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Diagramming Help: Powerscore method vs. mine?

Posted: Sun Jun 19, 2011 7:02 pm
by norcal123456
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Re: Diagramming Help: Powerscore method vs. mine?

Posted: Sun Jun 19, 2011 10:03 pm
by youknowryan
norcal123456 wrote:How would you diagram:

Drivers with a large number of demerit points who additionally have been convicted of a serious driving-related offense should either be sentenced to jail or be forced to receive driver reeducation, since to do otherwise would be to allow a crime to go unpunished. Only if such drivers are likely to be made more responsible drivers should driver reeducation be recommended for them. Unfortunately, it is always almost impossible to make drivers with a large number of demerit points more responsible drivers.

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Powerscore suggests you to diagram with subscripts using the "either/or formula" as follows:

SJ=sentenced to jail
RE=receive driver reeducation
MR=made more responsible

SJ -> RE
RE -> MR
MR
RE
So: SJ

My question is... would it also be correct to diagram the first sentence "either/or" part like this?

DP=demerit points
SO=convicted of serious offenses
SJ=sentenced to jail
RE=receive driver reeducation
MR=made more responsible

DP & SO -> SJ or RE
RE -> MR
MR
RE

The correct answer was just a repeat form of "Drivers with a large number of demerit points who have been convicted of a serious driving-related offense should be sent to jail", but I just wanted to know if my method of diagramming was the "correct" or "proper" logic way to go about the first sentence containing either/or.

Thanks in advance!!
DO NOT diagram this problem. Read it and understand what the author is driving at... when you do, only one answer is even close to right.

Re: Diagramming Help: Powerscore method vs. mine?

Posted: Sun Jun 19, 2011 11:22 pm
by suspicious android
DP & SO -> SJ or RE
RE -> MR
~MR
~RE
[modified slightly to preserve negations]
It's fine. Like the other poster pointed out, this is probably a problem you would not want to be diagramming on test day, but to get really comfortable with conditional reasoning, it's often helpful to do a little bit of overkill. Your version of the diagramming preserves some additional aspects of the stimulus compared with the version in the book. This is sometimes helpful and sometimes confusing, you'll learn as you go when you want to simplify and when you don't (you'll usually want to simplify). Your version allows you to infer:

DP & SO --> SJ

Which is a good match with the correct answer. As is shown in another thread going on, there is rarely one correct way to diagram sentences in symbolic logic. It's more of an art than a science. Now, it's a profoundly boring art, but still...