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# Logic should not be trusted.

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Luminar Posted: Thu, Jun 28 2012 6:58 AM

There is no reason to believe logic since the justifications for logic are based on the validity of logic and are therefore circular. For instance, the validity of Occam's Razor (being based on fact that the more assumptions one makes the more likely one is to be wrong) is dependent upon Occam's Razor itself, since without it we would have no way of estimating the probability of Occam's Razor being based upon some unknown flaw in our minds. And without such an anchor, our entire perception of logic collapses. Here is a summary:

1. Occam's Razor could be false.
2. Our justification of Occam's Razor is dependent upon Occam's Razor.
3. Therefore we have no way of measuring the validity of Occam's Razor.
4. Without Occam's Razor logic collapses.
5. Therefore logic should not be trusted.

Some have accused this argument of being circular; seeing as I am using logic to invalidate itself. To understand this more clearly, let us examine my assertion:

"No logic should be trusted."

You'll notice that it doesn't say that all logic is necessarily false, only that it has a reasonable chance of it. There are two possibilities here:

1. Not all logic is valid, but some of it is, specifically the types I am using to refute logic. This is suggested by the fact that logic disproves it's own validity. Note I do not concede that logic should not be trusted since we would still be unaware of the extent of each type of logic's validity (certain axioms of the same type of logic might contradict each other).

2. Logic is totally wrong, which would invalidate my argument. But because my argument has nothing to do with all logic being objectively false, I have nothing to fear from this.

Also, I will preemptively respond to those who will use the trust argument and claim that having only ever experienced the reliability and consistency of axioms gives them good epistemic reasons for believing that they are, in fact, accurate representations of reality.

This argument is presupposed upon the validity of logic itself and is therefore circular. My point is that we had no way of measuring how likely anything is, since Occam's Razor was our measurement of probability. Who is to say that whatever you have experienced gives you reasons for assuming it is true? It could be logical for patterns to fit your perception of reality until a certain date, say December twenty-first 2012, then collapse. It could be logical that nothing exists, even you (from your standpoint).

Who is to say that you have experienced anything at all? Since there is no means of determining probability (such as Occam's Razor), who is to say that your memories from before the present moment have likely not been artificially created in an instant, and that you will cease to exist in the next? Even if you are what you percieve yourself to be, you have no way of knowing if a moment was real anytime that moment becomes the past. At this point I'm just rambling on about the possibilities.

Anyway, what do you think? Is this a good enough argument?

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Torsten replied on Thu, Jun 28 2012 7:18 AM

No replies and already five stars? Hehe, it wasn't me, but I like the subject.

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excel replied on Thu, Jun 28 2012 7:43 AM

Does this assertion also apply to math and geometry?

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MaikU replied on Thu, Jun 28 2012 7:48 AM

Yeah, logic sucks. I'm ok with empirical evidence and science though. Still no God...

"Dude... Roderick Long is the most anarchisty anarchist that has ever anarchisted!" - Evilsceptic

(english is not my native language, sorry for grammar.)

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Torsten replied on Thu, Jun 28 2012 8:07 AM

I'm ok with empirical evidence and science though

You can't use empirical evidence without logic and for sure you can not do good science with a sound logic.

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mikachusetts replied on Thu, Jun 28 2012 8:07 AM

Without Occam's Razor logic collapses.

This is simply untrue, Occam's Razor isn't even part of formal logic.

The charge of circularity has some merit, because the law of non-contradiction has to assumed as true in any attempt to disprove it.  But its not a vicious circularity so it doesn't actually pose a problem.  Its not the same thing as assuming the conclusion in the premise.

they said we would have an unfair fun advantage

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Wheylous replied on Thu, Jun 28 2012 10:04 AM

I don't usually bother to reply to pointless threads, but I have the feeling you don't know much about OR.

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Aristophanes replied on Thu, Jun 28 2012 10:10 AM

If A, then C.

Therefore, C if A and B.

A -> C

(A^B) -> C

Can someone proof this?

Also, my guess is that the OP has never actually dealt in logic.

1. Occam's Razor could be false.
2. Our justification of Occam's Razor is dependent upon Occam's Razor.
3. Therefore we have no way of measuring the validity of Occam's Razor.
4. Without Occam's Razor logic collapses.
5. Therefore logic should not be trusted.

This is such a wildly complex set of premises.  I'd like to see the proof of it as well.

"The Fed does not make predictions. It makes forecasts..." - Mustang19
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Phi est aureum replied on Thu, Jun 28 2012 10:16 AM

This argument would have to apply to mathematics, and all that follow from it, such as geometry, mechanics, physics, nearly all science, etc.

It is an intriguing inquiry. It is essentially just questioning the premise, ie "Assume logic holds."

It is no different than the mathematical assumption that 0+1=1. Without that assumption, no mathematics (or what we currently call mathematics) could follow. Which is funny, because logic systems are based on 0s and 1s.

The only one worth following is the one who leads... not the one who pulls; for it is not the direction that condemns the puller, it is the rope that he holds.

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Autolykos replied on Thu, Jun 28 2012 10:38 AM

Refuting logic requires assuming the validity of logic. Oops...

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Serpentis-Lucis replied on Thu, Jun 28 2012 10:51 AM

Premise 4 of your argument requires a proof of it's own. You haven't proved that Occam's Razor is essential to the validity of logic. Not only that but any attempt at trying to prove that the validity of logic is dependent on Occam's Razor would likely be futile, logic has been around longer than Occam's Razor.

Edit to Add: Circularity is only a major problem when it comes to foundationalist epistemology. For your argument to be valid you would first need to argue that Foundationalism is the only valid epistemological position.

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shackleford replied on Thu, Jun 28 2012 3:22 PM

Occam's Razor is not a law of logic, theorem, or anything like that.

http://thephoenixsaga.com/
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MrSchnapps replied on Thu, Jun 28 2012 3:48 PM

Are you seriously serious right nao bro?

“Remove justice,” St. Augustine asks, “and what are kingdoms but gangs of criminals on a large scale? What are criminal gangs but petty kingdoms?”
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shackleford replied on Thu, Jun 28 2012 4:49 PM

MrSchnapps:

Are you seriously serious right nao bro?

Who are you talking to?

http://thephoenixsaga.com/
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MrSchnapps replied on Thu, Jun 28 2012 5:37 PM

OP. On second thought, if the OP really is 15 years old, then props.

However, a little philosophy is a dangerous thing. I suggest that you go read more--much more in the philosophy of logic.

“Remove justice,” St. Augustine asks, “and what are kingdoms but gangs of criminals on a large scale? What are criminal gangs but petty kingdoms?”
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Autolykos replied on Thu, Jun 28 2012 5:51 PM

What MrSchnapps just said. I recommend starting with the laws of thought.

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hashem replied on Thu, Jun 28 2012 9:43 PM

A thread that uses logic to argue against trusting logic. Wow...

Whenever you find yourself on the side of the majority, it's time to pause and reflect. —Mark Twain
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Luminar replied on Thu, Jun 28 2012 10:44 PM

I already addressed the issue of my argument being based upon logic in my opening post. I am not arguing that all logic is wrong, just that we have no way of knowing the likelihood of it being wrong. Also, Occam's Razor is a principle based on statics. The more assumptions one makes, the more likely one is to be wrong. It is clearly grounded in logic, and if it could not be trusted, it would mean that we would not be able to trust probability; hence anything could be possible.

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Andrew Cain replied on Thu, Jun 28 2012 10:48 PM

I think you are confusing human fallibility with logic.

'Men do not change, they unmask themselves' - Germaine de Stael

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Luminar replied on Thu, Jun 28 2012 10:53 PM

How would you differentiate between objective logic or our perception of it?

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Andrew Cain replied on Thu, Jun 28 2012 10:58 PM

The same way you did.

Objective logic and Human perceptions.

See, differentiated.

'Men do not change, they unmask themselves' - Germaine de Stael

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Luminar replied on Thu, Jun 28 2012 11:10 PM

U trollin bro? I'm obviously not referring to the concepts or definitions.

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Autolykos replied on Fri, Jun 29 2012 9:43 AM

If you're not referring to concepts or definitions, then what are you referring to?

You haven't escaped the performative contradiction in any way whatsoever.

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Seraiah replied on Fri, Jun 29 2012 10:47 AM

(These forums eating my posts is really starting to piss me off.)

Logic isn't trusted. This isn't news to Science, as the entire purpose of experimentation is to find out if the assumptions on which the logic is built are correct.

Irrational Numbers, the fact that light cannot collide with itself, the quantum erasure experiement, and the weak force/strong force all fly in the face of logic.

"...Bitcoin [may] already [be] the world's premiere currency, if we take ratio of exchange to commodity value as a measure of success ... because the better that ratio the more valuable purely as money that thing must be" -Anenome
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Autolykos replied on Fri, Jun 29 2012 10:58 AM

How so?

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MrSchnapps replied on Fri, Jun 29 2012 11:03 AM

Saying that science can disprove logic is like saying science can find a four-sided triangle. Once you understand what logic is, you'll see that it's absolutely nonsensical and ridiculous to say that quantum mechanics can 'disprove it' or radically modify our conception of it.

Science can't prove or disprove logic and mathematics. That is far outside its domain. It has to presuppose them to even get off the ground.

Put down the pop science books/Scientific American.

“Remove justice,” St. Augustine asks, “and what are kingdoms but gangs of criminals on a large scale? What are criminal gangs but petty kingdoms?”
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Autolykos replied on Fri, Jun 29 2012 11:08 AM

MrSchnapps:
Saying that science can disprove logic is like saying science can find a four-sided triangle. Once you understand what logic is, you'll see that it's absolutely nonsensical and ridiculous to say that quantum mechanics can 'disprove it' or radically modify our conception of it.

Science can't prove or disprove logic and mathematics. That is far outside its domain. It has to presuppose them to even get off the ground.

QFT

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Non parit potestas ipsius auctoritatem.

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Torsten replied on Fri, Jun 29 2012 11:45 AM

I smell some postmodernism. OK, I admit there are presuppositions people work with and that clean cut Logic and the inferenced logic and human minds can be and usually are two different things. So perhaps the initial author meant that our own human logic shouldn't be trusted (as opposed to an abstract perfect logic).

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Seraiah replied on Fri, Jun 29 2012 11:49 AM

MrSchnapps:
Science can't prove or disprove logic and mathematics.

I didn't say science disproves logic. I'm saying science doesn't trust logic because the outworkings of logic can result in incorrect results when the underlying assumptions are incorrect. (Which often happens.)

The entire purpose of experimentation is to ensure that the hypothesis (Even if it's a perfectly logical hypothesis) is correct. That's not an incidental effect of experimentation, that is, again, the entire purpose. It is not news to science that logic can't be trusted.

I said that quantum mechanics "flies in the face of logic", but I meant it flew in the face of logic before the underlying assumptions were adjusted.

Bad word choice on my part, but I think in context what I meant was clear, and accurate.

"...Bitcoin [may] already [be] the world's premiere currency, if we take ratio of exchange to commodity value as a measure of success ... because the better that ratio the more valuable purely as money that thing must be" -Anenome
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Buzz Killington replied on Fri, Jun 29 2012 11:51 AM

Interesting logic.

;)

"Nutty as squirrel shit."
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gotlucky replied on Fri, Jun 29 2012 12:24 PM

Seraiah:

I'm saying science doesn't trust logic because the outworkings of logic can result in incorrect results when the underlying assumptions are incorrect. (Which often happens.)

We have certain terms that we use in logic.  "Outworkings" are known as "conclusions".  If someone has a false conclusion, then either their premises are flawed or their argument is invalid.  That's all.  It's not that we can't trust logic, it's that people are imperfect.

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MaikU replied on Fri, Jun 29 2012 1:26 PM

no, refuting logic only requires some empirical evidence, that would show something completely paradoxical in our universe, some phenomena I mean.

"Dude... Roderick Long is the most anarchisty anarchist that has ever anarchisted!" - Evilsceptic

(english is not my native language, sorry for grammar.)

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Seraiah replied on Fri, Jun 29 2012 2:20 PM

gotlucky:
It's not that we can't trust logic, it's that people are imperfect.

You make the destinction between logic and the premises as if they're destinctly separate things, but I'm not so sure that's true.

One cannot separate Logic from premises and still be left with anything rational.

Take this example:

A is B
C is B
Therefore
A is C

This is only true because it has always been true in testable, repeatable, observations.

You're objection should be "We cannot possibly concieve of a universe in which that conclusion is not true." and that is entirely the point. Logic is instrinsic to the way we percieve reality; it can not be abstracted away from assumptions (premises).

Premise: A is B
Premise: C is B
Logic: Therefore
Conclusion: A is C

Logic cannot be trusted because it will always rely on premises that may not be correct.

This:

Premise: A is B
Premise: C is B

Logic: Therefore
Conclusion: A is C

Makes no sense.

Premise: Logic requires accurate premises to draw a correct conclusion.
Premise: There is no way to know for certain that the premise is correct, or that all variables are accounted for.
Premise: People shouldn't trust something that isn't always reliable.
Logic: Therefore
Conclusion: People should not trust logic.

You could say, "Well your premises could be wrong, so we shouldn't trust your logic either!" Ya, what's your point?

"...Bitcoin [may] already [be] the world's premiere currency, if we take ratio of exchange to commodity value as a measure of success ... because the better that ratio the more valuable purely as money that thing must be" -Anenome
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gotlucky replied on Fri, Jun 29 2012 2:34 PM

Seraiah,

There are different kinds of logical reasoning.  Usually, people refer to logic as deductive logic, but it is not always the case.  Anyway, deductive logic is about deriving conclusions from a set of premises.  It is about what logically follows.  Conclusions either follow or do not follow from any given set of premises.  Just because a set of premises may be false or incomplete does not mean logic cannot be trusted.  All it means is that one or more of the premises are false or that there are not enough premises to derive the conclusion.

In other words, arguments can be understood like this: Given this set of premises, this is the conclusion.

Now, whether or not those premises are true is an entirely different story.  But that has nothing to do with the argument itself.  You might also find The Relativity of Wrong by Isaac Asimov interesting.

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gotlucky replied on Fri, Jun 29 2012 2:38 PM

Seraiah:

Premise: Logic requires accurate premises to draw a correct conclusion.
Premise: There is no way to know for certain that the premise is correct, or that all variables are accounted for.
Premise: People shouldn't trust something that isn't always reliable.
Logic: Therefore
Conclusion: People should not trust logic.

You could say, "Well your logic could be wrong, so we shouldn't trust that either!" Ya, what's your point? Which premise does that knock against?

Your first premise is false.  Arguments require true and complete premises to draw true conclusions.  Do not mistake logic for the argument itself.

Your second premise is irrelevant.  Logic is not about truth.  Logic is the method of reasoning.  Certain disciplines use different kinds of logical reasoning in order to find truth.  But logic is a tool, it is not a purpose.

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Torsten replied on Fri, Jun 29 2012 2:55 PM

If someone has a false conclusion, then either their premises are flawed or their argument is invalid.

Or he's making a false inference. You can test for formal/informal fallacies. But sometimes there are problems that are only difficult to detect.

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gotlucky replied on Fri, Jun 29 2012 3:00 PM

Torsten:

Or he's making a false inference. You can test for formal/informal fallacies. But sometimes there are problems that are only difficult to detect.

A false inference is a false conclusion, which can only result from a set of premises that has at least one false premise or is an incomplete set of premises, or the argument is invalid.

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Torsten replied on Fri, Jun 29 2012 3:11 PM

No, one can make false conclusions, while all stated premises are correct. People are just more difficult to convince that something is wrong, when they check the premises and find them to be correct. Take ad hominem fallacies for instance.

Person A is stupid, Person A makes statement B, Hence statement B is false.

Premis A and B maybe correct after testing. It doesn't however follow that said statement is false by the virtue of those fallacies.

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MrSchnapps replied on Fri, Jun 29 2012 3:20 PM

The truth-value of the premises is an entirely different thing from the validity of logic itself. You're just equivocating on the definition of logic, which in our case here can only result in conceptual muddiness.

In fact, if you take the perspective of the correspondence theory of truth, then if you still have complains about the premises, then the actual fault is with 'the world out there' that happens to 'occassionally' be ambiguous, rather than any defect intrinsic to logic.

“Remove justice,” St. Augustine asks, “and what are kingdoms but gangs of criminals on a large scale? What are criminal gangs but petty kingdoms?”
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gotlucky replied on Fri, Jun 29 2012 3:43 PM

@Torsten

I'm going to quote myself again:

gotlucky:

A false inference is a false conclusion, which can only result from a set of premises that has at least one false premise or is an incomplete set of premises, or the argument is invalid.

Now let's look at what you said:

Torsten:

No, one can make false conclusions, while all stated premises are correct. People are just more difficult to convince that something is wrong, when they check the premises and find them to be correct. Take ad hominem fallacies for instance.

Person A is stupid, Person A makes statement B, Hence statement B is false.

Premis A and B maybe correct after testing. It doesn't however follow that said statement is false by the virtue of those fallacies.

This falls under the part of my quote where I said "or the argument is invalid".  Even if Person A is stupid and makes B statement, ad hominem is a logically fallacy.  In other words, it is a non sequitur.  The conclusion does not follow from the premises.

Logical fallacy = invalid argument

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