Based on the passage, it can be concluded that the author and Broyles-González hold essentially the same attitude toward

joseph on December 10, 2017

again conditionals

there are a lots of conditional indicators in the last example as there are quantifiers. why did we or why are we not able to diagram any conditional for the question?

8 Replies

Mehran on February 10, 2018

Because of the quantifiers that also appear in these statements which takes them out of the S & N realm.

For example, "Only a few always do their own research before investing."

While this does have "only" it is not a S & N statement due to the presence of "few."

Hope that helps!

Robert on May 29, 2019

Hey, so I can get all the contrapostives from the drill practice I can get the premise contrapostives and the conclusion contrapostibes but I still don't know how to get the missing premise ?
d ->a
missing premise ? comes from where
Not x->a

Ravi on May 30, 2019


Great question. Let's take a look.

D - >A (not A - >not D)
C - >D (not D - >not C)
Conclusion: Not X - >A (not A - >X)

We need to add a premise that allows us to chain everything up.

not A - >not D - >not C

We need to go from not A - >X, so if we add not C - >X, we can arrive at
our conclusion.

The missing premise is not C - >X (not X - >C).

Does this make sense? Let us know if you have any questions!

Robert on May 30, 2019

on the missing premise do we just put in X
from the contrapostives could it be not a ->not d->not c->x

basically you are just working from the contrapostives and trying to link the first cp with the last and link them

Ravi on May 31, 2019

@sigmajonez14, right. We look at the original and the contrapositive for each premise and the conclusion and figure out how to best chain it all together.

on July 4 at 09:49PM

Just for clarification, we cannot reverse and negate the "some" quantifiers, correct? (example 1)

example: WMBC - some - PC

Cannot be written = not PC - some - not WMBC


on December 8 at 09:16PM

Question 6 has both without and only statements, which should introduce a S&N statement. How do we know (other than the context of the lesson) that we should diagram these clauses as most statements rather than S&N statements?

Ravi on February 5 at 12:17PM

@JTempleton88, that's correct.

@Jolson0023, we know we should diagram these clauses as most statements because even though they have without and only statements, they also include the word "most." Any time you see a quantifier, you know the sentence you're looking at needs to be diagrammed as such.