Is there any truth to this statement?:
"Just because it is logical does not mean it's correct."
Define "logical."
>>1128126
False premises mean false conclusions even if the logic is sound
>>1128148
No.
Logic is necessarily valid. Sound premises imply that the premises are true. What you just said is a contradiction.
>>1128126
"Logos" mean 'word, speech, discourse'. A "logic" is a set of deductively valid rules and often times some metaphysical axioms (like the law of excluded middle).
A rule is valid if the conclusion necessarily follows from the premises. If the premises are true then the conclusion must follow.
Most logics are valid but unsound (their premises are false.)
There are many "logics." Intuitionistic logic, dialethism, dialetheism, classical logic and so on. There are also older ways to use "logic." Kant had a logical system which incorporated subject/object-relationships, which is very rare in contemporary analytic logics.
Formal logics developed as very pretentious syllogisms, which people have understood for a long time to be flawed. Formal logics are often based in classical logic but not exclusively so.
Logics don't mean anything if they aren't given a metaphysical, mathematical or scientific interpretation. Here they can be shown to be absurd or simply wrong.
If the world is indeterministic and the logic is deterministic, then the logic is unsound in how it depicts the physical system of the world.
That statement would be very true, as logic can merely test whether a set of propositions are consistent with themselves. It cannot test whether a proposition or a set of propositions is consistent with reality. An example would be this:
1. Johnny is a horse
2. All horses are pink
Therefore, Johnny is pink
>>1128169
>No.
>Logic is necessarily valid. Sound premises imply that the premises are true. What you just said is a contradiction.
Did you even read what I said?
> false premises + bad logic = false conclusion
> false premises + sound logic = false conclusion
> sound premises + bad logic = false conclusion
> sound premises + sound logic = sound conclusion
If something sounds logical but isn't correct, it just means at least one of the people involved around properly educated in the respective subject.
>>1128208
You're misusing the word 'sound'.
http://www.iep.utm.edu/val-snd/
>A deductive argument is sound if and only if it is both valid, and all of its premises are actually true.
'Sound logic' implies that the premises are true.
False premises + sound logic is a semantic contradiction.
What you mean is:
False premises + invalid logic does not necessitate truth.
False premises + valid logic does not necessitate truth.
True premises + invalid logic does not necessitate truth.
True premises + valid logic necessitates truth.
It sounds like you've never done any formal logic in your life.
Remember the truth definition of A=>B?
A implies B if every time A is true B is true.
But B could be true even if A is false.
B could be false even if A is false.
If it is not the case that (A=>B) you cannot claim that -A=>B. That is a propositional fallacy.
https://en.wikipedia.org/wiki/Denying_the_antecedent
>>1128244
Sorry.
If it is the case that A=>B and the case that -A you cannot imply -B.
This is what you're doing.
>>1128126
If a proposition is logically true, the by definition it must be true. That being said, a statement could be logically consistent in one possible world, yet not hold in the actual world.
Remove kebaba from the premises
>>1128126
if the logic doesn't claim certainty then obviously
ie. 51% of people are female therefore a randomly chosen person is probably female. and then it's not.
If you know A, and that A entails B, do you know B?
>>1128126
yes
Of course, that's exactly what a paradox is. You can do things that seem to follow the "rules" of logic but it doesn't matter in the end, what will be will be, no matter how you try and rationalize it
Life is a bit of a paradox if you think about it
>>1128126
Yes, when you argue with a woman.
Feelings > Logic in those times, and it's not always wrong.
>>1128169
Assuming you can account for all the relevant factors, which in the real world can number in the trillions.
So you usually can't.
>>1128861
The relevant factors are most likely uncountably infinite many, if we look at higher order logics. But even when we deal with infinitely many factors, we can make deterministic predictions.
There are 10^70 atoms in the universe. That is a lot more than trillions.
Physicists usually generalise it though. They see symmetries everywhere and greatly reduce the needed calculations. If half of the atoms act in the exact same way, we've removed 50% of the problem. Do this like 200 times and you've reduced the problem to calculable sizes.
Also, when physicists try to make super exact predictions usually look at close systems. They don't "truly" exist since they are always affected by outside gravity etc. But it is possible to reduce the outside influence to a minimum. These closed systems usually only have a small number of elements in them. In that case it is much less than trillions.
It is also important to remember that the indeterminacy of QM cannot be accounted with local hidden variables due to Bell's theorem.
However, despite all these nonsensical pragmatic concerns, the principle you're alluding to still hold true despite your additional assumption.
Have a logic which doesn't have colour in its ontology or account for it (like maths). I see colour. Therefore that logic isn't sound to apply to everything.
You're mom gets money from sex.
I had sex with you're mom.
Therefore I paid you're mom for the sex.
>>1129131
That doesn't follow and it is 'your'.
A->B.
B.
A.
https://en.wikipedia.org/wiki/Affirming_the_consequent
Are people on this board really this stupid or are everyone just trolling?
Seriously? Imagine a husband having sex with a hooker. Does he have to pay the hooker? No.
Think for like a second before posting.
>>1129147
your the only dumb here
>>1129147
lol whad a fag :DDD
>>1128169
I think what he is saying is you can perform legal logical operations on statements and get conclusions that are wrong because the statements are wrong
>>1128664
>fucking around with semantics
>logic
pick one
Even if you're correct, it doesn't mean you're right.
People don't die when they are killed.
>>1130932
that's not a flaw in the tool (logic) its a flaw in the user. A calculator isn't broken if I type in the wrong numbers.
>>1128126
If the logic is valid but the premises are false.
