#HELP #help Confused by Invalid Forms 6 of 7

themikeryu2

Could someone explain to me the difference between how to identify a valid versus a invalid forum. When I physically write out the concepts I do not understand how to identity (when written out or in my head) if it is valid of invalid. For example:
Most runners buy running shoes. R-->S
Most people who buy running shoes don't like to run. S --> /L
Some runners dont like to run.

This is my drawing
S
S (maybe its here too /L)
S/L
S/L
SR (maybe its here too /L)
SR
SR
R
R

My question is how to identity the scope. You can obviously say that there is a chance that there is no runners who do not like to run but there is also a chance that they do. How do I identity when it is in or out of the scope. I would really appreciate and explanation with examples .

https://7sage.com/lesson/invalid-argument-form-6-of-7/?ss_completed_lesson=1151

luffyyyy

So using your example, we have R --m--> S --> /L. The valid conclusion we can draw is most R are /L. Let's say we have 3 R's. Most R's are S means at least 2 of my R's are S's (more than half). I then know that all of S's are /L. So if I see S then I need to see /L. So is it true that there's some overlap between R and /L? Yes, that has to be true. It's also true that most R are /L. That's why the valid conclusion we can draw is most R's are /L.

R
R S /L
R S /L
S /L
S /L

I think for your scope question, those are CBT, and not MBT. I have the drawing of 5 R's and 6 S's. If I see S then I must see /L. but I can have a lot more /L without S. Sure, there can be runners who like to run. But is that MBT according to our sets? No, it's not because there is no guarantee that these two sets overlap. It is a CBT. There is no guarantee that we will get an overlap between R and L, but we are guaranteed an overlap between R and /L.

R
R
R S /L
R S /L
R S /L
S /L
S /L
S /L
/L

I hope this helps a bit!

themikeryu2

@luffyyyy said:
So using your example, we have R --m--> S --> /L. The valid conclusion we can draw is most R are /L. Let's say we have 3 R's. Most R's are S means at least 2 of my R's are S's (more than half). I then know that all of S's are /L. So if I see S then I need to see /L. So is it true that there's some overlap between R and /L? Yes, that has to be true. It's also true that most R are /L. That's why the valid conclusion we can draw is most R's are /L.

R
R S /L
R S /L
S /L
S /L

I think for your scope question, those are CBT, and not MBT. I have the drawing of 5 R's and 6 S's. If I see S then I must see /L. but I can have a lot more /L without S. Sure, there can be runners who like to run. But is that MBT according to our sets? No, it's not because there is no guarantee that these two sets overlap. It is a CBT. There is no guarantee that we will get an overlap between R and L, but we are guaranteed an overlap between R and /L.

R
R
R S /L
R S /L
R S /L
S /L
S /L
S /L
/L

I hope this helps a bit!

So are you saying it could be true but not guaranteed to be true? I am confused about how it is valid then.