A valid argument is one that is only true within itself and so is not objectively trueHugh Nose wrote:
In order to be sound a deductive argument must be valid
A sound argument is one that is both true within itself and is also objectively true
A valid argument is one that is only true within itself and so is not objectively trueHugh Nose wrote:
In order to be sound a deductive argument must be valid
You really should take another look at some of the things you have said here. Some are just plain false!Logik wrote: ↑Thu Jan 10, 2019 11:26 am The logical form of "Either nothing exists or God exists." is A ⊻ B ( https://en.wikipedia.org/wiki/Exclusive_or )
The truth table for XOR is as follows:
A | B | A⊻B
0 ⊻ 0 ⇒ 0
1 ⊻ 0 ⇒ 1
0 ⊻ 1 ⇒ 1
1 ⊻ 1 ⇒ 0
You insist (a priori) that A⊻B is true so you are discarding two possibilities (50% of the decision-space) without justifying why:
0⊻0 ⇒ 0 (Nothing exists and God doesn't exist)
1⊻1 ⇒ 0 (Something exists and God exists)
By inexplicably discarding the other possibilities you have left us with:
A | B | A⊻B
1 ⊻ 0 ⇒ 1
0 ⊻ 1 ⇒ 1
This, in turn can be reduced to A ⇔ ¬B which is the same form as A ⇔ ¬A. The law of excluded middle.
It's a truism.
Either there is a falsity you can point out, or you are a liar.
Don't do that. All introductions to logic teach Aristotelian (classical) logic. It's broken because the law of excluded middle is a mistake.
You are correct. I made an error. A ⇔ ¬A is not the law of excluded middle.
"A ⇔ ¬B is the same as A ∧ B" is False!You are correct. I made an error. A ⇔ ¬A is not the law of excluded middle.
A | B | A⊻B
1 ⊻ 0 ⇒ 1
0 ⊻ 1 ⇒ 1
A ⇔ ¬B is the same as A ∧ B ⇒ 1.
Which is the same as A ∧ ¬A ⇒ 1.
That is the law of excluded middle.
So, you fail the nitpicker test.
Many contemporary college "intro to logic" texts do offer a section on Aristotelian logic, but the primary focus in courses in introductory logic at the college level is introduction of the propositional calculus and the predicate calculus. Go to any of the contemporary publishers of logic texts for higher education and see for yourself.Hugh Nose wrote: ↑Thu Jan 10, 2019 7:30 am
Don't believe Logik and don't believe me... just check any decent site on the web that discusses propositional logic or check any introductory logic text.
Don't do that. All introductions to logic teach Aristotelian (classical) logic. It's broken because the law of excluded middle is a mistake.
Only because I was using ∧ in the way that I thought you were using it, as "or", and that was my error. Nevertheless, if we use the "and" understanding for ∧, it is still the case that,
I inverted them. Intentionally to see how far your nitpicking goes.
And had you interpreted the AND as OR you still made an error.
Those other two arguments weren't from me, you seem to have a habit of stripping the name of the person you quote for some reason. I can see why you think they are valid, but I'm afraid you are still confusing grammatical formations with logical ones. I'm going to try a different tack to see if we can get this explained for you.Hugh Nose wrote: ↑Wed Jan 09, 2019 3:42 pmPoint 1: All three of the arguments, argument P, and the two arguments you have offered are valid, but I can see why you might think they aren't.FlashDangerpants wrote: ↑Mon Jan 07, 2019 11:47 pmIt makes no difference, they aren't valid for the same reason your argument isn't. I'm pretty sure that is his point. I really don't understand why you can't see the problem, it's been made clear enough for you.Hugh Nose wrote: ↑Mon Jan 07, 2019 3:49 pm In order to know that one or the other, or both, are sound arguments, I would have to know if the first premise of each argument is true. In order to know that one or the other is not a sound argument, I would have to know that the first premise, or the second premise is false. If I don't know whether or not eh first premise is true or false, then I don't know if the arguments are sound arguments or not.
You just have to look at the OR part in the first premise and anyone unburdened by severe head wounds can see that it doesn't work.
You used the grammatical form of a disjunctive syllogism, but you got it totally wrong, it isn't a syllogism at all. Please stop being silly.
I am glad that you brought this last sentence up. i, an audience participant, have decided that;Hugh Nose wrote: ↑Thu Jan 10, 2019 10:57 amThe first time you posted this message, you said that the argument was invalid. I assume you have backed away from that claim. Perhaps you went back and re-read the excerpt from IEPLogik wrote: ↑Thu Jan 10, 2019 10:24 amEither Logik is a resident of New York, or Logik is a redisent of London.
Logik is not a resident of London.
Therefore Logik is a resident of New York.
The conclusion is false. How can I tell? Because I don't live in either of those cities. So..
The conclusion is false. How is that possible?A deductive argument is said to be valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false. Otherwise, a deductive argument is said to be invalid.
The explanation is that the premises are false.
Because I don't live in New York or London!
It is important to stress that the premises of an argument do not have actually to be true in order for the argument to be valid.You can call it a false dichotomy if you like, but the mere fact that it is a disjunction that does not mention all of the possibilities is not what makes it false. What makes it false is the fact that you don't live in New York or London. The statement, "Either Hugh Nose lives in Delaware or Hugh Nose lives in Pennsylvania" is as much a false dichotomy as "Either Logik is a resident of New York, or Logik is a redisent of London", yet it is true- I do in fact live in Pennsylvania.The premise is a false dichotomy.
One of us does indeed need instruction and one of us does indeed need to read more carefully. The audience can decide who.
Cheers,
Hugh
You say,Logik wrote: ↑Thu Jan 10, 2019 2:24 pm Then you should stop teaching people bullshit.
According to your argument the truth-table for "Either nothing exists or God exists" is as follows:
A B
1 0 True
0 1 True
Follows: A ⇔ ¬B (1)
LEM states: A ∨ -A ⇒ True
From (1) replacing A with ¬B into LEM follows: ¬B ∨ -A ⇒ True
Either God doesn't exist is true, or the negation of “nothing exists” is true.
Oops! Where do you stand on double negation?
If you are going to appeal to "Higher Education" perhaps you should consider High-order logics.
https://en.wikipedia.org/wiki/Higher-order_logic