lr bible pg. 506

[kristinaroz93]

lr bible page 495: For the problem "People who are good at playing the game drackery..."

For choice A: "People with long legs make good runners. Everyone in Daryl's family has long legs. Therefore, Daryl would make a good runner". --> The bible says the reasoning is valid here since we assume that the term "family" includes Daryl. (But either way we took a whole and assumed the part was included)

However, on page 506 of the bible we see this problem "The student body at this university takes courses in a wide range of disciplines..."
And for this problem, the reasoning is invalid due to a whole to part flaw.

1)But just as in the first case isn't Miriam just as a part of the student body, just as Daryl is a part of the "family" in all respects? Or is the reasoning for the second example invalid because it doesn't say "every member of the student body", and so Miriam is not necessarily included in the whole unless we specify exactly that EVERY member of the student body takes courses in a wide range of disciplines, as in the first example given (i.e. the first example references that EVERYONE in Daryl's family had long legs, so we knew Daryl was part of this group).

2)And so with the term "everyone" used in the example on 506,would the reasoning there be valid, and consequently choice a correct?

3)What is the difference between these two examples that makes one valid and the other not? (Maybe "student body" is more of an entity whereas saying "every member of Daryl's family" is still referring not to a whole entity but parts of a group. And thus you are still going from part to part in the first example and entity to part as in the second. Is this it?)

I hope my confusion makes sense, because I do not want to mess something so silly as this up in the future! Thanks in advance!

[Dave Killoran]

Hi Kristina,

Thanks for the message! The set of questions you ask here are good ones, and hopefully if we can clear this up, it will help you with other problems as well. The discussion you've raised focuses on what really is the collective and what is the individual. In each of the examples you've cited, LSAC has very carefully made distinctions between the two, and when that occurs, recognizing those is crucial to your success (you did this in retrospect,as I'll note below). So, I'm going to pull out the sentences you cited, and highlight the sections in each that are important, and then comment on each.

• "Everyone in Daryl's family..."
  
  Ok, you can see how they set you up here, because there is mention of "Daryl's family" which is the whole. But, the sentence actually refers to all of the individual members, because it references "everyone in." That means that each member of the whole has the characteristic. So the connection here is part-to-part, and that allows the argument to make sense.
  
  
  "The student body at this university..."
  
  Now we have a reference to the collective (the "student body"). There's no reference to individuals inside that collective, just that the whole has a certain characteristic (takes a wide range of courses). So, when we continue on and get to Miriam, we have a classic part-to-whole error because we don't know if the individual parts have the same characteristic as the whole. You rightly noticed this in your analysis in point 1. The key thing is to recognize it while you are reading because the phrasing there is critical to making one valid reasoning and the other invalid.

Please let me know if the above helps. I'm hoping that this discussion will help resolve all three of the points you posed, and also make you more sure of yourself as you move forward. Thanks!

[kristinaroz93]

Hi Dave,

Thanks this does clear things up! But just to make sure everything is crystal clear, had it said "every memeber of the student body", this would be a part to part movement correct? And A would be the correct answer for that problem?


-Kristina

[Dave Killoran]

Yes and yes. Thanks!

[kristinaroz93]

=)