Deciphering Either/Or Statements

[amagari]

Hello,

How do I determine when to diagram "either/or" statements with

1. The special construction such as "Either John or Joe (at least one, possibly both) will go to the party." which would be
/John Joe
and
/Joe John

2. "To graduate from Throckmorton College you must be either smart or resourceful."

Which is diagrammed as
Graduate ( Smart OR Resourceful )

Since on the LSAT "either/or" means "at least one, possibly both" then phrase #2 should be diagrammed just like #1.

Please help me understand this.

[Adam Tyson]

The difference here, amgari, is in the presence or absence of some other condition that is sufficient to bring about the either/or situation.

In the first example, there is no other condition - there's only the either/or statement. Paraphrased, it's "if Joe doesn't go, then John does, and if John doesn't, Joe does". There's nothing else sufficient or necessary involved.

In the second example, there is some other condition at work - graduating from Throckmorton. IF that happens, then at least one of the other two things must happen, so if neither of those other two things happens then you don't graduate.

It's the difference between "either John or Joe must go" (there's no "trigger" for that choice - it simply must be made, regardless of anything else occurring or not occurring) and "if Mary goes, then either John or Joe must go" (where Mary going is the conditional trigger that requires that at least one of them go, and it could be that none of them go).

That special either/or relationship comes up more often in grouping games than in logical reasoning questions, so be particularly alert for it in that context, but it can occur in LR as well. Just look to see whether the either/or is an absolute choice that must always be made, or if there is some other condition that occurs that then forces us to make that choice.