Conditional Reasoning when conditional indicators are absent

[moalkhaf]

Good afternoon. I am experiencing some difficulty with recognizing when conditional reasoning is present in a question when there are no conditional indicators present to signify that a conditional relationship exists. For example, while completing the Parallel Reasoning Question Problem Sets in the 2016 Logical Reasoning Bible, I ran into a bit of trouble completing question 4. This question is structured in the following manner: Bank deposits are credited on the date of the transaction only when they are made before 3.P.M. Alicia knows that the bank deposit was made before 3 P.M. So, Alicia knows that the bank deposit was credited on the date of the transaction.

I recognized that only when was a necessary indicator which allowed me to draw the first diagram and later the second diagram

BDC -----> B3P.M
B3P.M ------> BDC
I was incapable however of figuring out how to diagram the correct answer C. I would appreciate it if someone could clarify this diagram for me.

[Dave Killoran]

Hi Mo,

This is a tough question, so I'll refer you to the discussion of this question over at lsat/viewtopic.php?t=5742. Look in the middle of that thread for the comments from Emily, one of our LSAT instructors here. About B and C, she noted:

• "The mistaken reversal/sufficient-necessary flaw is one of the flaws in this question. The second flaw here is an assumption that Alicia KNOWS the information contained in the first sentence; if she doesn't, then there is no way for her to know the information in the third sentence. B and C both contain the sufficient-necessary mistake, but only C assumes with no basis that someone knows critical information (here, assumes George knows "George will be promoted to shift supervisor only if Helen resigns"). "

The diagram for (C) is:

• Premise: George will be promoted to shift supervisor Helen resigns ["only if" is your key term here!]
  Premise: George knows Helen will resign.
  
  Conclusion: George knows he will be promoted to shift supervisor

So, this answer not only has the same basic Reversal form as in the stimulus, but also the same "knowing" error as in the stimulus.

Getting this right requires a close reading of the question stem, which states: "Which one of the following exhibits both of the logical flaws exhibited by the argument above?" If you miss that "both," then it's easy to miss this question!

Thanks!