Some vs. some of

[Roaks]

Re http://powerscore.com/lsat/help/lsat-qu ... nology.cfm

In regards to "some". If you say "I have some friends coming over", some can in fact mean all, as you have stated. However in your example you say "some of my friends are coming over" and in this instance it cannot be all. By putting "of" after some the meaning has changed to a portion of your friends, so, "some of my friends are coming over cannot mean all". Is this an error on your part or in fact are you saying that "some of" can mean all?

[Jon Denning]

Hey Roaks,

Thanks for the message and welcome to the Forum!

Actually, if you read that "some" paragraph closely, the point it's making is that "some" simply means "at least one" on the LSAT, and doesn't necessarily preclude "all." That is, "some" (or "some are") does not inherently imply "...but not all' ( or "some are not").

So our example of "some of my friends are coming over" is given to show that that could indicate that "all of my friends are coming over." Specifically, that paragraph states:

"For example, if you tell your roommate that “some” of your friends are coming over to watch the game, most of us assume that means that not all of your friends are coming (otherwise, why wouldn’t you have said that all of your friends were coming?). But, logically speaking, “some” can include “all,” so in the LSAT world, it may be that all of your friends are coming over."

There's no difference between the two "friends coming over" phrases that you give; both could include "all." Just think of "some" as equivalent to "at least one" (or "some of" as "at least one of") and you should be good!

Thanks!

[Roaks]

Thank you for your prompt reply. I am currently teaching English and have been unable to think of any scenario where "some of" could apply to "all". I had actually hoped that someone would respond with an example of how "some of" may possibly be used to refer to all, not only for LSAT but for my English students as well. My question dealt only with the difference in meaning between "some" and "some of". I have always taught that while "some" could mean "all", that some "of", could not, because the addition of the word "of", changes its meaning any amount except "all" (and zero).

This is perhaps a minor point, but I am aware of the importance in law of every word. Would you know of someone that I could contact in order to get an understanding of this issue rather than just memorize that "some of" in some situations may mean all.

[Nikki Siclunov]

Roaks,

Let me jump in real quick: remembering that "some" could possibly be inclusive of "all" is important primarily in the context of Formal Logic, where "some" and "all" play a precise, pre-determined role. For instance, knowing that "some cats are black, and all black animals are terrifying" allows us to conclude that some cats are terrifying. We don't know if some cats aren't black: they all could be black, every single cat more terrifying than the other.

Now, it's important to look at these statements in context. "Some of" is rarely a construct employed in Formal Logic for the purposes of making logical inferences, as described above. More often than not, test-makers use "some of" in the everyday sense of the phrase, as in "some of the most prominent scientists believe that global warming is a serious problem." It's possible they all believe this, which is why we can't infer that some prominent scientists do not believe in global warming. However, test-makers are highly unlikely to test you on this, as this is not the typical phrasing used in a formal logic problem.

Context is everything. If I wanted to clarify that "some" excludes the possibility of all, I'd use the word "only" as a modifier: "only some of my cats are black." Clearly, in this case we can make a reasonable inference that some of my cats are not black.

Hope this clears things up, and puts your mind at ease

[Jon Denning]

No problem! And let me follow up on Nikki's point.

First, sorry if that reply wasn't clear, although I'm not exactly sure how to phrase it differently: the example we gave on that webpage, and that I quoted, uses the phrase in question "some of" (in "some of [my] friends are coming over to watch the game") and, again, that absolutely could include "all." "Some" and "some of" are therefore functionally equivalent on the LSAT in terms of what they do and do not potentially indicate.

Nikki's point is an excellent one, in that he distinguishes between the two based on how/where they are traditionally tested, and what you would likely be asked to do with "some" statements in Formal Logic vs elsewhere. I'll add to that two points:

1. The linguistic interpretation of either statement, "of" or no, is still the same. You might be asked in Formal Logic to utilize a more mathematical-type reading, but "all" is still possible in either case.

2. They could still test the idea of "some of" potentially including "all" in places other than Formal Logic, and I've even seen them do it (even though it's less common than Formal Logic "some" as Nikki points out). That is, a statement like "some of the contaminated water has made its way into the reservoir" could easily have an incorrect inference answer choice that says "some of the contaminated water has not yet made its way into the reservoir." Why is that incorrect as a certainty? Because "some of it has" can potentially mean "all of it has," hence we cannot infer "some of it has not."

Finally, I think you've contacted the right people if you're looking for a better understanding of the LSAT (uniqueness of LSAT language or otherwise). Hopefully this helps you better understand the issue

[Roaks]

Thank you both so much for the assistance.