Weakening Conditionals

[voodoochild]

Weakening Conditional statements --- If I want to win the yearly elections, I will need to do honest campaigning

This doesn't weaken : "If I want to win the yearly elections, I will place an Ad on Facebook" because it keeps the possibility of honest campaigning through FB.

Generally, there could be 100s of necessary condition. However, how would I say that the necessary condition is THE ONLY necessary condition? i.e. if I want to say that placing an Ad on FB is THE ONLY necessary condition?

[Jamie Caulkins]

If we are trying to weaken the conclusion that "If I want to win the yearly elections, I will need to do honest campaigning," the best bet is find a circumstance where a politician wins an election in spite of some dishonest campaigning (in other words, show that the necessary condition does not have to happen for the sufficient to occur). Remember, pointing to, let's say, Vladimir Putin as a candidate who won election despite dishonest campaigning (just a hypothetical here) doesn't destroy the argument--maybe there is something different about the election in the stimulus- but it does weaken the idea that dishonest campaigning is a dealbreaker when trying to win an election.

To make a general note on prephrasing, it isn't necessarily our job to come up with the Putin example, because chances are the test makers won't have the exact same weakener example in mind, but our job instead is to know what to look for so that when we encounter the Putin example, we know whether it is our answer or not.

I am not sure I understand your last question, but to make an ad on Facebook the only condition, you would need to change the stimulus statement to "If I want to win the yearly elections, I will need to advertise on Facebook, and only on Facebook." Can you think of an example of what would weaken that?

[voodoochild]

Jamie,

Thanks for your reply. I am not sure whether I understood your response about weakener.

Isn't it required that to weaken a conditional, we need to prove that suff condition holds good, but necessary doesn't exist.

In my example, "I won the elections by campaigning on FB" doesn't have any effect on the argument because this doesn't talk about "honest campaigning," which is a necessary condition. However, "I won the elections by campaigning on FB, a dishonest campaign against the rules of electoral commission" weakens it because necessary condition didn't happen ("honest campaign").

My second question was about only one "necessary condition"

For instance, IF I want to win an election, I should do honest campaigning. HEre, honest campaigning is ONE necessary condition for the sufficient condition ("win an election")

Similarly, IF I want to win an election, I should wear Stetson hat. Here, I have pointed another necesary condition. Hence, I could have infinite necessary conditions.

How would I write a sentence that has ONLY ONE necessary condition? For instance, (hypothetical case) If I want to physically land on the Moon, I would have to cross the Earth's atmosphere.

Any thoughts? Thanks

[Dave Killoran]

Hi Voodoo,

I think the issue here is that your original message wasn't very clear. But, that aside, a big part of your issue is that you have misunderstood what is needed to weaken a conditional statement (and this goes back to the discussion we had about negating statements recently).

You said: "Isn't it required that to weaken a conditional, we need to prove that suff condition holds good, but necessary doesn't exist." I've italicized the last part because that is not correct. You don't need to prove the necessary is nonexistent, just that it isn't necessary.

So, to weaken a statement such as A B, all you need to do is show that A can occur with B being present. Even just one occurrence will weaken that statement (even if it happens hundreds of other times that A and B occur together). Thus, if you go back to Jamie's response, you'll see that he properly references this fact.

I think the portion about the Facebook ads wasn't clear, so you probably need to clarify what exactly you were asking.

Thanks!

[voodoochild]

Thanks Dave. I see my mistake now.

Regarding the FB statement, my confusion was that in these two examples, the conditionality is the same but, I assume, the meaning is quite different.

Statement 1 : The only way to go to Virginia from NJ is to take IS 95.

From NJ to Virginia Take IS 95

Statement 2 : If you want to go to Virginia from NJ, then you must take IS 95.

From NJ to Virginia Take IS 95

However, statement 1 is telling me something about "the only" condition, i.e. I cannot walk, or take a flight. Taking IS95 is the only way to reach VA. However, statement 2 tells me that taking IS 95 is a necessary condition to reach VA from NJ, but I could also take "n" other ways (such as NJ -> California -> VA or NJ -> around the globe -> fly to VA) to go to VA from NJ. Is my understanding correct?

To restate my question, even though statement 1 and 2 have the same conditionals, but the meaning is quite different. Statement 1 tells me that IS95 is the only way to reach VA. Statement 2 tells me that IS95 is one of the many ways to reach VA, just that IS95 is a necessary condition. Is that correct?

Please let me know whether my understanding is correct.

Thanks

[Nikki Siclunov]

Let me jump in real quick here. To me, both of your examples about I-95 mean the same thing: to get to Virginia, you must take I-95. I don't believe, as you claim, that statement 2 allows for other ways to get to Virginia:

Statement 2 tells me that IS95 is one of the many ways to reach VA, just that IS95 is a necessary condition.

Look at your own statement closely and you'll see the internal contradiction: how can I-95 be a necessary condition for reaching Virginia, while also allowing for many other ways to get there? The very idea behind a necessary condition is that, well, it is necessary: it must be satisfied for the sufficient condition to occur. Part of your confusion, I suspect, is that you know (from the real world) of many other ways to reach Virginia other than taking I-95. But based on either statement alone, the only way to do so would be to take I-95.

Could there be other necessary conditions that must be met for you to get to Virginia? Yes, of course there are: neither statement 1, nor statement 2, precludes the possibility that you might also need to take I-278, a bunch of local roads, have a driver's license, or own a vehicle capable of traveling on a highway. Positing a condition as "necessary" does not preclude the possibility of there being other necessary conditions. To exclude that possibility, you need to say something like "You only need to do one thing in order to reach Virginia from NJ, and that is to take I-95."

Does that make sense?

[voodoochild]

Hello Nikki,
Thanks for your email. I am confused about two different statements written by you.

Statement1 :

The very idea behind a necessary condition is that, well, it is necessary: it must be satisfied for the sufficient condition to occur. Part of your confusion, I suspect, is that you know (from the real world) of many other ways to reach Virginia other than taking I-95. But based on either statement alone, the only way to do so would be to take I-95.

Statement2:

Positing a condition as "necessary" does not preclude the possibility of there being other necessary conditions.

If as per statement1, a necessary condition is the only way to do something, then there shouldn't be any other way to do that thing. Why? because the necessary is "the only way." Isn't it?

I am a bit confused. Please help. Thanks

[Steve Stein]

Hey voodoochild,

Let me jump in here as well--this issue is based on the subtle distinction between two uses of the term "only." When the term is used to introduce one necessary condition (of which there could be others), it means basically "under the following condition." For example, we could use the term to introduce the following two necessary conditions, for example:

You will do well on the LSAT only if you practice. (practice is necessary)
You will do well on the LSAT only if you use good prep materials. (good materials are necessary)

This is different from situations in which "only" means "sole," as, for example, when used to point to a single possible path, as with "Taking Main Street is the only way to get to the courthouse.

I hope that's helpful! Let me know--thanks!

~Steve

[voodoochild]

Steve,
Thanks for your reply. If I understand correctly,

#1:If you do well on the LSAT, then you would need to practice Here, the necessary condition "need to practice" is not THE ONLY condition.

#2:You can do well on the LSAT, only if you practice Here, the necessary condition "need to practice" is not THE ONLY condition.

However, #3: The only way to do well on the LSAT is to practice. Here, "practicing" is a necessary condition and is THE ONLY necessary condition. Essentially, my watching LSAT youtube videos (assuming that my watching videos doesn't involve practicing and "watching LSAT youtube videos" could be another necessary condition) wouldn't be necessary.

Am I correct?

Please let me know.

thanks

[Steve Stein]

Thanks for your response.

"The only way to do well on the LSAT is to study" is not a sentence that you would be likely to see on the LSAT--it sounds more colloquial to me, and it doesn't really make sense to claim that there is only one component to LSAT success; if you were to see something like that on the test, it would more likely be phrased "One can do well on the LSAT only if one practices." This spells out a necessary condition but allows for others as well.

I chose my example about a lone route to the courthouse on purpose--I think that the makers of the LSAT will make it very clear whether they are pointing to the sole avenue to a destination, or to one (of possibly many) necessities.

I hope that's helpful! Please let me know whether this is clear.

~Steve