Principle Questions

diontret

Just want to clear up something about principle questions. If the principle says something like, " One ought not make promises, if one knows they cannot fulfill the promise. In the answer choices are we only looking for the answer choice that say ,"One ought not do," thus eliminating all answer choices that says, "One ought to do."

Please let me know if you understand what I mean, and can answer this question.

BinghamtonDave

No, the contrapostive is still fair game as far as answer choices go.
If knows cannot fulfill---->ought not to
Ought to----->does not know cannot fulfill (or more directly possibly "can fulfill")

Where your strategy pays dividends is when it is applied to the structure of the argument. Any answer choice that states "if one ought not to then...." is incorrect because "ought not to" is necessary in our original structure. Similarly, "ought to" in the necessary condition is for this same reason incorrect.

I hope this helps
David

diontret

Yes, thanks! This helps a lot actually. It took me a couple times to understand what you were saying, but now I get it. Basically I need to check them all, and not eliminate based solely on the necessary condition not matching up in the answer choices.

BinghamtonDave

It sounds complicated in the beginning, but there is a finite number of ways they can trick us. With practice, we can see through the tricks.
Lets say we are asked to spell out:
If A---->B
~B---->~A would be correct

~A--->~B would be incorrect
B---->A would be incorrect

These forms repeat on several different question types.