Derivations and Subderivations

Multiple Choice: Click on the correct answer and the page will jump forward to the next problem.

1. If your goal is to derive 'J', then (because it has no main connective) all you can do to begin the derivation is assume 'J'.

a. True b. False

2. Once a subderivation is terminated,
each line is inacessible. (That is to say, each line is off limits and cannot
be cited.)

a.
True b.
False

3. If your goal sentence is of the form
'P>Q', then

a.
You will always use >I to derive it. b.
You will often use >I to derive it. c.
You will always use >E to derive it. d.
You will often use >E to derive it.

4. If your goal sentence is of the form
'P=Q', then you
may need to derive this by using =I *in the end*. But in order to do this
one should first...

a.
try to prepare for =I by first deriving two conditionals. This may require two
applications of >I. b.
try to prepare for =I by first using ~I to prove ~(P=Q).
c.
try to prepare for =I by assuming P=Q.