## Are the Three Laws of Logic correct?

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HexHammer
Posts: 3194
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### Re: Are the Three Laws of Logic correct?

thedoc wrote:
HexHammer wrote:
thedoc wrote:There is a popular idea that humans only use 10% of their brain,
One only use 10% at a time, poven in Mythbusters.

Yes, but most members here try to overlook your deficiency.
Try for once to say something intelligent, just once!

Owen
Posts: 25
Joined: Tue Apr 23, 2013 11:21 am

### 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)
Wrong. They are not axioms of any system that I have read. What system of logic has these three theorems as axioms??

Owen
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Joined: Tue Apr 23, 2013 11:21 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.
2 & 3 are 'theorems' and can be proven within a first order system.

1. is an axiom of the system (FOPL=), (all x)(x=x) is an axiom there, but
(all x)(x=x) is not an axiom in second order logic, it is a theorem.

Each of the so-called laws are not axioms but rather they are derived theorems of second order logic.

Wyman
Posts: 968
Joined: Sat Jan 04, 2014 2:21 pm

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

Owen 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?
Yes.
2 & 3 are 'theorems' and can be proven within a first order system.

1. is an axiom of the system (FOPL=), (all x)(x=x) is an axiom there, but
(all x)(x=x) is not an axiom in second order logic, it is a theorem.

Each of the so-called laws are not axioms but rather they are derived theorems of second order logic.
http://en.wikipedia.org/wiki/Law_of_tho ... ional_laws

They don't have to be axioms (they can be derived from other axiom systems), but in calling them 'laws' they fit under the informal notion of 'axiom' as being self evidently true. Whether there exists an actual axiom system including those three, I could do it right here if I chose.

HexHammer
Posts: 3194
Joined: Sat May 14, 2011 8:19 pm
Location: Denmark

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

Wyman wrote:http://en.wikipedia.org/wiki/Law_of_tho ... ional_laws

They don't have to be axioms (they can be derived from other axiom systems), but in calling them 'laws' they fit under the informal notion of 'axiom' as being self evidently true. Whether there exists an actual axiom system including those three, I could do it right here if I chose.
What you speak of, is how very naive and gullible people think, yearh..

Wyman
Posts: 968
Joined: Sat Jan 04, 2014 2:21 pm

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

HexHammer wrote:
Wyman wrote:http://en.wikipedia.org/wiki/Law_of_tho ... ional_laws

They don't have to be axioms (they can be derived from other axiom systems), but in calling them 'laws' they fit under the informal notion of 'axiom' as being self evidently true. Whether there exists an actual axiom system including those three, I could do it right here if I chose.
What you speak of, is how very naive and gullible people think, yearh..

Naive people think that the law of non-contradiction is self-evident?

Hex is an ass AND Hex is not an ass. I firmly believe that only one of these sentences can be true.
Last edited by Wyman on Fri Mar 13, 2015 4:13 pm, edited 1 time in total.

Arising_uk
Posts: 11771
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### Re: Are the Three Laws of Logic correct?

Breath wrote:Now, in your opinion, is or isn't thinking going on that is not conscious while asleep? ...
No. 'Thinking' involves the conscious use, via memory, of the representations from the senses. Although I think thinking thinking is when a language is used and what I said earlier I call 'thoughting' thinking.

HexHammer
Posts: 3194
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Location: Denmark

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

Wyman wrote:
HexHammer wrote:
Wyman wrote:http://en.wikipedia.org/wiki/Law_of_tho ... ional_laws

They don't have to be axioms (they can be derived from other axiom systems), but in calling them 'laws' they fit under the informal notion of 'axiom' as being self evidently true. Whether there exists an actual axiom system including those three, I could do it right here if I chose.
What you speak of, is how very naive and gullible people think, yearh..

Naive people think that the law of non-contradiction is self-evident?
I've explained the concept of self evidence earlier in this very thread.

Also this is excatly how demagogues convice utterly stupid people, people such as you.

Wyman
Posts: 968
Joined: Sat Jan 04, 2014 2:21 pm

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

HexHammer wrote:
Wyman wrote:
HexHammer wrote:

Naive people think that the law of non-contradiction is self-evident?
I've explained the concept of self evidence earlier in this very thread.

Also this is excatly how demagogues convice utterly stupid people, people such as you.
Gee, Hex, I went through your posts and couldn't find any mention of self-evidence. Was it deleted?

You do realize that modern logic is 'mathematical' logic - a description of the principles of mathematics? Mathematics has helped build a lot of those bridges and buildings you go on about. I.e. it has proven very useful.

Owen
Posts: 25
Joined: Tue Apr 23, 2013 11:21 am

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

Wyman wrote:
Owen 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?
Yes.
2 & 3 are 'theorems' and can be proven within a first order system.

1. is an axiom of the system (FOPL=), (all x)(x=x) is an axiom there, but
(all x)(x=x) is not an axiom in second order logic, it is a theorem.

Each of the so-called laws are not axioms but rather they are derived theorems of second order logic.
http://en.wikipedia.org/wiki/Law_of_tho ... ional_laws

They don't have to be axioms (they can be derived from other axiom systems), but in calling them 'laws' they fit under the informal notion of 'axiom' as being self evidently true. Whether there exists an actual axiom system including those three, I could do it right here if I chose.
First you claim that they are axioms
Wyman: "They are axioms and most would agree that they are self apparent truths, although identity is trickier than the other two."
and now you say they are not axioms ??

Since you have changed your mind, I now agree. The three so-called laws of thought are theorems of classical logic, not axioms of classical logic.

Wyman
Posts: 968
Joined: Sat Jan 04, 2014 2:21 pm

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

ax·i·om
ˈaksēəm/Submit
noun
plural noun: axioms
a statement or proposition that is regarded as being established, accepted, or self-evidently true.
"the axiom that supply equals demand"
synonyms: accepted truth, general truth, dictum, truism, principle;

The second time I used the word, I was referring to the technical sense as I was responding to your post which obviously took that sense. Are we really arguing over such trivial semantics - whether I should have used 'law' instead of 'axiom' as the latter can be used in two different ways?

HexHammer
Posts: 3194
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Location: Denmark

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

Wyman wrote:Gee, Hex, I went through your posts and couldn't find any mention of self-evidence. Was it deleted?

You do realize that modern logic is 'mathematical' logic - a description of the principles of mathematics? Mathematics has helped build a lot of those bridges and buildings you go on about. I.e. it has proven very useful.
FFS, went thought my posts, can't find the damn post, seems deleted or it's in some weird thread I can't remember. Yes, maybe it was deleted, but who knows.

..my apologies for sending you on a wild goose chase.

Yes I know many use math to apply logic to their thinking, but that doesn't make them able to solve unknown problems, or handle fraud in their equation.

Unknown factors simply doesn't show.

My example was that a biologist saw that the elephants in Africa was very numerous and saw how much they ate each day and would ravage nature in a short while, he suggested that their numbers had to be decimated to save nature as it was a logical consequence and self evident ..and yadda yadda, a group of scientists confirmed his findings and about 40,000 elephants.
But the biologist and scientists hadn't included 1 tiny unknown factor, that they elephants would stomp the ground firm, so the moist soil wouldn't dry out, and they actually prevented desertification. Consequently the nature sufferd greatly not only plants, but animal life.

Also the white man has for centuries considered savages as inferior people, and seen themselves as far superior, seen savages as stupid and unintelligent, etc ..it was self evident.

Too often this "self-evidence" has failed utterly, as it's a estimate based on pure speculation and guesswork, and most people in this world sucks at guessing.

Dalek Prime
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Location: Living in a tree with Polly.

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

Impenitent wrote:steve jobs is smiling

-Imp
I doubt he's doing much of anything. Even being Steve Jobs.

Eodnhoj7
Posts: 3573
Joined: Mon Mar 13, 2017 3:18 am

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

marsh8472 wrote:
Sun Feb 08, 2015 12:07 am
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 correct.

They can be viewed as synonymous to:

1) The Law of Identity - An apple is an apple
a) Positive Value
b) stability in logical structure
c) 1 = 1

2) The Law of Non-Contradiction - an apple is not a non-apple
a) Negative value
b) absence of stability in logical structure
c) 1 ≠ -1

3) The Law of Excluded Middle - it is either true or false that I just ate an apple
a) Neutral value
b) synthesis of stability and non-stability
c) 0 = 1-1 or 0 is 1 and -1 or -1,0,1

GreatandWiseTrixie
Posts: 1547
Joined: Tue Feb 03, 2015 9:51 pm

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

Eodnhoj7 wrote:
Sat Nov 04, 2017 3:42 pm
marsh8472 wrote:
Sun Feb 08, 2015 12:07 am
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 correct.

They can be viewed as synonymous to:

1) The Law of Identity - An apple is an apple
a) Positive Value
b) stability in logical structure
c) 1 = 1

2) The Law of Non-Contradiction - an apple is not a non-apple
a) Negative value
b) absence of stability in logical structure
c) 1 ≠ -1

3) The Law of Excluded Middle - it is either true or false that I just ate an apple
a) Neutral value
b) synthesis of stability and non-stability
c) 0 = 1-1 or 0 is 1 and -1 or -1,0,1
That is one of the flaws of logic, it does not account for temporalities.
For instance, is Peter happy or sad?
Maybe he's happy 1 minute, sad the next.
Or happy and sad at the same time.

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