Quick Question: What's the formal name of this fallacy?

Use this philosophy forum to discuss and debate general philosophy topics that don't fit into one of the other categories.

This forum is NOT for factual, informational or scientific questions about philosophy (e.g. "What year was Socrates born?"). Those kind of questions can be asked in the off-topic section.
Post Reply
User avatar
labarith
New Trial Member
Posts: 5
Joined: June 13th, 2022, 7:09 pm

Quick Question: What's the formal name of this fallacy?

Post by labarith »

I came across a fallacy in a recent article but for the life of me I can't think of the formal term for the fallacy. Any help would be appreciated.

I'll try to describe it as best I can. The author begins with a case and says a disjunction is (a v b) is true of the case, then constructs a separate case in which the first option a is not an option, thereby concluding b must be true of both cases.

Here's an example (other than the one the author uses):

Case 1: Jane is wearing a blue dress.

In this case, the following proposition p is true: (Jane is wearing a dress OR Brown is in Barcelona)

Case 2: Jane is not wearing a dress.

Therefore, in case 2, Brown is in Barcelona.
User avatar
Pattern-chaser
Premium Member
Posts: 8265
Joined: September 22nd, 2019, 5:17 am
Favorite Philosopher: Cratylus
Location: England

Re: Quick Question: What's the formal name of this fallacy?

Post by Pattern-chaser »

labarith wrote: June 13th, 2022, 7:19 pm In this case, the following proposition p is true: (Jane is wearing a dress OR Brown is in Barcelona)

Case 2: Jane is not wearing a dress.

Therefore, in case 2, Brown is in Barcelona.
This case, as described, appears valid. If the premise is correct (and it probably wouldn't be, in practice), and Jane is not wearing a dress, then Brown is in Barcelona. I see no fallacy here. Perhaps a better example might offer better understanding?
Pattern-chaser

"Who cares, wins"
User avatar
labarith
New Trial Member
Posts: 5
Joined: June 13th, 2022, 7:09 pm

Re: Quick Question: What's the formal name of this fallacy?

Post by labarith »

I'm sorry for any confusion.

Proposition p is true of case 1 (because Jane *is* wearing a dress), but there is no reason to think it's true for case 2.
(These are both fictional cases, and the cases denote all we know about those worlds.)
User avatar
Thomyum2
Posts: 366
Joined: June 10th, 2019, 4:21 pm
Favorite Philosopher: Robert Pirsig + William James

Re: Quick Question: What's the formal name of this fallacy?

Post by Thomyum2 »

labarith wrote: June 13th, 2022, 7:19 pm I came across a fallacy in a recent article but for the life of me I can't think of the formal term for the fallacy. Any help would be appreciated.

I'll try to describe it as best I can. The author begins with a case and says a disjunction is (a v b) is true of the case, then constructs a separate case in which the first option a is not an option, thereby concluding b must be true of both cases.

Here's an example (other than the one the author uses):

Case 1: Jane is wearing a blue dress.

In this case, the following proposition p is true: (Jane is wearing a dress OR Brown is in Barcelona)

Case 2: Jane is not wearing a dress.

Therefore, in case 2, Brown is in Barcelona.
I'm not sure there is a name specifically for this particular type of fallacy, but it would be considered a formal fallacy and a type of non sequitur. It's sort of a variation on the fallacy of denying the antecedent, but I think it's probably better classified as a fallacy of an affirmative conclusion from a negative premise.
“We have two ears and one mouth so that we can listen twice as much as we speak.”
— Epictetus
GE Morton
Posts: 4696
Joined: February 1st, 2017, 1:06 am

Re: Quick Question: What's the formal name of this fallacy?

Post by GE Morton »

labarith wrote: June 13th, 2022, 7:19 pm I came across a fallacy in a recent article but for the life of me I can't think of the formal term for the fallacy. Any help would be appreciated.

I'll try to describe it as best I can. The author begins with a case and says a disjunction is (a v b) is true of the case, then constructs a separate case in which the first option a is not an option, thereby concluding b must be true of both cases.

Here's an example (other than the one the author uses):

Case 1: Jane is wearing a blue dress.

In this case, the following proposition p is true: (Jane is wearing a dress OR Brown is in Barcelona)

Case 2: Jane is not wearing a dress.

Therefore, in case 2, Brown is in Barcelona.
You haven't put those in the form of a proper argument. Is there one argument there, or two? If it is all one argument, then it is self-contradictory (Jane both is and is not wearing a blue dress). If "Case 2" is a separate argument, then it is simply a non-sequitur, since there is no premise involving Brown.
User avatar
labarith
New Trial Member
Posts: 5
Joined: June 13th, 2022, 7:09 pm

Re: Quick Question: What's the formal name of this fallacy?

Post by labarith »

GE Morton wrote: June 14th, 2022, 9:29 pm You haven't put those in the form of a proper argument. Is there one argument there, or two? If it is all one argument, then it is self-contradictory (Jane both is and is not wearing a blue dress). If "Case 2" is a separate argument, then it is simply a non-sequitur, since there is no premise involving Brown.
The cases are distinct.

Of case 1, the author says either (a v b) is true. As it so happens, it is true because a is true.

However, the author wants to argue b to be true, not a. So they construct case 2, which is exactly like case 1, except a is not true. The author, then, concludes "Well, (a v b) was true in case 1, a is not an option in case 2, so b must be true in case 2."

I've never come across a mistake like this and wondered if there was any precedent or examples I could call out to succinctly explain the fallacy.

In any case, thanks to everyone who replied.
GE Morton
Posts: 4696
Joined: February 1st, 2017, 1:06 am

Re: Quick Question: What's the formal name of this fallacy?

Post by GE Morton »

labarith wrote: June 14th, 2022, 10:14 pm
GE Morton wrote: June 14th, 2022, 9:29 pm You haven't put those in the form of a proper argument. Is there one argument there, or two? If it is all one argument, then it is self-contradictory (Jane both is and is not wearing a blue dress). If "Case 2" is a separate argument, then it is simply a non-sequitur, since there is no premise involving Brown.
The cases are distinct.
The "cases" may be distinct, but what the argument is, is unclear. Only logical fallacies have "formal names," and they only apply to logical arguments.

You need to dispense with the "cases" and re-formulate the question as an argument, with premises and a conclusion.
User avatar
labarith
New Trial Member
Posts: 5
Joined: June 13th, 2022, 7:09 pm

Re: Quick Question: What's the formal name of this fallacy?

Post by labarith »

GE Morton wrote: June 15th, 2022, 12:44 pm
labarith wrote: June 14th, 2022, 10:14 pm
GE Morton wrote: June 14th, 2022, 9:29 pm You haven't put those in the form of a proper argument. Is there one argument there, or two? If it is all one argument, then it is self-contradictory (Jane both is and is not wearing a blue dress). If "Case 2" is a separate argument, then it is simply a non-sequitur, since there is no premise involving Brown.
The cases are distinct.
The "cases" may be distinct, but what the argument is, is unclear. Only logical fallacies have "formal names," and they only apply to logical arguments.

You need to dispense with the "cases" and re-formulate the question as an argument, with premises and a conclusion.
1. In case 1 (a v b)
2. In case 2 ~a.
Conclusion: Therefore b. (of all cases at all times)

Of course, the author wants us to read it as:

1. a v b
2. ~a
C: Therefore, b.

The latter argument, of course, is valid. The former is not, but I'm not sure if there's a formal name for this particular logical error.

I don't *think* this counts as a generalization fallacy, as the problem isn't merely that the author is making a conclusion about the whole based on a conclusion about a single specific case, but rather turns on confusion about the disjunction as well.
User avatar
Pattern-chaser
Premium Member
Posts: 8265
Joined: September 22nd, 2019, 5:17 am
Favorite Philosopher: Cratylus
Location: England

Re: Quick Question: What's the formal name of this fallacy?

Post by Pattern-chaser »

labarith wrote: June 14th, 2022, 12:23 pm Proposition p is true of case 1 (because Jane *is* wearing a dress), but there is no reason to think it's true for case 2.
Yes, there is. You stated that
labarith wrote: June 13th, 2022, 7:19 pm In this case, the following proposition p is true: (Jane is wearing a dress OR Brown is in Barcelona)

Case 2: Jane is not wearing a dress.
Since p is true, then either Jane is wearing a dress or Brown is in Barcelona. We know that Jane isn't wearing a dress, and that p is true, so Brown is in Barcelona.
Pattern-chaser

"Who cares, wins"
GE Morton
Posts: 4696
Joined: February 1st, 2017, 1:06 am

Re: Quick Question: What's the formal name of this fallacy?

Post by GE Morton »

labarith wrote: June 15th, 2022, 1:17 pm
1. In case 1 (a v b)
2. In case 2 ~a.
Conclusion: Therefore b. (of all cases at all times)

Of course, the author wants us to read it as:

1. a v b
2. ~a
C: Therefore, b.

The latter argument, of course, is valid. The former is not, but I'm not sure if there's a formal name for this particular logical error.
The former is the same argument, and is also valid. The "in case" adds nothing to it. And the "all cases at all times" doesn't apply; for that you'd need quantifiers on your variables.
User avatar
labarith
New Trial Member
Posts: 5
Joined: June 13th, 2022, 7:09 pm

Re: Quick Question: What's the formal name of this fallacy?

Post by labarith »

GE Morton wrote: June 15th, 2022, 10:35 pm
labarith wrote: June 15th, 2022, 1:17 pm
1. In case 1 (a v b)
2. In case 2 ~a.
Conclusion: Therefore b. (of all cases at all times)

Of course, the author wants us to read it as:

1. a v b
2. ~a
C: Therefore, b.

The latter argument, of course, is valid. The former is not, but I'm not sure if there's a formal name for this particular logical error.
The former is the same argument, and is also valid. The "in case" adds nothing to it. And the "all cases at all times" doesn't apply; for that you'd need quantifiers on your variables.
Perhaps it's best to back to our original example.

Case 1: Jane is wearing a dress. Brown exists, but we know not where.

If Case 1 is true, then we know proposition:

[*] (p1) Jane is wearing a dress.

Now, as Gettier notes, if we know the truth of some proposition a, we know the disjunction (a v b).
With regards to case 1, we know [Jane is wearing a dress], therefore we know the following disjunctions:
[*] (p2) Either Jane is wearing a dress, or Brown is in Boston.
[*] (p3) Either Jane is wearing a dress, or Brown is in Barcelona.
[*] (p4) Either Jane is wearing a dress, or Brown is in Brest-Litovsk.

Now, consider Case 2:

Case 2: Jane is not wearing a dress. Brown exists, but we know not where.

Of course, for any given proposition ~(p & ~p), so if Jane is wearing a dress in Case 1 and Jane is not wearing a dress in Case 2, then either Jane1 and Jane2 are different people, or Case 1 and Case 2 occur at different times (such that @ during the period of time described in Case 1, Jane is wearing a dress, and during the period of time described in Case 2, Jane is not wearing a dress. In either of these cases, there is no contradiction, but there is also no reason to think that what we say of case 1, proposition (p3) is true of Case 2.

Of course these are hypothetical cases; there is no Jane, no Jane1, no Jane2, no Brown. However, we can still analyze the cases. We can say "If Case 1 were real, then proposition (p1) is true, as is propositions (p2)-(p4).

However, just because (p3) is true of Case 1 is no reason to think (p3) is true of case 2. For example:

Case 3: Adam was born in the year 2000 and attended the Oscars in 2020 and won an Oscar award.

Case 4: Adam was born in the year 1000 and never won any awards.

The following proposition is true of case 3, but not of case 4:

[*] (p5) Adam won an award.

Any confusion regarding the truth or falsity of (p5) comes from ambiguity in which "Adam", which case, the proposition is meant to describe; (p5) is true of Case 3, but then the author - in this case me - specifically changed the scenario described in case 4 so that (p5) would not be true. This is not unusual (For example, consider James Rachels' parallel cases, or David Boonin's Bone Marrow thought experiments).

What is unusual (about the arguments I'm discussing, from a punished author I don't want to besmirch here) is that the author uses a disjunctive proposition about case 1, and treats it as if it is applicable to case 2... despite case 2 being designed to rule out one side of the disjunction (not unlike how my case 4 is designed to rule out the truth of (p5).

Final thought: Perhaps this would have been easier to convey through symbolic logic; is so I apologize for wasting your time.
Post Reply

Return to “General Philosophy”

2023/2024 Philosophy Books of the Month

Entanglement - Quantum and Otherwise

Entanglement - Quantum and Otherwise
by John K Danenbarger
January 2023

Mark Victor Hansen, Relentless: Wisdom Behind the Incomparable Chicken Soup for the Soul

Mark Victor Hansen, Relentless: Wisdom Behind the Incomparable Chicken Soup for the Soul
by Mitzi Perdue
February 2023

Rediscovering the Wisdom of Human Nature: How Civilization Destroys Happiness

Rediscovering the Wisdom of Human Nature: How Civilization Destroys Happiness
by Chet Shupe
March 2023

The Unfakeable Code®

The Unfakeable Code®
by Tony Jeton Selimi
April 2023

The Book: On the Taboo Against Knowing Who You Are

The Book: On the Taboo Against Knowing Who You Are
by Alan Watts
May 2023

Killing Abel

Killing Abel
by Michael Tieman
June 2023

Reconfigurement: Reconfiguring Your Life at Any Stage and Planning Ahead

Reconfigurement: Reconfiguring Your Life at Any Stage and Planning Ahead
by E. Alan Fleischauer
July 2023

First Survivor: The Impossible Childhood Cancer Breakthrough

First Survivor: The Impossible Childhood Cancer Breakthrough
by Mark Unger
August 2023

Predictably Irrational

Predictably Irrational
by Dan Ariely
September 2023

Artwords

Artwords
by Beatriz M. Robles
November 2023

Fireproof Happiness: Extinguishing Anxiety & Igniting Hope

Fireproof Happiness: Extinguishing Anxiety & Igniting Hope
by Dr. Randy Ross
December 2023

Beyond the Golden Door: Seeing the American Dream Through an Immigrant's Eyes

Beyond the Golden Door: Seeing the American Dream Through an Immigrant's Eyes
by Ali Master
February 2024

2022 Philosophy Books of the Month

Emotional Intelligence At Work

Emotional Intelligence At Work
by Richard M Contino & Penelope J Holt
January 2022

Free Will, Do You Have It?

Free Will, Do You Have It?
by Albertus Kral
February 2022

My Enemy in Vietnam

My Enemy in Vietnam
by Billy Springer
March 2022

2X2 on the Ark

2X2 on the Ark
by Mary J Giuffra, PhD
April 2022

The Maestro Monologue

The Maestro Monologue
by Rob White
May 2022

What Makes America Great

What Makes America Great
by Bob Dowell
June 2022

The Truth Is Beyond Belief!

The Truth Is Beyond Belief!
by Jerry Durr
July 2022

Living in Color

Living in Color
by Mike Murphy
August 2022 (tentative)

The Not So Great American Novel

The Not So Great American Novel
by James E Doucette
September 2022

Mary Jane Whiteley Coggeshall, Hicksite Quaker, Iowa/National Suffragette And Her Speeches

Mary Jane Whiteley Coggeshall, Hicksite Quaker, Iowa/National Suffragette And Her Speeches
by John N. (Jake) Ferris
October 2022

In It Together: The Beautiful Struggle Uniting Us All

In It Together: The Beautiful Struggle Uniting Us All
by Eckhart Aurelius Hughes
November 2022

The Smartest Person in the Room: The Root Cause and New Solution for Cybersecurity

The Smartest Person in the Room
by Christian Espinosa
December 2022

2021 Philosophy Books of the Month

The Biblical Clock: The Untold Secrets Linking the Universe and Humanity with God's Plan

The Biblical Clock
by Daniel Friedmann
March 2021

Wilderness Cry: A Scientific and Philosophical Approach to Understanding God and the Universe

Wilderness Cry
by Dr. Hilary L Hunt M.D.
April 2021

Fear Not, Dream Big, & Execute: Tools To Spark Your Dream And Ignite Your Follow-Through

Fear Not, Dream Big, & Execute
by Jeff Meyer
May 2021

Surviving the Business of Healthcare: Knowledge is Power

Surviving the Business of Healthcare
by Barbara Galutia Regis M.S. PA-C
June 2021

Winning the War on Cancer: The Epic Journey Towards a Natural Cure

Winning the War on Cancer
by Sylvie Beljanski
July 2021

Defining Moments of a Free Man from a Black Stream

Defining Moments of a Free Man from a Black Stream
by Dr Frank L Douglas
August 2021

If Life Stinks, Get Your Head Outta Your Buts

If Life Stinks, Get Your Head Outta Your Buts
by Mark L. Wdowiak
September 2021

The Preppers Medical Handbook

The Preppers Medical Handbook
by Dr. William W Forgey M.D.
October 2021

Natural Relief for Anxiety and Stress: A Practical Guide

Natural Relief for Anxiety and Stress
by Dr. Gustavo Kinrys, MD
November 2021

Dream For Peace: An Ambassador Memoir

Dream For Peace
by Dr. Ghoulem Berrah
December 2021