Archive | October, 2013

Logical Gal says “Not even good enough to be a False Analogy”

7 Oct

This government shutdown has everyone mad, on both sides of the political spectrum.

But that is no excuse for lazy or poor thinking!  Actually, the only good excuse for faulty thinking, is that you haven’t been internalizing  these blog posts!

Last night, my husband read me a letter written to the editor of our local paper.  In it, the author compared the Republican Congress to a child who condemns his parent for not negotiating with him.  In the imagined scenario,  the youngster wants to stay up late and Dad says “No!”  The child then actually threatens to smash things in the house if he doesn’t get his way.  The letter writer asks rhetorically, ” What should the parent do?”

I’m sure he felt clever for creating this analogy.  But it fails.  It’s not even a PROPER false analogy.  Why not? The relationship between threatening child and firm parent is NOT at all similar to the relationship between the Republican-majority Congress and the President.  A twelve-year old who has had some civics could probably recall that our Founding Fathers created a system of checks and balances.  One of the attributes of the federal system of organizing government is that there are three branches:  Legislative (Congress), Executive (the President) and the Judicial (Supreme Court).  They are equal in stature.

The relationship of defiant child to firm father is not similar.  My dad would have accused the letter writer of  ‘comparing apples with oranges’.  Sure they are both fruits, but that is all you can say!

Back to our non-functioning  government.  All three branches are ON the same level. Therefore, the Executive branch AND the Legislative branch should strive to work together.  That is responsible government.  Isn’t that the expectation of ‘We the People’  who elect both the President and our Representatives?

So what is a False Analogy? – it’s a kind of faulty thinking that assumes that because two items have one characteristic  in common, they share others as well.  I think the letter writer painted a scenario that shows no similarity to our present crisis.

At best his example might be able to be worded like this:

Some kids defy their parents and parents should not give in.

Congress is defying the President 

Therefore, he should not give in

This is not even a GOOD false analogy!  The President and Congress are supposed to work together!!

(Thank you, Michael, for pointing out this example of poor thinking! I’m blessed to be married to a man whose first words in my presence were from Socrates: “The unexamined life is not worth living!”)

Logical Gal spots 2 fallacies in one syllogism

4 Oct

The other day I was listening to a radio program recounting a debate that had taken place in Australia.

One of the two debaters apparently resorted to name-calling and sought to be clever by doing so within a verbal syllogism.

And in the ensuing radio discussion about the quality of the debate, a listener pointed out there was a logic error within the syllogism.

Here is the syllogism (unfortunately it was intended to demean)

All mammals exhibit homosexual behavior

Joe is a mammal

Tf, Joe exhibits homosexual behavior

Can you identify the error?  You don’ t have to know anything about Joe’s sexual preferences to notice the problem.

Remember that a syllogism is limited in form by the requirement to have exactly 3 terms.  What are the terms in this one?

  1. mammals
  2. (that which)  exhibits homosexual behavior
  3. Joe

“ So…….??”  you say.

Here’s the problem: the term ‘mammals’  is actually used equivocally to mean two different concepts.

In premise 1, the term mammals really means species of mammals

So then in premise 2, mammals is used as a particular MEMBER of a species of mammals.

If we were to accurately state the premises and conclusion of the one advancing the argument, we would quickly see that he has used clever wording to cover up his Fallacy of Equivocation.  To reach his conclusion, he has to employ more than the 3 terms. (I’ve colored each term – only ‘ Joe’  is used twice.  We actually have 5 terms in this syllogism.

P1 – All species of mammals are species that have members that exhibit homosexual behavior

P2 – Joe is a member of a species of mammals that exhibits homosexual behavior

Tf – Joe is a mammal that exhibits homosexual behavior

And if that weren’t enough, he also commits the Fallacy of Division.  This happens when we assume that a quality of the group applies equally to every member of a group.

If we say “ Texas A&M sure is a passing team” in the sense that they pass the ball  a lot, it does not follow that every member of that team is a higher-than-average passer!

It may be that the Jones family is very artistic.   But Billy Jones is not necessarily artistic himself.  He might take after his great-great grandfather who played for Texas A& M!

A cake may be tasty, but each ingredient is not.  Have you ever snacked on butter? Do you see the fault in the reasoning?

Back to Joe and the name-calling debater.  Not only did his accuser have to cobble together multiple terms and then hide them, he also committed the Fallacy of Division and presumed to announce something about Joe that stretched beyond the known facts.

Remember, whoever makes the claim has to be able to defend his thinking!

Logical Gal and the Law of Excluded Middle

2 Oct

Have you ever been frustrated by someone’s quibbling?

Mom – “Who ate my chocolate?”

Kid – silence….Shrug of shoulder

Mom – “Listen, you either KNOW or you DON’T KNOW, which is it? “

Kids – “Maybe it just vaporized?”

Mom – “So you know!”

Kid – “I didn’t say I know.”

Mom – “So you don’t know!”

Kid – “I didn’t say that either,” whining because he knows he’s been caught by a logical mom!

Mom – “Based on the Law of the Excluded Middle, you have only 2 choices:  Either…….A – you know what happened to my chocolate .  Or……B – you don’t know…..Which is it, Buddy?”

Mom is relying on the 2nd of the 3 basic laws of Classical Thought – the Law of Excluded Middle.  (last time we talked about the Law of Identity)

This is very useful because it forces you to categorize an issue.   Something is either A or non-A.  There are no other choices.  This isn’t rocket science, just common intuition!

  • You’re either pregnant or you’re NOT pregnant (no such thing as a little pregnant)
  • My car is painted either black or non-black
  • You either speak Chinese or you don’t.  (What about if you speak just a little?  Then you speak Chinese!)

Turning to a deeper issue that often comes up, do you see how this law could help in a discussion about the existence of God? He either exists, or He doesn’t.  We might not know, but it’s either one or the other.

What other possibility could there be?  The picture below is TRYING to get you to think that there might be a 3rd choice, but there isn’t!   (the supposed 3rd option of ” Probably”  is meaningless!)

Here’s one guideline in organizing your either/or statement: 

  • Whatever predicate you are using, you have to frame it as A or non-A

You can’t say:  Either my car is blue or white.  That’s not true, for there are other possibilities.

So you would have to claim: “ Either my car is blue or it is non-blue”

What issues does the Law of Excluded Middle simplify for you?