[34iplaw]

If she owns, she also owns either Q or R. (pg 180)

Does either change or restrict the meaning of “or” here?

The solution shows S -> Q or R; Q and R -> S

Usually, S could cause Q, R, or Q&R. Does “either Q or E” restrict this to S causes Q or R but not Q&R?

If the latter, wouldn’t the contra positive be Q & R OR Q & R -> S ?

Basically, I’m wondering if either or on the LSAT basically means but not both

 

[34iplaw]

Replace cause with trigger. Posting from phone as I go so it’s a bit hard to edit posts. Apologies!

 

[LSAT Dan]

I don’t think that the appearance o the word “either” changes the general rule – if you’re not specifically told “but not both,” then “or” is inclusive. For instance, “To be accepted to college, one must have either a high school diploma or a G.E.D. Certificate” would not be logically incorrct and would not imply exclusivity. I haven’t checked, but with one exception, I strongly doubt there are any situations where it’s supposed to be the exclusive “or” and they don’t say “but not both.”

The exception would be situations where the inclusive ‘or’ would be impossible. For instance, in a 1-to-1 sequencing game where it says something like, “X is in position 3 or position 5.”

When I say “but not both,” I mean to include any such similar limiting language.

[Mike Kim]

Dan is right — the either doesn’t make the “or” exclusive and if they want the either/or to be exclusive they will say so (or it will, as Dan stated, be a situation that naturally limits the options).

 

 

[34iplaw]

Ok – understood.  I appreciate it.  I sort of meant to delete this, as I got to a page a bit later in the Trainer on that sort of explicitly stated what you have.

I think the reason it sort of confused me is that it was the only “either or” in the drill, if I recall correctly, so it kind of stood out.