A concept that I found interesting in chapter 8 was about valid and invaild forms of using all.
The direct way of reasoning with all:
All S are P
a is S
So a is P
All S are P + a is S ---> a is P ======== VALID
Arguing backwards with all:
ALL is S are P
a is P
So a is S
All S are P + a is p ---> ======== USUALLY WEAK
Here some examples:
In all countries in southern Europe it is pretty warm during summer.
Spain is in southern Europe.
Therefore, in Spain it is pretty warm during summer.
All flowers are animals.
All animals can jump.
Therefore, all flowers can jump.
All mall are huge.
Westfield Oakridge is a mall.
So Westfield Oakridge is huge.
All cats are ugly.
Bob is a cat.
So Bob is ugly.
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I like how you simplified using the S and P claim like the text showed by either being "valid" or "usually weak."
ReplyDeleteIt was easy to follow and grasp.
Your examples were all well stated! I enjoyed the one on all flowers are animals and how all animals can jump which then leads to the conclusion that all flowers can jump. I thought that was funny but great example because that makes us think twice of what we have said before. It could have came across like that as well.
The comparison on malls being huge and using Westfield Oakridge because that mall is not as huge as the Great Mall in Milpitas or even as "huge" as Westfield Valleyfair. Good examples overall : )
I also enjoyed your examples. The example about the flower was interesting in pointing out why the backwards argument might be weak.And I love the image. I was puzzling - why is it weaker? If it works one way, it should work the other. But because flowers are not animals, it left me searching for another example.
ReplyDeleteAll papers are flat.
A slice of cheese is flat.
So, a slice of cheese is paper.
Hmmmmmm. You can get tied up in knots with this stuff.
I actually agree with the posts above mentioning how the examples and the way the explanation is formed. I found also that there are weak and valid forms of this argument to be unique. Here are some of my examples that I found useful:
ReplyDeleteAll American cars will not last very long.
My dad's car is American.
My dad's car will not last very long.
This example shows how each American car will not last very long, just like my father. Another example would include the following:
All dogs bark loudly.
My neighbor has a dog.
Therefore, my neighbor's dog barks loudly.
In this example it shows a weak argument because my neighbor's dog rarely barks.