Supply the missing premise that makes the conclusion follow logically:P: X–some–YP: ?C: Z–some–Y

Ravi June 25, 2019

@cshoopman99,

Great question. I recommend reviewing our video lesson on quantifiers,
as it'll help you understand what "some" means more.

"Some" just means that some of one thing is also another thing.

Some basketball players play in Europe

basketball players - some - Europe

It could be true that 10% of basketball players play in Europe and
only 1% of people in Europe play basketball. However, we know for sure
that there is some overlap between these groups, so this is why "some"
statements are reversible.

Europe - some - basketball players

For the question you're asking about, let's take a look.

P: X - some - Y
P:
C: Z - some - Y

how can we connect the premise to the conclusion? That's what we need
to be thinking about.

We need some sort of relationship between X and Z

If all Xs were Zs, then some Zs would have to be Ys because we already
know that some Zs are Ys.

X - >Z

P: X - some - Y
P: X - >Z
C: Z - some - Y

Let's say there are 100 Xs, and 1 is a Y.

Every single one of those Xs is also a Z.

From this, we know there is at least 1 Y that is also a Z, and this is
why we can conclude Z - some - Y.

Does this help? Let us know if you have any more questions!

Blue3 January 12, 2021

This was a great explanation, thank you!

juliekatt October 31, 2021

This makes zero sense. How can an X also be a Z? It either is or is not. Why not say there are 100 XZs? Then how can there be one Y out of them??

Ravi February 7, 2022

@julieklatt, think of X and Z as real world things. X could be people who live in Idaho and Z could be people who live in the USA. In this case, all Xs are Zs because all people who live in Idaho live in the USA.

Keep in mind though that not all Zs are necessarily Xs. Not all people in the USA live in Idaho. Thinking of quantifier statements in real world terms can be very helpful in gaining more fluidity with them.

There isn't necessarily only one Y out of the Xs; there is at least one since we have a "some" statement. "Some" means one or more, so there has to be at least one.

Andre August 8, 2024

Not sure how along ago this was asked but some actually is in the powerscore book when they discuss some and most diagramming in chapter 13 "Formal Logic" of the book. They teach it a little differently than on here but it's effectively the same idea.

Emil-Kunkin August 11, 2024

And to add to this, don't be afraid to differ your style based on what works for you!