Validity of a simple logical argument

Is the argument valid?

  • No

    Votes: 6 54.5%

  • Yes

    Votes: 5 45.5%

  • I don't know

    Votes: 0 0.0%

  • The argument doesn't make sense

    Votes: 0 0.0%
  • Total voters
    11
  • Poll closed .
Speakpigeon said:
OK, I think I can surmise that nobody knows here any justification given by mathematicians, logicians, philosophers etc. that the definition of validity you use here is correct.
Oh, well, such is life.
EB
Click to expand...
Here is the mainstream connection between the two.
Difference between logic and mathematics.
Logic are one of the building blocks of mathematics whereas mathematics is the building itself. Logic helps us in giving argument required for mathematical proofs. Logic is independent while mathematics depends on it.
Click to expand...
What is the difference between logic and mathematics? - Quora

https://www.quora.com/What-is-the-difference-between-logic-and-mathematics
 
Write4U said:
Here is the mainstream connection between the two.
What is the difference between logic and mathematics? - Quora

https://www.quora.com/What-is-the-difference-between-logic-and-mathematics
Click to expand...
Logic are one of the building blocks of mathematics whereas mathematics is the building itself. Logic helps us in giving argument required for mathematical proofs. Logic is independent while mathematics depends on it.​

Which is why university department of science used to be called (maybe still are in some cases) the department of Philosophy. ( if I am not mistaken)
 
Speakpigeon said:
All irrelevant.

You don't seem to understand even simple English sentences.

Read again?

OK, I think I can surmise that nobody knows here any justification given by mathematicians, logicians, philosophers etc. that the definition of validity you use here is correct.
EB
Click to expand...
I already replied to that question earlier. Not interested in repeating it all.......:)
 
Quantum Quack said:
Which is why university department of science used to be called (maybe still are in some cases) the department of Philosophy. ( if I am not mistaken)
Click to expand...
That's a holdover from the days of Newton, where science was referred to as "natural philosophy."
 
Speakpigeon said:
Is your definition justified?
Can't you produce any justification given by professional experts, like mathematicians, logicians, philosophers etc. that the definition of validity you use here is correct?
EB
Click to expand...
That's a "no" from you, then, I take it.
 
Ye gods.

I posted something way back about a valid argument, how it's valid if it has premises and a conclusion.
I say something like "if it has a valid conclusion", which is, on the face of it, not quite how it goes.

Valid arguments have conclusions which are true or false, not "perhaps true or false" but actually only true or only false.
So valid arguments present a conclusion which is true if the premises are satisfied, otherwise false.

A conclusion can't be "maybe true, or maybe false", and Speakpigeon admitted a while ago in responding to my mistake, that a conclusion is true if, something or other, although he didn't say the conclusion is false if, some other thing.

But that's all there is: true or false, there aren't any alternatives in a valid argument.

Moreover, if A, B, and C are either true or false statements, and if they can only be true or false, not indeterminate or something else unspecified, then IF A THEN B is a statement about the truth values of A and B; IF A THEN B OR C is also true when IF A THEN B is.

That looks a bit surprising, but all the THEN clause says is that B and C are independent of A, except that when A is true IF A THEN B can't be false. Logic, huh?

So "valid conclusion" should be "a conclusion which can be satisfied", meaning it is either true or false, not both or neither. The computer you're using has transistors in it, for transistors it's true that when they're switched on we can abstract their state to the logical value "true"; if we didn't there wouldn't be any electronic computers. Computers therefore represent valid arguments (theories, engineering, etc), about physics.
 
James R said:
That's a "no" from you, then, I take it.
Click to expand...
Not quite. I remain open to the possibility that there is one.
I looked for one, never could find one.
Plus, different mathematicians and logicians have openly admitted their solution isn't quite the thing.
But, yeah, I'd be very, very surprised if anyone produced anything like a convincing justification.
Still, you can try.
EB
 
Things Speakpigeon has posted in this thread:
Speakpigeon said:
Definition of validity: If an argument is valid, then if its premises are true, then its conclusion is true.

Conclusions are true or false, not valid or invalid.

Logic says that if there is a valid implication in the real world, then if the premises are true in the real world, then the conclusion is true in the real world.
Click to expand...

So it certainly looks like Speakpigeon understands the difference between true and false. True doesn't mean valid because a valid argument can be false, although he does seem to have trouble with that. Invalid conclusions? I think I can point to one or two made by . . . Speakpigeon.

He posts this little gem, for instance:
Speakpigeon said:
"IF A THEN B", as written, is not valid.
Click to expand...
 
Speakpigeon said:
Well, that should be interesting. So, go on, prove to me I'm wrong and that "IF A THEN B", as written, is valid.
Click to expand...
I don't need to prove it to you.

All it says is if A is true, then so is B. If A is true and B is false, then (if A then B) is false. (consistency)
If (not A) then (B or not B), is also valid.

So if (if A then B) then (if (not A) then (B or not B)), is valid.

Another way to say it is: ((not A) or B) implies (B or not B). (equivalence)

It says nothing about a real physical world, only that A and B can be true or false independently.
 
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