# Logical Fallacies

**URL:** <https://boards.straightdope.com/t/logical-fallacies/17891>\
**Category:** Great Debates\
**Created:** [March 25, 2000, 6:59am UTC](https://boards.straightdope.com/t/logical-fallacies/17891 "2000-03-25T06:59:00Z")\
**Posts on this page:** 20\
**Page:** 2

<div class="post-metadata">

**Author:** ![Sterra](https://avatars.discourse-cdn.com/v4/letter/s/8c91f0/32.png) [@Sterra](https://boards.straightdope.com/u/Sterra)\
**Post date:** [March 28, 2000, 6:50am UTC](https://boards.straightdope.com/t/logical-fallacies/17891/21 "2000-03-28T06:50:00Z")

</div>

if you judge faith by a scientific point of view but not science from a faith point of view are you being unscientific? 🙂

---

<div class="post-metadata">

**Author:** ![SingleDad](https://avatars.discourse-cdn.com/v4/letter/s/9e8a1a/32.png) [@SingleDad](https://boards.straightdope.com/u/SingleDad)\
**Post date:** [March 28, 2000, 7:15am UTC](https://boards.straightdope.com/t/logical-fallacies/17891/22 "2000-03-28T07:15:00Z")

</div>

**Asmodean:** I will presume that you’re not just playing stupid semantic games but that you have a real point which I’m not comprehending. Care to elaborate further?

---

<div class="post-metadata">

**Author:** ![billehunt](https://avatars.discourse-cdn.com/v4/letter/b/c37758/32.png) [@billehunt](https://boards.straightdope.com/u/billehunt)\
**Post date:** [March 28, 2000, 7:57am UTC](https://boards.straightdope.com/t/logical-fallacies/17891/23 "2000-03-28T07:57:00Z")

</div>

I am an atheist and a strong proponent of logic. However, these sorts of discussions don’t really resonate with me since I’m not interested in pushing religous people to my way of thinking. I have plenty of people in my life who take great solace in their faith, and I respect that. Further, almost to the person, every **very** religous person I know is hardworking, moral and upstanding. I know plenty of lazy, immoral atheists (but not all, obviously). Though I’m not religous, I do sometimes wonder if our society would be better if more people were.

I think that applying logic to faith is impossible. Faith, by definition must be something which is not governed by the laws of logic (such as believing in things you can’t see), and extreme faith is **contrary** to the laws of logic (such as believing in walking on water or people being brought back from the dead). As a 20 year old, I used to love arguing with the [insert favorite sect]s who came to the door, because if you can get onto the logic playing ground you’ll always win.

Logic and Faith are by definition non-intersecting. I suspect this is what **Asmodean** meant.

---

<div class="post-metadata">

**Author:** ![JonF](https://avatars.discourse-cdn.com/v4/letter/j/cab0a1/32.png) [@JonF](https://boards.straightdope.com/u/JonF)\
**Post date:** [March 28, 2000, 2:40pm UTC](https://boards.straightdope.com/t/logical-fallacies/17891/24 "2000-03-28T14:40:00Z")

</div>

> [@](#):
>
> Science only advances by proving that it was wrong all along.  
> (help–what’s the actual quote, and from whom?)

“Science advances, funeral by funeral.”

Probably Max Plank, although I’ve seen it attributed to Bohr.

* * *

jrf

---

<div class="post-metadata">

**Author:** ![SingleDad](https://avatars.discourse-cdn.com/v4/letter/s/9e8a1a/32.png) [@SingleDad](https://boards.straightdope.com/u/SingleDad)\
**Post date:** [March 28, 2000, 4:04pm UTC](https://boards.straightdope.com/t/logical-fallacies/17891/25 "2000-03-28T16:04:00Z")

</div>

In keeping with the OP I want to mention a fallacy I’ve noted elsewhere. I’ve coined the term **argument from stupidity**.

This argument essentially boils down to: I don’t understand X, therefore X is false.

This fallacy differs from the classic **argument from ignorance** which has the form, “Theory X cannot predict phenomenon Y, therefore X is false.”

**JonF:** I agree completely. Logic and faith are tools for organizing our thoughts. They have vastly different purposes and different powers.

I freely admit that I **do not understand** the power of faith. For me to argue against it in that basis would indeed be to commit the fallacy of **argument from stupidity**.

But I do know that faith _lacks_ the power to _consistently_ separate true propositions from false. I _can_ argue that to use faith for such a purpose is as futile and ridiculous as to use a hammer to cut a 2x4 in half.

And yes, Jon, science does advance “funeral by funeral,” an amazingly rapid pace indeed!

* * *

If Cecil Adams did not exist, we would be obliged to create Him.

---

<div class="post-metadata">

**Author:** ![SingleDad](https://avatars.discourse-cdn.com/v4/letter/s/9e8a1a/32.png) [@SingleDad](https://boards.straightdope.com/u/SingleDad)\
**Post date:** [March 28, 2000, 4:10pm UTC](https://boards.straightdope.com/t/logical-fallacies/17891/26 "2000-03-28T16:10:00Z")

</div>

**billehunt:**

> [@](#):
>
> … every very religous person I know is hardworking, moral and upstanding.

This has not been my observation, unless you _define_ “religious” to mean hardworking, moral and upstanding. In fact, by that definition, _I_ am “very religious!” Otherwise, it’s very easy to fall into the **no true Scotsman** fallacy.

And I prefer to let a person speak for himself, rather than trying to determine the meaning from an ambiguous or poorly-defined argument. I want to make my own points, not someone else’s.

* * *

If Cecil Adams did not exist, we would be obliged to create Him.

---

<div class="post-metadata">

**Author:** ![handy](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@handy](https://boards.straightdope.com/u/handy)\
**Post date:** [March 28, 2000, 4:29pm UTC](https://boards.straightdope.com/t/logical-fallacies/17891/27 "2000-03-28T16:29:00Z")

</div>

Why is it ‘Logical Fallacy’ & not just ‘Illogical’? How does religion get into this?

log•ic "la-jik\ noun [ME logik, fr. MF logique, fr. L logica, fr. Gk logike, fr. fem. of logikos of reason, fr. logos reason — more at legend] (12c)  
1 a (1) : a science that deals with the principles and criteria of validity of inference and demonstration : the science of the formal principles of reasoning  
(2) : a branch or variety of logic \<modal logic\> \<Boolean logic\>  
(3) : a branch of semiotic; esp : syntactics  
(4) : the formal principles of a branch of knowledge  
b (1) : a particular mode of reasoning viewed as valid or faulty  
(2) : relevance, propriety  
c : interrelation or sequence of facts or events when seen as inevitable or predictable  
d : the arrangement of circuit elements (as in a computer) needed for computation; also : the circuits themselves  
2 : something that forces a decision apart from or in opposition to reason \<the logic of war\>  
lo•gi•cian \lo-"ji-shen\ noun

©1996 Zane Publishing, Inc. and Merriam-Webster, Incorporated. All rights reserved.

---

<div class="post-metadata">

**Author:** ![SingleDad](https://avatars.discourse-cdn.com/v4/letter/s/9e8a1a/32.png) [@SingleDad](https://boards.straightdope.com/u/SingleDad)\
**Post date:** [March 28, 2000, 5:10pm UTC](https://boards.straightdope.com/t/logical-fallacies/17891/28 "2000-03-28T17:10:00Z")

</div>

Logical fallacies are specific arguments that _sound_ plausible but really violate the formal rules of logic. Fallacy is indeed a form of illogic, but it has its own quirks and features.

This thread originally started to discuss the fallacies I observed in the Gun Control thread (or thought I did; as noted, Joe\_Cool’s response was actually on point and accurate). CalifBoomer dragged religion in.

I suspect he’s trying to have his cake and eat it too: He wants to justify his use of logical fallacy by falling back on faith when someone points out his reasoning is faulty. I can’t really be sure about this suspicion, because the gentleman does not always make his point of view crystal clear.

I originally created a thread, “Epistemology 101,” to discuss the differences in faith and reason, but without an actual controversy at its core, it quickly sank. I don’t mind revisiting the topic here.

* * *

If Cecil Adams did not exist, we would be obliged to create Him.

---

<div class="post-metadata">

**Author:** ![Gilligan](https://avatars.discourse-cdn.com/v4/letter/g/e0b2c6/32.png) [@Gilligan](https://boards.straightdope.com/u/Gilligan)\
**Post date:** [March 28, 2000, 8:27pm UTC](https://boards.straightdope.com/t/logical-fallacies/17891/29 "2000-03-28T20:27:00Z")

</div>

A minor quibble with that definition, SingleDad - “Logical fallacies are specific arguments that sound plausible but really violate the formal rules of logic.” Many fallacies don’t violate the _forms_; they are _valid_, formally speaking. But they are wrong for other reasons. For example:

If X then Y  
X  
therefore Y

is quite valid. But the problem with many fallacious arguments is that either one or both premises (“If X then Y” and “X”) are simply false. Most texts I’ve seen categorize the various Latin-named fallacies as either those of _relevance_ (premise 1 above is false) or those of _presumption_ (either premise is presumed true without support, or even the conclusion itself is presumed true and simply restated in the premises.) There is also the category of _ambiguity_ where the problem is in the language itself.

I only bring this up is that I think the reason these fallacies are so common is because the _form_ is usually correct. It is very easy to think, “my syllogism is valid, so I must be right.”

I did like the part about science, and I’m adding the Argument From Stupidity to my reference.

---

<div class="post-metadata">

**Author:** ![SingleDad](https://avatars.discourse-cdn.com/v4/letter/s/9e8a1a/32.png) [@SingleDad](https://boards.straightdope.com/u/SingleDad)\
**Post date:** [March 28, 2000, 8:56pm UTC](https://boards.straightdope.com/t/logical-fallacies/17891/30 "2000-03-28T20:56:00Z")

</div>

An amusing look at various “proofs”:

[Proofs that _p_](http://www.math.uni-frankfurt.de/~eik/fun/math/p.html)  
[More Proofs that _p_](http://coombs.anu.edu.au/Depts/RSSS/Philosophy/People/pproof.html)

**Plato:**  
SOCRATES: Is it not true that p?

GLAUCON: I agree.  
CEPHALUS: It would seem so.  
POLEMARCHUS: Necessarily.  
THRASYMACHUS: Yes, Socrates.  
ALCIBIADES: Certainly, Socrates.  
PAUSANIAS: Quite so, if we are to be consistent.  
ARISTOPHANES: Assuredly.  
ERYXIMACHUS: The argument certainly points that way.  
PHAEDO: By all means.  
PHAEDRUS: What you say is true, Socrates.

* * *

Do you believe in Rock ‘n’ Roll? Can music save your mortal soul? And can you teach me how to dance real slow?

---

<div class="post-metadata">

**Author:** ![Navigator](https://avatars.discourse-cdn.com/v4/letter/n/4af34b/32.png) [@Navigator](https://boards.straightdope.com/u/Navigator)\
**Post date:** [March 28, 2000, 9:50pm UTC](https://boards.straightdope.com/t/logical-fallacies/17891/31 "2000-03-28T21:50:00Z")

</div>

I like these:

**Wittgenstein’s Net:**  
Wittgenstein uses an image of a group of researchers, who are studying the size of fish in a certain pond. They use a net with a 2 inch mesh to drag the lake, and then pile the fish on the bank. Whereupon, they proceed to measure each fish VERY, VERY carefully with a ruler, and come to the startling conclusion that there are no fish under 2 inches long in the pond. (I have lost the reference to this in his corpus, in the intervening 20 years, but am trying to re-locate this.)

**Procrustes:**  
A mythical Greek giant who was a thief and a murderer. He would capture travelers and tie them to an iron bed. If they were longer than the bed, he would hack off their limbs until they fit it. If they were too short, he would stretch them to the right size. Using Procrustes’ own villainous methods, Theseus killed him.

_Procrustean operation:_ One that relentlessly tries to shape a person, an argument, or an idea to a predetermined pattern.

## Peace.

† Jon †  
Phillipians 4:13

---

<div class="post-metadata">

**Author:** ![SingleDad](https://avatars.discourse-cdn.com/v4/letter/s/9e8a1a/32.png) [@SingleDad](https://boards.straightdope.com/u/SingleDad)\
**Post date:** [March 28, 2000, 11:29pm UTC](https://boards.straightdope.com/t/logical-fallacies/17891/32 "2000-03-28T23:29:00Z")

</div>

From the Creationism - 3D thread, Gaudere offers a far superior term: **argument from _incredulity_** (I don’t understand X therefore X is false).

---

<div class="post-metadata">

**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\
**Post date:** [March 28, 2000, 11:56pm UTC](https://boards.straightdope.com/t/logical-fallacies/17891/33 "2000-03-28T23:56:00Z")

</div>

> [@](#):
>
> Originally posted by Joe\_Cool:
> 
> Science only advances by proving that it was wrong all along.

Often. But there is that little bit about also discovering stuff we didn’t know about before…  
-Steve

* * *

“Banned by the Space Pope”

---

<div class="post-metadata">

**Author:** ![SingleDad](https://avatars.discourse-cdn.com/v4/letter/s/9e8a1a/32.png) [@SingleDad](https://boards.straightdope.com/u/SingleDad)\
**Post date:** [March 29, 2000, 4:46am UTC](https://boards.straightdope.com/t/logical-fallacies/17891/34 "2000-03-29T04:46:00Z")

</div>

**wevets:**

> [@](#):
>
> But there is that little bit about also discovering stuff we didn’t know about before…

People are endlessly creative. We can create an infinity of hypotheses. The true strength of science is the process of weeding out the _wrong_ hypotheses.

* * *

Not one shred of evidence supports the notion that life is serious.

---

<div class="post-metadata">

**Author:** ![CalifBoomer](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CalifBoomer](https://boards.straightdope.com/u/CalifBoomer)\
**Post date:** [March 29, 2000, 5:20am UTC](https://boards.straightdope.com/t/logical-fallacies/17891/35 "2000-03-29T05:20:00Z")

</div>

Frankd6:

> [@](#):
>
> If you don’t believe in the power of logic, why waste your breath on an argument?

Logic is a _belief?_  
SingleDad:

> [@](#):
>
> This board is dedicated to the pursuit of rational inquiry.

A rational mind recognizes and acknowledges that it has limitations.

> [@](#):
>
> The rules of rational debate  
> are assumed here.

Exactly. I asked you to support your assumption as logical and valid. This you are unable to do. If you cannot support your starting premise, it follows that whatever may be derived from that premise may _or may not_ be valid.

Come on out of the cave and fight with the tools you’ve chosen.

::

---

<div class="post-metadata">

**Author:** ![NicePete](https://avatars.discourse-cdn.com/v4/letter/n/ee7513/32.png) [@NicePete](https://boards.straightdope.com/u/NicePete)\
**Post date:** [March 29, 2000, 5:20am UTC](https://boards.straightdope.com/t/logical-fallacies/17891/36 "2000-03-29T05:20:00Z")

</div>

**Lib**  
Thanks for elaborating on my example, to which I gave little or no thought.

My simple, if overly belabored point to the conspicuously absent CalifBoomer was this: Debate (or argument) is a process which relies upon the rules of logic to proceed. \*Debating \* the validity of logic is therefore at best inane and at worst comical.

* * *

Been here so long he’s got to calling it Home.

---

<div class="post-metadata">

**Author:** ![NicePete](https://avatars.discourse-cdn.com/v4/letter/n/ee7513/32.png) [@NicePete](https://boards.straightdope.com/u/NicePete)\
**Post date:** [March 29, 2000, 5:25am UTC](https://boards.straightdope.com/t/logical-fallacies/17891/37 "2000-03-29T05:25:00Z")

</div>

Talk about your ironic simulposts!

To respond:

I would submit that, yes, among other things, logic is a **belief**.

I have faith in the power and validity of logic. I believe in it. Therefore, my faith in the power of logic as a tool to evaluate the data my senses presented to me is a _belief_.

For what it’s worth, I would submit that empirically, logic is **by far** the best supported belief going.

* * *

Been here so long he’s got to calling it Home.

---

<div class="post-metadata">

**Author:** ![CalifBoomer](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CalifBoomer](https://boards.straightdope.com/u/CalifBoomer)\
**Post date:** [March 29, 2000, 5:52am UTC](https://boards.straightdope.com/t/logical-fallacies/17891/38 "2000-03-29T05:52:00Z")

</div>

Frankd6:

> [@](#):
>
> Debate (or argument) is a process which relies upon the rules of logic to proceed. Debating the validity of logic is therefore at best inane and at worst comical.

How is this _not_ circuitous? How is this not \*_argument from authority?_

and:

> [@](#):
>
> I would submit that, yes, among other things, logic is a belief.
> 
> ```
> I have faith in the power and validity of logic. I believe in it. Therefore, my faith in
> the power of logic as a tool to evaluate the data my senses presented to me is a
> belief.
> 
> ```

SingleDad sez:

> [@](#):
>
> An article of faith can never be proven true by an accumulation of evidence; it is  
> assumed to be true, regardless of evidence. It can never be proven wrong; contrary  
> evidence just causes additional convolution and rationalization of the faith.

You guys are a great team. You’re making my argument. Keep up the good work.

::

---

<div class="post-metadata">

**Author:** ![SingleDad](https://avatars.discourse-cdn.com/v4/letter/s/9e8a1a/32.png) [@SingleDad](https://boards.straightdope.com/u/SingleDad)\
**Post date:** [March 29, 2000, 6:06am UTC](https://boards.straightdope.com/t/logical-fallacies/17891/39 "2000-03-29T06:06:00Z")

</div>

Boomer, I will say this once here, since you didn’t have the guts before to take this to the Pit: Your comments are inane and incomprehensible, and I will waste no more time reading or responding to your posts.

If you like, however, I would be willing to take this to the Pit.

* * *

Not one shred of evidence supports the notion that life is serious.

---

<div class="post-metadata">

**Author:** ![CalifBoomer](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CalifBoomer](https://boards.straightdope.com/u/CalifBoomer)\
**Post date:** [March 29, 2000, 6:18am UTC](https://boards.straightdope.com/t/logical-fallacies/17891/40 "2000-03-29T06:18:00Z")

</div>

SingleDad:

I challenged you to support your statements and assertions using _your_ rules. Clearly, you are unable to do this. The mere existence of the conundrum I presented destroys your premise, and you know it. Your failure is not my fault. Either grow up, or find someone else to blame.

::

[Previous page](https://boards.straightdope.com/t/logical-fallacies/17891.md?page=1)

[Next page](https://boards.straightdope.com/t/logical-fallacies/17891.md?page=3)