TOUGH Conditional Statement with Confusing Indicators HELP!

youknowryan
Posts: 182
Joined: Mon Aug 18, 2008 3:20 am

TOUGH Conditional Statement with Confusing Indicators HELP!

Postby youknowryan » Mon Jan 03, 2011 3:25 pm

The following is an odd statement, since what appears to be the necessary condition is the sufficient:

"We can only win this battle if we receive more supplies."

This diagrams like so:
win -> supplies
~supplies -> ~win

My issue is how does one get there? Using standard indicator words, would make this statement look like this:
supplies -> win
~win -> ~supplies

The other trick I use is rearranging the sentence to an "if...then" format, but again this yields 2 reasonable possibilities:
I. If we receive more supplies, then we can win this battle.
II. If we win this battle, then we received more supplies.

When I am not rushed, I would pick the second as superior, but in the heat of an LR section, I can easily see one picking the first option only to regret it later.

Would someone dissect this statement and give some rules as to its handling?
Last edited by youknowryan on Mon Jan 03, 2011 3:29 pm, edited 1 time in total.

User avatar
magicman554
Posts: 201
Joined: Sat Oct 30, 2010 2:02 am

Re: TOUGH Conditional Statement with Confusing Indicators HELP!

Postby magicman554 » Mon Jan 03, 2011 3:28 pm

The first "reasonable possibility" is missing the "only," which makes it incorrect. There's your problem.

kcdc
Posts: 63
Joined: Tue Dec 28, 2010 1:28 pm

Re: TOUGH Conditional Statement with Confusing Indicators HELP!

Postby kcdc » Mon Jan 03, 2011 3:30 pm

If there is a win, then there must be supplies.

so,

win -> supplies

User avatar
magicman554
Posts: 201
Joined: Sat Oct 30, 2010 2:02 am

Re: TOUGH Conditional Statement with Confusing Indicators HELP!

Postby magicman554 » Mon Jan 03, 2011 3:34 pm

kcdc wrote:If there is a win, then there must be supplies.

so,

win -> supplies


Don't confuse OP.

OP, look for "only," "must," "cannot unless," and other related words/phrases when tracing necessary conditions. Look for "if" (without the "only") and related when tracing sufficient conditions.

User avatar
homestyle28
Posts: 2312
Joined: Thu Jun 04, 2009 12:48 pm

Re: TOUGH Conditional Statement with Confusing Indicators HELP!

Postby homestyle28 » Mon Jan 03, 2011 3:35 pm

kcdc wrote:If there is a win, then there must be supplies.

so,

win -> supplies

youknowryan
Posts: 182
Joined: Mon Aug 18, 2008 3:20 am

Re: TOUGH Conditional Statement with Confusing Indicators HELP!

Postby youknowryan » Mon Jan 03, 2011 3:38 pm

I get what the previous two posts are saying, my issue is this:

At a quick read, the statement looks like "supplies" are sufficient since "only" appears to modify win. How would one know to read the statement like this:

"We can win this battle only if we receive more supplies."

Here, the only is moved to make the "if" an "only if".

OR

"If we win this battle, then we received more supplies."

Here the "if" is moved to win, while the only is dropped completely.

How does one do this without changing the meaning of the sentence like this one? What's the rule?

User avatar
Nulli Secundus
Posts: 2625
Joined: Mon Jun 21, 2010 7:19 am

Re: TOUGH Conditional Statement with Confusing Indicators HELP!

Postby Nulli Secundus » Mon Jan 03, 2011 3:39 pm

youknowryan wrote:"We can only win this battle if we receive more supplies."


We take that only and put it here:

youknowryan wrote:"We can win this battle only if we receive more supplies."


Now it becomes an "only if", which makes the formulation as shown.

win -> supplies

youknowryan
Posts: 182
Joined: Mon Aug 18, 2008 3:20 am

Re: TOUGH Conditional Statement with Confusing Indicators HELP!

Postby youknowryan » Mon Jan 03, 2011 3:41 pm

nullisecundus wrote:
youknowryan wrote:"We can only win this battle if we receive more supplies."


We take that only and put it here:

youknowryan wrote:"We can win this battle only if we receive more supplies."


Now it becomes an "only if", which makes the formulation as shown.

win -> supplies


See my previous post, I got that. The question: when I see a form like this, is moving the only like you did always safe to do? The concern is running into a statement where doing that would change its meaning. See what I am getting at?

User avatar
Nulli Secundus
Posts: 2625
Joined: Mon Jun 21, 2010 7:19 am

Re: TOUGH Conditional Statement with Confusing Indicators HELP!

Postby Nulli Secundus » Mon Jan 03, 2011 3:42 pm

Do not get confused by rules too much, you should be able to tell if moving something from one place to another changes meaning or not.

In the given example, "we can only win if bla bla" means there is only one way of winning the battle and thus moving only before if does not change the meaning.

User avatar
magicman554
Posts: 201
Joined: Sat Oct 30, 2010 2:02 am

Re: TOUGH Conditional Statement with Confusing Indicators HELP!

Postby magicman554 » Mon Jan 03, 2011 4:03 pm

And by the way, "only" does not have to precede "if," as in the following example: "If we are to win the war, it will only be for the fact that we were well supplied."

You have to rephrase. Best way to look at necessary conditions is to do just that: think of the scenario abstractly, and find a relationship between things where one depends on the other. In this case, winning the war depends on being well-supplied, so being well supplied is the necessary condition.

User avatar
OnlyLivingBoyinNY
Posts: 90
Joined: Wed Jul 14, 2010 11:09 am

Re: TOUGH Conditional Statement with Confusing Indicators HELP!

Postby OnlyLivingBoyinNY » Tue Jan 04, 2011 5:32 pm

magicman554 wrote:
kcdc wrote:If there is a win, then there must be supplies.

so,

win -> supplies


Don't confuse OP.

OP, look for "only," "must," "cannot unless," and other related words/phrases when tracing necessary conditions. Look for "if" (without the "only") and related when tracing sufficient conditions.



While I agree that learning the indicators (can only a if b) is important, kcdc's simplistic reasoning makes a lot of sense: without supplies, there is no win. So, supplies is necessary, and win is sufficient.




Return to “LSAT Prep and Discussion Forum”

Who is online

Users browsing this forum: Tazewell and 18 guests