Philosophy Now Forum

Speakpigeon wrote: ↑Fri Jan 25, 2019 12:40 pm

Logik wrote: ↑Thu Jan 24, 2019 12:01 pm Modus Tollens doesn't solve anything, numb nuts.
If the premise is true (P)
And the argument is valid (V)
Then the conclusion is true (C)
P ∧ V ⇒ C
Write out the truth-table, cretin.
P V C
0 0 0 If the premises are false AND the argument is invalid the conclusion is false
0 1 0 If the preises are false AND the argument is valid the conclusion is false.
1 0 0 If the premises are true AND the argument is invalid the conclusion is false.
1 1 1 If the premises are true AND the argument is valid the conclusion is true.

No.
This proves you don't even know the truth table of the material implication.
So, here is the correction of your "truth table" completed with the three missing logical cases in bold red:

P V C
0 0 0 If the premises are false AND the argument is invalid the conclusion is false
0 1 0 If the premises are false AND the argument is valid the conclusion is false.
1 0 0 If the premises are true AND the argument is invalid the conclusion is false.
0 0 1 If the premises are false AND the argument is invalid the conclusion is true.
0 1 1 If the premises are false AND the argument is valid the conclusion is true.
1 0 1 If the premises are true AND the argument is invalid the conclusion is true.
1 1 1 If the premises are true AND the argument is valid the conclusion is true.

You are an ignoramus. A loud and abusive ignoramus.
EB

Moron. What you have provided is not the truth-table for P ∧ V ⊢ C

A function with 2 inputs can not have 7 outputs! Not to mention that 7 is now power of 2 so you still missed one

You know. Because 2^2 = 4.

The irony. To call me an ignoramus when you fail basic arithmetic.

You don't even how to stay on the right side of the law of non-contradiction.

Speakpigeon wrote: ↑Fri Jan 25, 2019 12:40 pm 1 0 0 If the premises are true AND the argument is invalid the conclusion is false.
1 0 1 If the premises are true AND the argument is invalid the conclusion is true.

surreptitious57 wrote: ↑Thu Jan 24, 2019 1:38 pm

Speakpigeon wrote:
Could you give an example of a scientific theory you think is logically not valid

Science is inductive and so deals with what is probably true not what is definitely true

All irrelevant to my post.
I said "scientific theory", not science.

surreptitious57 wrote: ↑Thu Jan 24, 2019 1:38 pm New evidence could falsify every single one of them including the most rigorous ones

I didn't talk of the falsification of scientific theories. I asked for an example of a scientific theory you think is logically not valid.
I don't have the time to correct your numerous factual mistakes.
If you can't read properly or if you don't understand English, please, just ignore me.
EB

Logik wrote: ↑Fri Jan 25, 2019 12:50 pm
Moron. What you have provided is not the truth-table for P ∧ V ⊢ C.
A function with 2 inputs can not have 8 outputs!
You know. Because 2^2 = 4.
The irony. To call me an ignoramus when you fail basic arithmetic.

There are three logical variables, P, V and C, so 8 cases.
You should look up a textbook on the truth table of the material implication.
EB

Speakpigeon wrote: ↑Fri Jan 25, 2019 12:59 pm There are three logical variables, P, V and C, so 8 cases.

C is the ASSERTED from P and V.
P and V are the inputs.
C is the output.

P has 2 possible values.
V has 2 possible values.

The total number of permutations is 4.

If my abuse was to be in proportion to your stupidity then I am definitely not abusive enough!

Logik wrote: ↑Thu Jan 24, 2019 2:08 pm

Speakpigeon wrote: ↑Thu Jan 24, 2019 12:30 pm Look here what the Modus tollens really says: ¬B ∧ (A → B) ⊢ ¬A

(...)
So ¬B ∧ (A → B) ⊢ ¬A is exactly the same thing as ¬C ∧ V ⊢ ¬P

But that last line ins't what you claimed earlier.
You said "If ¬C ⇒ ¬P", not "¬C ∧ V ⊢ ¬P":

Logik wrote: ↑Thu Jan 24, 2019 12:01 pm Modus Tollens says If ¬C ⇒ ¬P. But that's incomplete!

See? You didn't mention "V" at all.
So, yes, your own definition of the "Modus tollens" is incomplete.
You would need to retrain starting from kindergarten.
EB

Speakpigeon wrote: ↑Fri Jan 25, 2019 1:10 pm

Logik wrote: ↑Thu Jan 24, 2019 2:08 pm

Speakpigeon wrote: ↑Thu Jan 24, 2019 12:30 pm Look here what the Modus tollens really says: ¬B ∧ (A → B) ⊢ ¬A

(...)
So ¬B ∧ (A → B) ⊢ ¬A is exactly the same thing as ¬C ∧ V ⊢ ¬P

But that last line ins't what you claimed earlier.
You said "If ¬C ⇒ ¬P", not "¬C ∧ V ⊢ ¬P":

Logik wrote: ↑Thu Jan 24, 2019 12:01 pm Modus Tollens says If ¬C ⇒ ¬P. But that's incomplete!

See? You didn't mention "V" at all.
So, yes, your own definition of the "Modus tollens" is incomplete.
You would need to retrain starting from kindergarten.
EB

Well. You are dumber than I thought.

Logik wrote: ↑Fri Jan 25, 2019 1:04 pm

Speakpigeon wrote: ↑Fri Jan 25, 2019 12:59 pm There are three logical variables, P, V and C, so 8 cases.

C is the ASSERTED from P and V.
P and V are the inputs.
C is the output.

There are no notion of input or of output for determining the truth table of a logical formula.
So, it's quite simple. You identify in the formula the logical variables, those that can be true or false, that's two possible cases for each variable, and so the number of possible cases overall will be 2 to the power of n, n being the number of logical variables you've identified. Three variables in your example, P, V and C, so 8 logical cases.
EB

Speakpigeon wrote: ↑Fri Jan 25, 2019 1:22 pm

Logik wrote: ↑Fri Jan 25, 2019 1:04 pm

Speakpigeon wrote: ↑Fri Jan 25, 2019 12:59 pm There are three logical variables, P, V and C, so 8 cases.

C is the ASSERTED from P and V.
P and V are the inputs.
C is the output.

There are no notion of input or of output for determining the truth table of a logical formula.
So, it's quite simple. You identify in the formula the logical variables, those that can be true or false, that's two possible cases for each variable, and so the number of possible cases overall will be 2 to the power of n, n being the number of logical variables you've identified. Three variables in your example, P, V and C, so 8 logical cases.
EB

Stop stealing out air!

The notion of input and output comes directly from the words IF ..... THEN...

Logik wrote: ↑Fri Jan 25, 2019 1:27 pm

Speakpigeon wrote: ↑Fri Jan 25, 2019 1:22 pm

Logik wrote: ↑Fri Jan 25, 2019 1:04 pm

C is the ASSERTED from P and V.
P and V are the inputs.
C is the output.

There are no notion of input or of output for determining the truth table of a logical formula.
So, it's quite simple. You identify in the formula the logical variables, those that can be true or false, that's two possible cases for each variable, and so the number of possible cases overall will be 2 to the power of n, n being the number of logical variables you've identified. Three variables in your example, P, V and C, so 8 logical cases.
EB

The notion of input and output comes directly from the words IF ..... THEN...

No notion of input/output in logic, ever.
You're an ignoramus and you make up nonsensical stuff as you go.
EB

Speakpigeon wrote: ↑Fri Jan 25, 2019 2:00 pm

Logik wrote: ↑Fri Jan 25, 2019 1:27 pm

Speakpigeon wrote: ↑Fri Jan 25, 2019 1:22 pm
There are no notion of input or of output for determining the truth table of a logical formula.
So, it's quite simple. You identify in the formula the logical variables, those that can be true or false, that's two possible cases for each variable, and so the number of possible cases overall will be 2 to the power of n, n being the number of logical variables you've identified. Three variables in your example, P, V and C, so 8 logical cases.
EB

The notion of input and output comes directly from the words IF ..... THEN...

No notion of input/output in logic, ever.
You're an ignoramus and you make up nonsensical stuff as you go.
EB

If the logic you are being taught has no inputs and outputs - ask for your money back!

Logik wrote: ↑Fri Jan 25, 2019 2:12 pm If the logic you are being taught has no inputs and outputs - ask for your money back!

That's all you can articulate?
Not exactly compelling.
Aristotle wouldn't have been impressed.
EB

Speakpigeon wrote: ↑Fri Jan 25, 2019 3:58 pm

Logik wrote: ↑Fri Jan 25, 2019 2:12 pm If the logic you are being taught has no inputs and outputs - ask for your money back!

That's all you can articulate?
Not exactly compelling.
Aristotle wouldn't have been impressed.
EB

Aristotle was an idiot.

Logik wrote: ↑Fri Jan 25, 2019 4:22 pm Aristotle was an idiot.

Very easy to say but impossible to argue as you declined to articulate your point.
EB

Speakpigeon wrote: ↑Fri Jan 25, 2019 5:34 pm

Logik wrote: ↑Fri Jan 25, 2019 4:22 pm Aristotle was an idiot.

Very easy to say but impossible to argue as you declined to articulate your point.
EB

Trivial to argue. Justify the law of excluded middle.

Logik wrote: ↑Fri Jan 25, 2019 6:20 pm

Speakpigeon wrote: ↑Fri Jan 25, 2019 5:34 pm

Logik wrote: ↑Fri Jan 25, 2019 4:22 pm Aristotle was an idiot.

Very easy to say but impossible to argue as you declined to articulate your point.
EB

Trivial to argue. Justify the law of excluded middle.

There's nothing to justify. The law of excluded middle, like all logical truths, is intuitive. You accept it or you don't, it's your problem.
Most people accept it, including all logicians since Aristotle, over a period of 2,400 years.
I put aside claims made in the context of modern mathematical logic and based on the notion of material implication as defined by a truth table, as it is inconsistent with our intuition of the logical implication.
If you think there is a problem with the law of excluded middle, it's up to you to articulate why it would be inconsistent.
If you don't, then there's no point going further.
So, you haven't justified your claim that Aristotle was an idiot.
EB