# Falsity implies anything?!?!?

kennethamy

Fri 2 Oct, 2009 06:15 pm
@Emil,
Emil;94829 wrote:
:OK:

Kennethamy probably knows more logic than I do. I'm only 20.

Knowledge of logic is not a function of age. Frank P. Ramsey, who knew more logic than both of us put together, times 10, died at the age of 26.

Frank P. Ramsey - Wikipedia, the free encyclopedia

Emil

Fri 2 Oct, 2009 06:43 pm
@kennethamy,
kennethamy;94834 wrote:
Knowledge of logic is not a function of age. Frank P. Ramsey, who knew more logic than both of us put together, times 10, died at the age of 26.

Frank P. Ramsey - Wikipedia, the free encyclopedia

It's too bad that he died so early. Sounds like he could have contributed a lot more.

Fil Albuquerque

Sun 18 Oct, 2009 12:59 pm
@JeffD2,
A not B then AB ...

To negate, the proponents recognize each other presence, and assimilate...

Regards>FILIPE DE ALBUQUERQUE

kennethamy

Sun 18 Oct, 2009 01:04 pm
@Fil Albuquerque,
Fil. Albuquerque;98332 wrote:
A not B then AB ...

To negate, the proponents recognize each other presence, and assimilate...

Regards>FILIPE DE ALBUQUERQUE

Your answer to what? This is a question about formal logic, because it is in formal logic that a false proposition implies any proposition. So how can an answer not have anything to do with formal logic?

Fil Albuquerque

Sun 18 Oct, 2009 01:07 pm
@kennethamy,
kennethamy;98335 wrote:
Your answer to what? This is a question about formal logic, because it is in formal logic that a false proposition implies any proposition. So how can an answer not have anything to do with formal logic?

Sorry, I was referring to myself, i did not study Logic, so I am stating only an informal opinion...but I would like to know what you or someone else think of it.

Regards>FILIPE DE ALBUQUERQUE

kennethamy

Sun 18 Oct, 2009 01:11 pm
@Fil Albuquerque,
Fil. Albuquerque;98337 wrote:
Sorry, I was referring to myself, i did not study Logic, so I am stating only an informal opinion...but I would like to know what you or someone else think of it.

Regards>FILIPE DE ALBUQUERQUE

This is not a matter of opinion. It is a matter of formal logic.

Fil Albuquerque

Sun 18 Oct, 2009 01:12 pm
@kennethamy,
"Roger"...:surrender:

leafy

Mon 19 Oct, 2009 06:08 pm
@kennethamy,
kennethamy;98335 wrote:
Your answer to what? This is a question about formal logic, because it is in formal logic that a false proposition implies any proposition. So how can an answer not have anything to do with formal logic?

Doesn't that rely on Disjunctive Syllogism or Reductio Ad Absurdum?

kennethamy

Mon 19 Oct, 2009 06:12 pm
@leafy,
leafy;98632 wrote:
Doesn't that rely on Disjunctive Syllogism or Reductio Ad Absurdum?

Actually, I think it is just the converse. DS, and RAA rely on F>X. But is that what you are asking?

leafy

Mon 19 Oct, 2009 07:32 pm
@kennethamy,
kennethamy;98633 wrote:
Actually, I think it is just the converse. DS, and RAA rely on F>X. But is that what you are asking?

Typically, it goes like this:
Leafy wrote:

kennethamy

Mon 19 Oct, 2009 07:35 pm
@leafy,
leafy;98661 wrote:
Typically, it goes like this:

Sorry, I don't know what you are getting at. Could you be more explicit?

leafy

Mon 19 Oct, 2009 07:46 pm
@kennethamy,
kennethamy;98664 wrote:
Sorry, I don't know what you are getting at. Could you be more explicit?

kennethamy

Mon 19 Oct, 2009 07:51 pm
@leafy,
leafy;98668 wrote:

I guess I don't understand what you mean by "relies". Do you mean that F>X implies DS or RAA? How?

leafy

Mon 19 Oct, 2009 08:40 pm
@kennethamy,
kennethamy;98670 wrote:
I guess I don't understand what you mean by "relies". Do you mean that F>X implies DS or RAA? How?

I'm exploring your usage of it:

kennethamy;98633 wrote:
Actually, I think it is just the converse. DS, and RAA rely on F>X. But is that what you are asking?

Emil

Tue 20 Oct, 2009 12:28 am
@leafy,
leafy;98632 wrote:
Doesn't that rely on Disjunctive Syllogism or Reductio Ad Absurdum?

No it does not. Logical implication is defined in a way such that it directly follows from the definition. With the possible worlds' approach it is defined something like this:

[INDENT]P implies Q iff there is no possible world where it is not the case that Q and it is the case that P.

[/INDENT]Obviously if there is no possible world where P is the case, then there is no possible world where P is the case and Q is not the case.

kennethamy

Tue 20 Oct, 2009 06:10 am
@Emil,
Emil;98699 wrote:
No it does not. Logical implication is defined in a way such that it directly follows from the definition. With the possible worlds' approach it is defined something like this:
[INDENT]P implies Q iff there is no possible world where it is not the case that Q and it is the case that P.

[/INDENT]Obviously if there is no possible world where P is the case, then there is no possible world where P is the case and Q is not the case.

Right. And then the other lines on the truth-table have to conform with, TF F, including that a false proposition (materially) implies any proposition.

Emil

Tue 20 Oct, 2009 08:01 am
@kennethamy,
kennethamy;98723 wrote:
Right. And then the other lines on the truth-table have to conform with, TF F, including that a false proposition (materially) implies any proposition.

What do you mean? I don't understand the sentence about truth tables and TF F.

I agree that a false proposition logically implies any proposition. I also agree that a false proposition materially implies any proposition. This is logically implied by the former.

kennethamy

Tue 20 Oct, 2009 08:06 am
@Emil,
Emil;98747 wrote:
What do you mean? I don't understand the sentence about truth tables and TF F.

I agree that a false proposition logically implies any proposition. I also agree that a false proposition materially implies any proposition. This is logically implied by the former.

Where did I say that? Are you all right?

Emil

Tue 20 Oct, 2009 02:31 pm
@kennethamy,
kennethamy;98751 wrote:
Where did I say that? Are you all right?

Two posts up. You know. I quoted you.

kennethamy

Tue 20 Oct, 2009 02:44 pm
@Emil,
Emil;98846 wrote:
Two posts up. You know. I quoted you.

No idea..........