Tag Archives: Fallacy of Division

Logical Gal and the Fallacy of Division

22 Nov

XYZ is an efficient company, therefore, Joe Blow who works there must likewise be efficient.

Ah, but must he?  Maybe the organization is SO well run, that it can compensate for the drag that a poor-performing employee might add.  Welcome to Fallacy Friday and a trap we can fall into from time to time – the Fallacy of Division.

By definition, this error in thinking occurs when we identify the attributes of a larger whole and assign the same ones to its constituent parts.   It could be that a member of the whole shares the same qualities, but it’s faulty thinking to assume that is always the case.  Consider the color palate.  You might have a blob of black paint.  Is every drop of paint black?  My colleague, the art teacher, tells me that mixing bits of all the colors makes for a blackish brown yucky color.

Many other examples abound and are equally false.

So what’s the big deal, other than the possibility that the assumptions might not be true?

It’s the curse of expectations.  Suppose that  I’m familiar with Starbucks and their corporate culture  to train efficient AND personable baristas.  If I commit the Fallacy of Division, I can set myself up for disappointment. When I stop by one of the ubiquitous cafés and an employee is cold to me, then I’m likely to feel less satisfied. I’ve assumed that an intentional corporate value is held by each individual.  (unlike the expectation of some who travel to New York City or Paris and are braced to run into ‘rude’ people)

Another example we can look to is the pleasing musicality of an orchestra, or the satisfying visual treat of an Impressionist painting like this canvas by Georges Seurat.

The ensemble of paint dots or musical instruments working together produce a result that can’t be divided. That means isolating one violin playing its part might be boring.  Or 50 painted pointy strokes might not have any pattern.  But 20,000 points of color actually create a recognizable design.

I live in the greater Asheville area in Western North Carolina.  This artsy town is known for some questionable moral values and very liberal political views.  But we live here, too.  And we’re fairly conventional and Biblical in our assessment of right and wrong . We also  hold a mixture of politically conservative and libertarian views.

A quick passing judgment might look like this:

Asheville is a liberal, artistic,  fit, laid-back, ‘foody’, sexually-progressive town.

Logical Gal lives in Asheville

Therefore, Logical Gal must also be a liberal, artistic, fit, laid-back, sexually-progressive ‘foody’

Not so. SOME of those adjectives might apply.  But you would be incorrect to assume that every citizen of Asheville can be described in the same way as the town itself. (I’ll leave you to sort out a full description of Logical Gal)

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!