L1 HW Logic Games

[lexigibbs]

I am extremely confused on these in the sense that the rules we are given at the beginning of the game, those remain in use through out every question of the entire game correct? On homework L1 page 1-105 #15,17,18 i get confused because I dont know whether the rules from the game go away when the question says assume like in number 18 or if the rules remain the same for the whole game? I can set up the games great but i get stumped when it starts switching the rules because I have no idea of the rules stay the same or not.

Thank you!

[Adam Tyson]

I understand your confusion, Lexi, and you are not alone. In general, the initial set of rules given in the scenario and rule set remain constant throughout the game - those are the "global" rules that govern the game. With some questions, you will get a new rule, usually introduced by the word "if", that applies to that question only, and that "local" rule works IN ADDITION TO the global rules, rather than supplanting them.

You may, for example, have a set of global rules that includes "X is not 4th". Then, in the course of the game, you encounter a question that asks "If X is after V but before T, which of the following could be true?" In attacking this question, you must follow both the global rule, that X cannot be 4th, and then layer on top of that the new restriction (that applies only to this question) that sets up a sequence of V-X-T. The local rule doesn't change the global rule, or remove it, but adds new specificity for one question.

Adding to that complexity, you may sometimes get a question that explicitly tells you to change a global rule. We call those either "rule substitution" or "rule suspension" questions, and historically they have been the last question of the game when they occur at all. Rule substitution tells you to take out an old global rule and put a new rule in its place - in my example, that might be something like "Suppose that the rule that says X is not 4th is replaced with the rule that X is no later than 4th". In that situation, you must consider the implications of not only the removal of the old rule and the introduction of this new rule, but also the impact such a change has on the inferences you made in the original setup.

Rule suspension is a little simpler, typically, and that's where they tell you to simply ignore one of the original rules. That might read something like "Suppose the restriction that X is not 4th is removed, but all the other rules remain in effect." Again, you must consider the impact on your diagram of the removal of that global rule, AND consider what that does to any inferences that you made based on that rule and on that rule's interaction with the other rules.

Overall, the global rules are constant - they apply to every question. Local rules like "If X is 3rd" apply only to that question and are in addition to, not in place of, the global rules. Rule substitution and rule suspension tend to be self-explanatory - they will tell you what changes to make, and what changes not to make, to the original rule set.

I hope that helps. Good luck in your continued studies!