2 Questions

Matthew LLC

1. Can someone explain how the first and second sentences are rephrasings of each other?
- If the elevator malfunctioned, it wasn't properly maintained.
- The elevator would only have malfunctioned if it wasn't properly maintained.

2. What's the best way to tell the difference between a correct strengthen answer and a premise booster (or de-booster for weaken questions?) Had a little problem on PT62 Sec 4 #14

jdawg113

they are rephrasing because they say the same thing... the first one, if the elevator malfunctioned, it wasn't properly maintained that what it says. so you know if it was properly maintained then it didn't malfunction

the second is using only if... so if it was properly maintained then we know it didn't malfunction bc we are told it will malfunction ONLY IF it is not maintained properly so if it does malfunction we know it must not have been properly maintained, just break them down and see if you can understand what they are saying and figure out the possible worlds that the statement creates and you'll see here that the possibilities are the same (EM and was PM, was not PM and so there was no EM, or there was no EM but was not PM (EM-Elevator malfunction/PM-properly maintained))

jdawg113

Id have to look at the question to get a better idea of what you're asking but a good way to check ur AC for weaken/strengthen is negating the conclusion(or what is being weakened) and the AC and see if the opposite result takes place (TCR negated for weakening should strengthen a negated conclusion)

Matthew LLC

Ah, thanks. The second is using a form of "Only if." I kept trying to shift the if into the sufficient. I understand now.