Philosophy Logic Problem Help

[Rick]

I'm not sure if this covered, but I've I have tried a lot of places and don't get help, answers, or no response at all. I'm hoping I can get help with the following problems? I haven't started them, because I don't know where to start

Natural Deduction Proof

1.

1 ~Y ⇒ ~L
2 W v ~Y
3 W ⇒ ~B
/ ~B v ~L

2.

1 ~U • (G = ~T)
2 (~U v D) ⇒ (W • ~R)
/ W • ~U

3.


1 (M ⇒ P) ⇒ ~P
2 H ⇒ P
3 M ⇒ H
/ ~H

 

[Rick]

Why were you given the problems then?

Required class in college for my major.

 

[stapel]

Required class in college for my major.

Did they not cover logic or proofs in your class before they assigned these exercises? If not, then we really can't help, since we cannot here provide the weeks of classroom instruction necessary to teach you the background material necessary to put you in a position to "know where to start". Sorry.

 

[HallsofIvy]

stapel isn't being "mean". We are happy to help but if you are taking a course where you were assigned something like this and really "don't know where to start", you need more help than we can give. Do you at least know what all these symbols mean? I recognise "v" as being "or" but I don't think "•" is standard. Is it "and"? Finally, you have not actually stated what is to be done. Are you to determine whether or not these arguments are valid?

 

[Deleted member 4993]

I'm not sure if this covered, but I've I have tried a lot of places and don't get help, answers, or no response at all. I'm hoping I can get help with the following problems? I haven't started them, because I don't know where to start

Natural Deduction Proof

1.

1 ~Y ⇒ ~L
2 W v ~Y
3 W ⇒ ~B
/ ~B v ~L

2.

1 ~U • (G = ~T)
2 (~U v D) ⇒ (W • ~R)
/ W • ~U

3.


1 (M ⇒ P) ⇒ ~P
2 H ⇒ P
3 M ⇒ H
/ ~H

Can you translate those "logical statements" into "English statements"?

Start from there....

 

[JeffM]

I'm not sure if this covered, but I've I have tried a lot of places and don't get help, answers, or no response at all. I'm hoping I can get help with the following problems? I haven't started them, because I don't know where to start

Natural Deduction Proof

1.

1 ~Y ⇒ ~L
2 W v ~Y
3 W ⇒ ~B
/ ~B v ~L

It is almost impossible to help with proofs because we do not know what axioms and prior theorems you are allowed to use. Moreover, you do not give us the introduction to these problems. I am guessing that numbered statements are presumed true and that the statement preceded by / is to be proved.

In addition to Subhotosh Khan's suggestion, I'll give you a hint. See whether as an axiom or a prior theorem you have something that looks like this:

\(\displaystyle \{A \implies B\} \implies \{A \implies B\ v\ C\}\)

Edit: Oh, and read Read Before Posting before you start a new thread.

 

[HallsofIvy]

I'm not sure if this covered, but I've I have tried a lot of places and don't get help, answers, or no response at all. I'm hoping I can get help with the following problems? I haven't started them, because I don't know where to start

Natural Deduction Proof

1.

1 ~Y ⇒ ~L
2 W v ~Y
3 W ⇒ ~B
/ ~B v ~L

It's been a while so here's an example for this one: From the second line either W is true or ~Y is true.
If ~Y is true, then the first line tells us that ~L is true. If W is true then the third line tells us tht ~B is true. In either case, we know either~B is true or ~L is true, the conclusion.