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**Studying for the LSAT / Powerscore Logic games Bible Not-Law question**

« **on:**June 06, 2009, 04:04:07 PM »

There is a "strategy" in Powerscore's Logic games bible that I'm not sure is really sound; it concerns the diagramming of uncertain relationships.

For instance, it says that if you are told only that 2 items, say P and Q, must occur before another, let's say R, in a 6 day week, then you would diagram something like the following:

....-.........- - - - -

~R ~R (~P,~Q)

(periods inserted to simulate the diagram as it would appear in your own notes...just imagine they aren't there)

I have doubts as to whether it is wise to so quickly eliminate R from possibly occurring second in the sequence. First of all, the Logic games Bible states that since we are not told what the relationship between P and Q are, we only know that it may be that P occurs before Q, Q occurs before P, or they occur concurrently. But if we can't rule out that last possibility of P and Q occurring at the same time, then how can we presumptively cross out R underneath the second slot? That presumes that P and Q cannot occur at the same time, and so that R cannot occur second in the sequence.

Furthermore, the logic in their notation for these first two slots and the last slot seems inconsistent. In the last slot, the possibility of P and Q's occurring simultaneously is taken account of--the 5th slot doesn't eliminate P and Q from possibly happening together, and so notes correctly that R might occur last. Otherwise the author would have indicated that because P and Q might occur separately, if R occurs right after either P or Q, then there is a chance that because one of the disjuncts (i.e., P, Q) might "bump" R out of the last slot, then ~P and ~Q should likewise be indicated below the 5th slot.

If anyone can shed some light on this, I'd be really grateful.

TSW

p.s. following the tradition of philosophical logic, I have represented all 'nots' in my "diagram" with the tilde (~) symbol.

p.p.s. if you want to follow along in your copy of the Bible, I have the Webcom edition, and it's on pgs 17-18. Or you can view scans of these problems here: http://picasaweb.google.com/changesmyweltanschauung/Powerscore#5344435170144698690

For instance, it says that if you are told only that 2 items, say P and Q, must occur before another, let's say R, in a 6 day week, then you would diagram something like the following:

....-.........- - - - -

~R ~R (~P,~Q)

(periods inserted to simulate the diagram as it would appear in your own notes...just imagine they aren't there)

I have doubts as to whether it is wise to so quickly eliminate R from possibly occurring second in the sequence. First of all, the Logic games Bible states that since we are not told what the relationship between P and Q are, we only know that it may be that P occurs before Q, Q occurs before P, or they occur concurrently. But if we can't rule out that last possibility of P and Q occurring at the same time, then how can we presumptively cross out R underneath the second slot? That presumes that P and Q cannot occur at the same time, and so that R cannot occur second in the sequence.

Furthermore, the logic in their notation for these first two slots and the last slot seems inconsistent. In the last slot, the possibility of P and Q's occurring simultaneously is taken account of--the 5th slot doesn't eliminate P and Q from possibly happening together, and so notes correctly that R might occur last. Otherwise the author would have indicated that because P and Q might occur separately, if R occurs right after either P or Q, then there is a chance that because one of the disjuncts (i.e., P, Q) might "bump" R out of the last slot, then ~P and ~Q should likewise be indicated below the 5th slot.

If anyone can shed some light on this, I'd be really grateful.

TSW

p.s. following the tradition of philosophical logic, I have represented all 'nots' in my "diagram" with the tilde (~) symbol.

p.p.s. if you want to follow along in your copy of the Bible, I have the Webcom edition, and it's on pgs 17-18. Or you can view scans of these problems here: http://picasaweb.google.com/changesmyweltanschauung/Powerscore#5344435170144698690