Struggling with Formal Logic

[sev3r]

Hey guys,

This might be a really basic question and I feel dumb here. But on one of the questions in the Logic Reasoning Bible it asks you to give inferences and diagrams of certain premises.

So it says:
Some T's are U's.
All U's are V's.
All T's are S's.

Final diagram I got right:
S <--- T some U --> V

However, one of the inferences is S some V!

I thought that is not necessarily true.

Let's say that there are two components of T, half which are made out of S (some S's are T's) and half of which are NOT made out of S. We know that some T's are U's. But let's say that the T's that ARE U's are composed only of the half that is not S's! This would mean, even though all U's are V's, there is no connection between U and S, and in this situation exactly 0 S's are V's.

I am probably have a flaw in my logic. Please let me know. Thanks.

[chike_eze]

Hey guys,

This might be a really basic question and I feel dumb here. But on one of the questions in the Logic Reasoning Bible it asks you to give inferences and diagrams of certain premises.

So it says:
Some T's are U's.
All U's are V's.
All T's are S's.

Final diagram I got right:
S <--- T some U --> V

However, one of the inferences is S some V!

I thought that is not necessarily true.

You should draw venn diagrams to see this. Sometimes it is difficult to see the overlaps literally. However, visual representations may be useful here.

Essentially, S and V overlap because T and U overlap, all of T is in S, and all of V is in U.

Therefore, some of S is V and some of V is S.