## Are the Three Laws of Logic correct?

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marsh8472
Posts: 54
Joined: Sun Oct 19, 2014 3:06 pm

### Are the Three Laws of Logic correct?

1) The Law of Identity - An apple is an apple
2) The Law of Non-Contradiction - an apple is not a non-apple
3) The Law of Excluded Middle - it is either true or false that I just ate an apple

Can any of these be shown to be correct without referring back to them to do it?

Wyman
Posts: 941
Joined: Sat Jan 04, 2014 2:21 pm

### Re: Are the Three Laws of Logic correct?

marsh8472 wrote:1) The Law of Identity - An apple is an apple
2) The Law of Non-Contradiction - an apple is not a non-apple
3) The Law of Excluded Middle - it is either true or false that I just ate an apple

Can any of these be shown to be correct without referring back to them to do it?
They are axioms and most would agree that they are self apparent truths, although identity is trickier than the other two. The set of all apples is the same as itself (since sets with the same members are identical). Two apples are identical if they belong to the same sets (i.e. if they have the same properties - Leibnitz' Law)

marsh8472
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### Re: Are the Three Laws of Logic correct?

Wyman wrote:
marsh8472 wrote:1) The Law of Identity - An apple is an apple
2) The Law of Non-Contradiction - an apple is not a non-apple
3) The Law of Excluded Middle - it is either true or false that I just ate an apple

Can any of these be shown to be correct without referring back to them to do it?
They are axioms and most would agree that they are self apparent truths, although identity is trickier than the other two. The set of all apples is the same as itself (since sets with the same members are identical). Two apples are identical if they belong to the same sets (i.e. if they have the same properties - Leibnitz' Law)
They are self-apparent to our minds but how do we know our minds correspond correctly to reality? We would have to show what reality is and what reality is not and show the differences. But in the process of showing those differences we would need to show they are not the same by contradicting each other which just goes back to the law of non-contradiction again.

Blaggard
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### Re: Are the Three Laws of Logic correct?

HexHammer
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### Re: Are the Three Laws of Logic correct?

marsh8472 wrote:1) The Law of Identity - An apple is an apple
2) The Law of Non-Contradiction - an apple is not a non-apple
3) The Law of Excluded Middle - it is either true or false that I just ate an apple

Can any of these be shown to be correct without referring back to them to do it?
That is peasant logic, useless and outdated.

Arising_uk
Posts: 10664
Joined: Wed Oct 17, 2007 2:31 am

### Re: Are the Three Laws of Logic correct?

marsh8472 wrote:1) The Law of Identity - An apple is an apple
2) The Law of Non-Contradiction - an apple is not a non-apple
3) The Law of Excluded Middle - it is either true or false that I just ate an apple

Can any of these be shown to be correct without referring back to them to do it?
Yes.

I can show you an apple and I can eat it or not - should just about cover the lot.

Although I think 2) should be - An apple cannot be and not be an apple.

Impenitent
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### Re: Are the Three Laws of Logic correct?

steve jobs is smiling

-Imp

HexHammer
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### Re: Are the Three Laws of Logic correct?

marsh8472 wrote:1) The Law of Identity - An apple is an apple
2) The Law of Non-Contradiction - an apple is not a non-apple
3) The Law of Excluded Middle - it is either true or false that I just ate an apple

Can any of these be shown to be correct without referring back to them to do it?
One has to be rather unintelligent to believe this nonsense.

There are many kinds of apples, some are cross breeds with other kinds of fruits, and you get something in between.

These days you can gene manipulate an apple, how many % is an apple before it's not an apple?

Is a picture of an apple an apple? No it's a picture, but sometimes there's fraud and you are sold what you believe are apples, but are painted plastic.

What if you spat it out again? ..did you then eat it?

This is exactly why egg heads has problems making robots having a normal conversation, because they condense principles into too narrow interpretations.

Ginkgo
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### Re: Are the Three Laws of Logic correct?

[quote="Ginkgo"]

That's correct Hex, it is related to number 3. "Law of Excluded Middle" Sometimes know as the principle of bivalence. And yes, it does have something to do with robots.

Sorry I forgot to post the link

http://www.wikipedia.org/wiki/Principle_of_bivalence
Last edited by Ginkgo on Mon Feb 09, 2015 3:56 am, edited 2 times in total.

thedoc
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Joined: Thu Aug 30, 2012 4:18 pm

### Re: Are the Three Laws of Logic correct?

HexHammer wrote:
marsh8472 wrote:1) The Law of Identity - An apple is an apple
2) The Law of Non-Contradiction - an apple is not a non-apple
3) The Law of Excluded Middle - it is either true or false that I just ate an apple

Can any of these be shown to be correct without referring back to them to do it?
One has to be rather unintelligent to believe this nonsense.

There are many kinds of apples, some are cross breeds with other kinds of fruits, and you get something in between.

These days you can gene manipulate an apple, how many % is an apple before it's not an apple?

Is a picture of an apple an apple? No it's a picture, but sometimes there's fraud and you are sold what you believe are apples, but are painted plastic.

What if you spat it out again? ..did you then eat it?

This is exactly why egg heads has problems making robots having a normal conversation, because they condense principles into too narrow interpretations.

Knocking down straw men just reinforces the idea that you make stupid arguments. There is nothing valid here that disproves the 3 laws as posted.

marsh8472
Posts: 54
Joined: Sun Oct 19, 2014 3:06 pm

### Re: Are the Three Laws of Logic correct?

thedoc wrote:
HexHammer wrote:
marsh8472 wrote:1) The Law of Identity - An apple is an apple
2) The Law of Non-Contradiction - an apple is not a non-apple
3) The Law of Excluded Middle - it is either true or false that I just ate an apple

Can any of these be shown to be correct without referring back to them to do it?
One has to be rather unintelligent to believe this nonsense.

There are many kinds of apples, some are cross breeds with other kinds of fruits, and you get something in between.

These days you can gene manipulate an apple, how many % is an apple before it's not an apple?

Is a picture of an apple an apple? No it's a picture, but sometimes there's fraud and you are sold what you believe are apples, but are painted plastic.

What if you spat it out again? ..did you then eat it?

This is exactly why egg heads has problems making robots having a normal conversation, because they condense principles into too narrow interpretations.

Knocking down straw men just reinforces the idea that you make stupid arguments. There is nothing valid here that disproves the 3 laws as posted.
Not saying they are incorrect. I just don't see how they can be validated without relying on them during the validation process. I suspect that these laws are just hard-wired into our minds regardless of whether or not they are true.

mickthinks
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Location: Augsburg

### Re: Are the Three Laws of Logic correct?

Not saying they are incorrect.

Then the question you have chosen for your thread title was phrased carelessly, marsh.

I suspect that these laws are just hard-wired into our minds regardless of whether or not they are true.

I suggest they are hard-coded into our language(s) and that truth isn't a helpful concept to apply to any axiom.

marsh8472
Posts: 54
Joined: Sun Oct 19, 2014 3:06 pm

### Re: Are the Three Laws of Logic correct?

Our perception of reality comes with many illusions. Besides the obvious ones like optical illusions, there are things like color, sound, and other qualia that leave us with the impression that this is how the universe really appears. Along with other (arguably) illusions such as free will, dualism, personal identity, dreams, and consciousness. Given these illusions is it not rational to question whether our perception of these laws of logic are correct?

Breath
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### Re: Are the Three Laws of Logic correct?

marsh8472 wrote:1) The Law of Identity - An apple is an apple
2) The Law of Non-Contradiction - an apple is not a non-apple
3) The Law of Excluded Middle - it is either true or false that I just ate an apple

Can any of these be shown to be correct without referring back to them to do it?
These "laws" reflect to a certain extent what goes on in conscious thinking.

Most of us are aware that conscious thinking is not the only thing that is going on.

Like the tip of an iceberg, these three "laws" are trivial.

Arising_uk
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### Re: Are the Three Laws of Logic correct?

Breath wrote:...

Most of us are aware that conscious thinking is not the only thing that is going on.
Such as?

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