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Logical Limit

Riwaaz_Ras
Posts: 1,046
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7/8/2016 6:23:58 AM
Posted: 5 months ago
Should a logic be discarded if it results in something that contradicts it's very foundation, for example - an uncaused cause.
(This is not a goodbye message. I may or may not come back after ten years.)
Rational_Thinker9119
Posts: 9,054
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7/8/2016 1:09:31 PM
Posted: 5 months ago
At 7/8/2016 6:23:58 AM, Riwaaz_Ras wrote:
Should a logic be discarded if it results in something that contradicts it's very foundation, for example - an uncaused cause.

There is no logical problem with an uncaused cause in this context. That would be like saying that there is a logical problem with the idea of an uneaten eater, which of course is absurd (as I am uneaten, but eat), or an unhandcuffed handcuffer (which is pretty much every police officer).
Furyan5
Posts: 1,228
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7/8/2016 3:32:09 PM
Posted: 4 months ago
At 7/8/2016 1:09:31 PM, Rational_Thinker9119 wrote:
At 7/8/2016 6:23:58 AM, Riwaaz_Ras wrote:
Should a logic be discarded if it results in something that contradicts it's very foundation, for example - an uncaused cause.

There is no logical problem with an uncaused cause in this context. That would be like saying that there is a logical problem with the idea of an uneaten eater, which of course is absurd (as I am uneaten, but eat), or an unhandcuffed handcuffer (which is pretty much every police officer).

lol logic obviously isn't your strong suit. An uneaten eater is not he same as an uncaused cause. But i think Riwaaz meant something along the lines of an uncaused effect/result. Where every effect/result is caused.
keithprosser
Posts: 1,951
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7/8/2016 3:48:19 PM
Posted: 4 months ago
I'd guess the OP intended to open a debate about paradoxes. Basically, what we want from logic is that it lets us work out what is true and what isn't. Obvously a form of logic that can prove false things are true is not much use (except to theologians of course - they specialise in such logic).

I'm not talking about making mistakes or using deliberately tricky premises or part games - I'm talking about genuine flaws in the rules of logic. There is at least one paradox that seems to show that the plain sort of of logic we routinely rely on can prove false things are true without breaking any rules or making a mistake.

'If this sentence is true, 2+2=5'

If you do a little bit of thinking, that sentence must be true. But as it is true, then 2+2=5 (modus ponens), so we have proved a statement we know is false to be true. That is disasterous, because we followed the rules of logic but we still got the wrong answer. That means we can't trust the rules of ordinary logic like modus ponens and modus tollens. Note there is nothing special about 2+2=5 - you can substitute anything you like and 'prove' it using this method.

The paradox is that while 'Curry's paradox' as it is called seems to be genuine and not due to any blunder or oversight logic is still usable - or is it?

There is an article on Curry's paradox on Wikipedia for more.
Rational_Thinker9119
Posts: 9,054
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7/8/2016 4:01:55 PM
Posted: 4 months ago
At 7/8/2016 3:32:09 PM, Furyan5 wrote:
At 7/8/2016 1:09:31 PM, Rational_Thinker9119 wrote:
At 7/8/2016 6:23:58 AM, Riwaaz_Ras wrote:
Should a logic be discarded if it results in something that contradicts it's very foundation, for example - an uncaused cause.

There is no logical problem with an uncaused cause in this context. That would be like saying that there is a logical problem with the idea of an uneaten eater, which of course is absurd (as I am uneaten, but eat), or an unhandcuffed handcuffer (which is pretty much every police officer).

lol logic obviously isn't your strong suit.

Coming from someone who has a win ratio in the 30's, that's funny.

An uneaten eater is not he same as an uncaused cause.

No it's not the exact same thing, it was an analogy. And you say logic isn't my strong suit? Lol

But i think Riwaaz meant something along the lines of an uncaused effect/result. Where every effect/result is caused.

That's not what he said....But if the uncaused cause is uncaused then it isn't the case that everything is caused, only contingent things are caused.
keithprosser
Posts: 1,951
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7/9/2016 7:49:11 AM
Posted: 4 months ago
RR certainly picked a bad example, but the point he raised is interesting:

Should a logic be discarded if it results in something that contradicts it's very foundation?
skipsaweirdo
Posts: 1,864
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7/9/2016 9:19:01 AM
Posted: 4 months ago
At 7/8/2016 3:48:19 PM, keithprosser wrote:
I'd guess the OP intended to open a debate about paradoxes. Basically, what we want from logic is that it lets us work out what is true and what isn't. Obvously a form of logic that can prove false things are true is not much use (except to theologians of course - they specialise in such logic).
Since the op isn't a paradox I'm not sure why you went off on a paradox tangent. Atheists very often misconstrue the first premise to say "Everything has a cause," subsequently asking, "what caused God?" However, aside from the apparent caricature of the argument, there are several problems with this. First, if the intent is to attack the concept of God"s eternality, then an atheist is forced to accept one of the following: that the universe either came into being, uncaused, out of nothing, or that it is eternal. The former is logically absurd, since it violates one of the most basic axioms in metaphysics, which is ex nihilo, nihil fit ("out of nothing, nothing comes"); The latter espouses the very thing being attacked: namely, the concept of eternality (though it is also in conflict with the Second Law of Thermodynamics, and the great body of evidence in favor of the "Big Bang" theory).
I'm not talking about making mistakes or using deliberately tricky premises or part games - I'm talking about genuine flaws in the rules of logic. There is at least one paradox that seems to show that the plain sort of of logic we routinely rely on can prove false things are true without breaking any rules or making a mistake.

'If this sentence is true, 2+2=5'

If you do a little bit of thinking, that sentence must be true.
But as it is true, then 2+2=5 (modus ponens),
Modus ponens doesn't prove false things as true. By definition modus ponens and tollens is an inference of a truth from acknowledged truths. 2+2=5 isn't an acknowledged truth. I do however agree that an abstract claim, if this sentence is true , can lead to logic problems, if my statement is true. Lol
so we have proved a statement we know is false to be true. That is disasterous, because we followed the rules of logic but we still got the wrong answer. That means we can't trust the rules of ordinary logic like modus ponens and modus tollens. Note there is nothing special about 2+2=5 - you can substitute anything you like and 'prove' it using this method.
Self referential statements could be argued as circular reasoning.
The paradox is that while 'Curry's paradox' as it is called seems to be genuine and not due to any blunder or oversight logic is still usable - or is it?

There is an article on Curry's paradox on Wikipedia for more.
skipsaweirdo
Posts: 1,864
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7/9/2016 9:28:12 AM
Posted: 4 months ago
At 7/8/2016 6:23:58 AM, Riwaaz_Ras wrote:
Should a logic be discarded if it results in something that contradicts it's very foundation, for example - an uncaused cause.
Valid in !logic doesn't mean what it means when used as defined in English. It simp!y means an arguments form is correct, not that the argument proves something that is sound. Look up valid in the dictionary, sound is listed usually as a synonym.
In logic an argument can be valid, which is basically pointless and serves no explanatory value. An argument has to be sound in logic, which is synonymous with valid in English but doesn't equate to being considered "valid" in logic. That in itself is ridiculous. Logic doesn't seem to be logical so the time. Lol