Setup and Rule Diagrams

[willmcchez]

Just a quick question on the step-up here. I set it up as an In/Out game, meaning I made four dashes representing the four attendees, then three dashes representing those who were not attending (separated by a bold line between the two groups). I'm really struggling with this game, especially because it appears to be easy. I don't know if its my setup or I've just been staring at it for too long.

[Francis O'Rourke]

Hi Will,

That is extremely close to how I would set up this game. Since you are having a lot of difficulty with this one, try to give us more details so that we can help you out better!

[nzLSAT]

I incorrectly made the assumption that the diagram for the rule "N cannot be selected unless L is selected" and "Q cannot be selected unless K is selected" to be:

"If L -> N"

and

"If K -> Q".

I thought they were both diagrammed like this because it's saying that "If L is selected, then N can be selected," for example. I understand that this is a mistaken reversal. How can I make sure not to make this same incorrect assumption again?

[Rachael Wilkenfeld]

Hi nzLSAT,

Remember that unless is showing you the necessary condition. "N cannot be selected unless L is selected" means that L is necessary, and N is sufficient. We diagram this the same way we diagram any unless statement. The part modified by the term unless is necessary, and the other term is negated and put into the sufficient slot. That's why it becomes

N L

and

Q K.

In both rules, the rule is telling us that the L and the K are needed in order for the other term to be selected. N cannot be selected unless L is selected means the ONLY way you can get N is if you have L. L is required to have N.

It might help you to brush up a bit on conditional statement diagramming. We mostly stress it in logical reasoning, but the conditional rules still apply here in the games.

Hope that helps.

[concrottrox11@gmail.com]

If you were to draw a deduction from N-->L--->not P, can you explain how you would get to the final deduction? I read on the thread above that the deduction was "Some Ls with not P", but I do not understand this deduction. Can you please explain how the above "Some Ls with not P" deduction was deduced and why it was deduced as well?

Thank you.

[Dave Killoran]

If you were to draw a deduction from N-->L--->not P

Hi C,

Thanks for the question! You can't draw this deduction was actually my point The point reference to the "some" inference--which is typically useless in LG--was a separate aside for those who wonder if there is any connection at all between those variables. Yes, there is, but it's not a traditionally useful LG inference.

Thanks!

[TSimmons]

Hi all,

I'm reviewing some LG questions, and I had interpreted this up as a template problem and drew out the following templates using j/k and n/p rules:

IN: J P M L │ OUT: K Q N
IN: J N M L │ OUT: K Q P
IN: K P (2 of L M Q) │ OUT: J N (1 OF L M Q)
IN: K N L M/Q │ OUT: J P Q/M

This had allowed me to solve a number of the problems, but it became quite cumbersome looking through the patterns to ans the questions. I recognize that the methods described in the set-up and individual forums for this question go about this differently, and seemed to arrive at ans w significantly less difficulty/ maneuvering.

Are there any rules of thumb where we can distinguish when and for what problems we template/ follow a more standard not-law diagram? I typically invest more time in templating bc templates yield quicker answers, but this time around it seemed to be much more time consuming/ and doing both is out of the question. Could we have used templates to solve this?

Thank you so much,
Toby

[Rachael Wilkenfeld]

Hi Toby,

The issue is always one of seeing if the investment pays off. You invest time in templates, and you want them to pay off in some way in the question. So if your templates make your question answering significantly faster, then you should do templates. If they don't, you shouldn't.

In this case, the set-up without templates is very fast, likely under a minute. The templates will likely take more time, and at least in the templates with K, yield minimal inferences. The two templates with J give a bit more information, but still, nothing that we didn't know from the fast setup. In this case, the templates would be useful with unlimited time, but I wouldn't use them here.

One situation where I would use them in this game would be if I was not comfortable using conditional reasoning quickly. In that case, it would be worth it to make sure you don't make a conditional error. The time spent on the templates would likely be less than the time you would need to slowly and carefully work with the conditional on every question. However, ideally, by test day you will be comfortable enough with conditionals that you would be able to do this set up without templates.

Hope that helps!