organizational power out of proportion to their merit or abilities. Understanding the power affect is therefore important for anyone who aims to attain power, or anyone who works with power pretenders. Read more about this program.

• A recording of a program presented June 29, 2017, Monthly Webinar, sponsored by Technobility Webinar Series. PMI members can earn 1.0 Category 'A' PDU by viewing this program. View this program now.
   
• A recording of a program presented June 29, 2017, Monthly Webinar, sponsored by Technobility Webinar Series. PMI members can earn 1.0 Category 'A' PDU by viewing this program. View this program now.
   

Bullet Points: Mastery or Madness?

Decision-makers in modern organizations commonly demand briefings in the form of bullet points or a series of series of bullet points. But this form of presentation has limited value for complex decisions. We need something more. We actually need to think. Briefers who combine the bullet-point format with a variety of persuasion techniques can mislead decision-makers, guiding them into making poor decisions. Read more about this program.

• A recording of a program presented June 24, 2020, Monthly Webinar, sponsored by Technobility Webinar Series. PMI members can earn 1.0 Category 'A' PDU by viewing this program. View this program now.
   
• A recording of a program presented June 24, 2020, Monthly Webinar, sponsored by Technobility Webinar Series. PMI members can earn 1.0 Category 'A' PDU by viewing this program. View this program now.