April 2012 is going down in my project management record book as the busiest and most intense work weeks for as long as I can remember — and that is a good thing. To accommodate my over-flowing task schedule, I have asked a fellow PM and writer, Barbara Brown, to create this week’s post.
Thank you, Bruce. It is a pleasure to have the opportunity to share on a topic I have been thinking about recently – logical fallacies. I know that sounds arcane and academic. However, identifying fallacious arguments can sometimes help you win a contentious point in a business discussion. Or, at least, construct a masterful putdown when you are talking back to a radio or TV commentator.
N. B.: Keep in mind that few people appreciate having the logic of their conclusions questioned. Therefore, in many situations, it is best to keep your insights to yourself and use this knowledge only to improve the validity of your own arguments.
What is a logic fallacy?
Logic is about drawing justifiable conclusions from premises or data. The prototypical example of deductive logical reasoning is: All men are mortal (premise1), Socrates is a man (premise 2); therefore Socrates is mortal (conclusion). In more normal conversation, however, the conclusions are often not clearly reachable from considering only the premises because — wait for it — the speaker engages in the use of logic fallacies. Here is an example:
(P1) Barack Obama was elected president in 2008;
(P2) The economy began falling apart in 2008; therefore
(C) Barack Obama caused the poor economic conditions.
This example shows a relatively common logical fallacy, especially in an election year, called: post hoc ergo propter hoc or just post hoc for short. This argument is fallacious because it assumes causality based solely on chronology.
Other Frequently Encountered Logic Fallacies
“Straw Man” The person presenting an argument with a “straw man” wants to appear as if he or she has considered the opposition’s arguments and can refute them. They accomplish this feat by selecting an exaggerated example supposedly from the other side, and then proceed to disprove the example. Sounds reasonable, doesn’t it. However, the trick to a “straw man” debate is that the person chooses a weak argument for the opposing side or misrepresents their position. Then, they ask you to conclude, in essence, if one of the opponent’s arguments can be so easily shown false, then all of their arguments are wrong, which is why this type of logical fallacy is also called, a fallacy of extension. Example:
Agile programming teams have no manager to lead them
Teams without a sense of direction or purpose are destined to fail
Therefore, developing software using agile methods will fail.
“False Dilemma” This logic fallacy uses an argument that assumes there are only two decision options, when in reality there are many options.
We have to choose between Microsoft Project and Primavera for our project management software.
“Slippery Slope” In this type of logical fallacy, if one accepts a slightly disagreeable action one must also accept that this will lead to increasingly bad events.
If Robert is not punished for failing to turn in his status report, then no one will feel compelled to report project status. Without status information, management will make poor decisions and projects will fail. If projects fail, the company will lose market share. If we lose market share, we will go bankrupted and we will all be without a job. Therefore, Robert must be fired.
“Complex Question” joins two premises (one, usually, unstated) as if they were one. This technique is often called, “asking a loaded question”. The logical fallacy is in the assumption that the two premises are linked. The complex question fallacy is committed when a question rests on an unproven assumption.
How do you expect to be an effective manager when you cannot get to work on time?
I know that dissecting discussions for their logical fallacies is not everyone’s cup of tea. However, I confess that sometimes on the ride home from work through stop-and-go traffic, I have felt better about losing a contentious point when I can find the fallacy in my antagonist’s argument.
If you want to have some more fun with logic, you might enjoy listening to the LSAT Logic in Everyday Life podcasts.