# Advanced Topic: Focusing on what must be for Logic Games

• November 7, 2016 at 11:56 am #2834
Mike Kim
Keymaster

During the course of setting up Logic Games and solving Logic Games problems, you end up having to work out various hypothetical situations, some with the mindset of trying to figure out what must be (must be true or false), and some with the mindset of what could be (what could be true or could be false).

Those of you who have read through the Trainer know that I emphasize prioritizing what must be (must either be true or false) as opposed to what could be.

I recently got an email question about why I recommend such strategies and I figured it might be helpful for me to share my answer publicly.

Please keep in mind that this is the type of meta consideration that often isn’t necessary for doing well on Logic Games — a lot of you do this naturally without thinking about it, and, even if you don’t, thinking about games in this way may or may not be of use to you.

However, I do feel certain it is, ultimately, a better mindset, and, for certain students, especially those at the highest levels, thinking about Logic Games in this way can help make it less likely that one will make preventable mistakes, and that one will waste time doing unnecessary work / thinking about unnecessary things.

Here are the reasons why I think focusing on what must be is to your advantage.

Premise 1: Logic Games are designed, by their nature, so that we can know certain characteristics about the situation, but not others.

Premise 2: When we think about a Logic Game and diagram it, our nature is to focus on what must be.

Consequences:

If you’ve understood and set up a game correctly,

1) Your knowledge of what must be (true or false) will be correct but incomplete.

You can trust that your understanding of the rules and your diagram represent true information, and, in addition, it’s very likely you’ve missed an inference or two, and it’s also certain you haven’t diagrammed every single possible inference you could make (that would take forever and not be particularly useful).

So again, correct, but, but it’s nature, incomplete.

2) Your knowledge of what could be (true or false) will be far more vague, and less reliable.

This is due to a variety of factors, but mainly this is due to the fact that you simply haven’t put as much energy into considering uncertainties as you have the must-be info, and that the “could be’s” are, in your diagram and in your mind, mixed together with all the “must be” inferences you either didn’t figure out or haven’t accounted for.

So, when it comes to thinking about problems and evaluating answers, it makes sense to rely first on that which will be more accurate (your understanding of what must be) rather than that which is less so (your understanding of what could be).

How this plays out on the actual exam:

Let’s imagine we’ve been given a “must be false” question.

We can either:
a) try to figure out what has to be false per our diagram or
b) try to eliminate answers by trying to see whether they could be true.

Again, per how we think and how we play games, we can know with a lot of certainty whether something must be false — either we will see it directly on our diagram, or we can accurately see that an answer absolutely must be false by thinking about how the rules come together.

In terms of what could be true, we can certainly use our understanding and our diagram to consider this issue, and we can be fairly accurate, but, say you missed an initial inference or didn’t see something that can’t work/must be false, then it would be very easy to think something could be true (when in fact it’s not), eliminate that answer, and move on without realizing you’ve made a mistake.

So, focusing on the right answer will, in this case, save you work, and, again, make it less likely that you will make an unnecessary mistake.

Now let’s imagine we’ve been given a “could be true” question.

In this case we know one answer (the right one) could be true, and four must be false.

If we go searching for a could be true answer, we could very well select one thinking that it could be true, when in fact it only looks that way because we failed to see an inference.

However, if we go into the answers with a mindset of eliminating what must be false, the worst thing that will happen, if you happened to have trouble seeing an inference or two, will be that you won’t be able to eliminate all wrong answers, and at that point you’ll have to consider the remaining choices more carefully.

So again, in this instance, working from what you know must be can prevent you from making unnecessary mistakes.

That’s it — gosh, this always seems simpler in my head than it does when I put it down on paper, and not sure if any of the above makes sense to anyone, but, if you were curious about the subject, I hope this sheds some light on it, and if you have any q’s just let me know —

Mike

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