Question

I have a few logic questions that I am having difficult with and would be greatful for any insight...

#1
I need to know if this is a real or apparent argument.

A: I saw Bob with Mary last night.
B: You saw Frank, Bob's identical twin, with Marsha last night.

I'm thinking that this is a real arguement...

#2. Also, I need to know if these statements are consistent or inconsistent.
(A and B are two different people)

A: I think Ian is at the tea house.
B: You know very well that Ian is not at the tea house.

I'm thinking consistent...

#3. A. If Hal is happy then Sam is sad.
B. Hal is happy and Sam is sad

For these statments, I need to determine:
a. If A is true, is B necessarily true, false, or undetermined?
b. If B is true, is A necessarily true, false, or undetermined...
c. If A is false, is B necessarily false, true, or undetermined?
d. If B is false, is A necessarily flase, true, or undetermined?

Thanks!

Answer 1

#1 That is an apparent argument. The person does not state a reason as to why he is arguing a difference. We have no "proof".

#2. That would be inconsistent. Again, we have no proof that the disagreement is based on fact.

#3. Statement B is based on fact. Statement A would be an opinion.

Answer 2

#1
I'm having trouble understanding why you say it is not a real arguement. Person A is stating that he saw Bob and person B is saying that person A really saw Frank. How is it possible for the two statements to both be true and thus inconsistent?

#2. Can't person A THINK something but KNOW the opposite (as person B is saying he does) making the two statements consistent?

#3. I do not get your answer to question 3. I am needing to know if I assume that statement A is true, what can I know about statement B (that it's necessarily true, false, or undetermined), and etc. for questions b, c, and d.

I'm thinking the answer would be undetermined in each case. (If A is true, B is undetermined, etc.)

Answer 3

I agree with your answer that each would be undertermined for exactly the reason you stated.

#2...I do not believe that a person can think something that he knows is not true.

Regarding #1... how do you know that I did not see Bob with Mary last night? You can well be mistaken unless you were with me?