Distinguishing "Either Or" as Inclusive vs. Exclusive

MattLaP323

I'm having difficulty distinguishing "either or" as inclusive vs. exclusive.

I'm working on the Advanced Logical Indictor section from the CC and immediately ran into confusion with the question 1 from the Complex Conditional Translation section.

For instance using Q1 from that section:

If a cat weights over 10kg, then it is either a Maine Coon or suffering from obesity.

I was confident at first that the sentence could be translated to:

10kg+ → (/MC→SO) = 10kg+ and /MC →SO

But as JY and other users comments detailed, this interpretation is incorrect because I'm incorrectly presuming the "either or" is an embedded bi-conditional.

So to clarify, if the sentence does not explicitly state "but not both" and if there's no context that can be used to determine if the "either or" is inclusive or exclusive, should I default and interpret the "either or" to mean inclusive?

In this instance, since Q1 does not explicitly state "not both" and there's no additional context, is it reasonable to interpret the "either or" as inclusive?

Making the logical translation as such:

OG: 10kg+ → MC or SFO
If a cat is over 10kg, then it's either a Maine Coon or suffering from obesity.

Contrapositive: /MC and /SFO → /10kg+
If a cat is not a Maine Coon and not suffering from obesity, then it's not over 10kg.

I'm just trying to really hammer home and flesh out the difference between inclusivity vs. exclusive.

Any Reply or input would be greatly appreciated! Thanks!!

#help

LSAT Lizard

The answer is yes. If you do not have additional context like 'but not both' then you can always safely interpret 'or' as being the 'inclusive or.'

There's a 7sage lesson on this topic here. It goes into depth on why this question is such a valid thing to wonder about, but overall the answer ends up being:

Remember the rule of thumb is to read them like in sentence (1), the inclusive usage of the word. If the LSAT wants to communicate the "and" (incredibly rare) meaning or the "exclusive or" meaning (this happens often enough), it will be explicit and the context will disambiguate.

I think the only way that JY has arrived at the answer is really just to empirically observe that this is how the LSAT handles it. They could've chosen a different interpretation of 'or' to be the default / no context interpretation, and the 'inclusive or' just so happens to be the default that they chose.