What exactly are the three laws of logic? Is there a word for it?

[ydoaPs]

They are fundamental properties of existence itself which the three tautologies I mentioned are our representations of.

No, they're tautologies about the structure of how ideas relate. They have nothing at all to do with "existence itself".

If those weren't properties of existence, logic would not work, because truth statements would be impossible to make.

Really? I've got news for you-they're not fundamental properties of existence. As I've pointed out multiple times before, they don't even always hold.

I have always felt that quantum mechanics may operate in an analogous way.

Take a look at Bell Inequalities.

[Fanghur]

No, they're tautologies about the structure of how ideas relate. They have nothing at all to do with "existence itself".Really? I've got news for you-they're not fundamental properties of existence. As I've pointed out multiple times before, they don't even always hold.Take a look at Bell Inequalities.

 

Wait a minute, let me get this straight. Are you trying to tell me that if I were to make an absolute statement that, for example, "I know that a square circle or a horizontal vertical line are by their very nature impossibilities because they violate the Laws of Identity and Non-Contradiction", that I would be mistaken because those laws do not always apply? Is that what you are trying to tell me?

 

And I am talking about in an abstract sense here. Whatever quantum mechanics may imply, I still stand by my assertion that everything by definition has a nature, because existence is part of something's nature, therefore whatever exists has a nature.

Edited February 22, 2013 by Fanghur

[ydoaPs]

Wait a minute, let me get this straight. Are you trying to tell me that if I were to make an absolute statement that, for example, "I know that a square circle or a horizontal vertical line are by their very nature impossibilities because they violate the Laws of Identity and Non-Contradiction", that I would be mistaken because those laws do not always apply? Is that what you are trying to tell me?

 

And I am talking about in an abstract sense here.

I wasn't aware that geometry was something out in the world. That's right, it's not. It's conceptual....made of propositions. Logics will apply.

[Fanghur]

I wasn't aware that geometry was something out in the world. That's right, it's not. It's conceptual....made of propositions. Logics will apply.

You didn't even answer my question, you're answering some other question. I'm starting to think that you don't believe in an objective reality, because that is certainly the implication which your responses are giving, in which case we may never find common ground. The names of shapes which we have invented are conceptual, but the shapes themselves are not conceptual, they are existential; in a universe with no minds, a grain of salt, or a planet, or an asteroid, etc. would still have whatever shape it has even though there would be no one there to give that shape a title. You just completely dodged my question.

 

In a universe with no minds, could a planet simultaneously be the shape that we in this universe conceptually know of as a sphere and NOT in that shape at the same time in the same sense? No, it could not. It either IS that shape or it is NOT that shape, it can't be both and it can't be neither. That is what I am referring to when I think of the Law of Non-Contradiction and Excluded Middle as being absolute.

 

In a universe with no minds, everything in that universe has a nature, because existence itself IS part of the nature of all that exists. Can something be other than what its essentially is? No, it can't. That is what I mean when I say that the Law of Identity is absolute.

 

It would be nonsensical to suggest otherwise. Equally nonsensical as it would be to suggest that perhaps on some alien planet there is a drawing of a square circle, something is logically impossible because it violates those laws.

Edited February 22, 2013 by Fanghur

[SamBridge]

What makes you think there are laws that must encompass all logic?

[Fanghur]

What makes you think there are laws that must encompass all logic?

Not logic. I have made this point several times already. I consider the laws of identity, non-contradiction and excluded middle to be fundamental properties of existence, not conceptual law based on logic, and by my own logic to apply even at the quantum level; an electron, while it exists, is an electron and it is not NOT an electron.

 

Do me a favour, ydoaPs and anyone else, and watch this 5 part debate between Matt Dillahunty and Matt Slick on this issue; my view is identical to Dillahunty's. Maybe that will actually get my point across.

 

[ydoaPs]

The names of shapes which we have invented are conceptual, but the shapes themselves are not conceptual, they are existential;

No, they're not. There is no such thing in reality as a perfect circle. Math is a descriptive abstraction which approximates how the universe behaves. So, any logic about geometry is still about propositions.

That is what I am referring to when I think of the Law of Non-Contradiction and Excluded Middle as being absolute.

They are simply three ways of describing one tautology about propositions. They are in no way about anything apart from propositions. Mistaking them for statements about reality isn't just wrong. In the case of the "law of identity", it's incoherent to think they are statements about ontological reality.

 

The law of identity is about reflexivity of propositions. What on earth does it even mean to say that an object is reflexive?

 

As I've said before, the law of non-contradiction, while it may look prima facie like it can be a metaphysical statement about reality, DOES NOT HOLD IN GENERAL. We can put things in superposition of mutually exclusive states such as an electron having spin up and spin down at the same time.

 

Same thing for excluded middle. Let's say that electron is part of an atom. Now, we pick a point in the orbital. Is the electron there or isn't it? The answer is neither.

 

"Logical absolutes" are a fairy tale apologists made up to tell people who don't know anything about logic. End of story.

Not logic. I have made this point several times already. I consider the laws of identity, non-contradiction and excluded middle to be fundamental properties of existence

And, as I've explained several times already, you are wrong.

[PeterJ]

You still seem to be missing what logic is about. Logic isn't about rocks, trees, or gods; it's about ideas. What's more, it's not even about the content of the ideas (you'll need probability theory for that)-it's just about the structure. Logic is the calculus of how ideas relate to each other. That's it. It has absolutely nothing to do with anything in the universe other than ideas.

 

That being said, logics aren't absolute. There are cases where basic bivalent sentential logic is inadequate. It doesn't work for QM, since it is bivalent and reality on the quantum level isn't. That is, our ideas about reality will be contradictions in sentential logic if they accurately describe the QM world.

.

 

This second para is not correct. If you examine Aristotle's rules carefully you will see that these contradictions you speak of are not true contradicitons as defined by Aristotle, and therefore are not subject to his rules. There is nothing in QM that requires a modification to those rules.

 

I would recommed Whitaker's book on Aristotle 'De interpretatione' for an explanation for why QM is not a problem for this logic. The father of philosophy was no fool.

Edited March 4, 2013 by PeterJ

[ydoaPs]

This second para is not correct. If you examine Aristotle's rules carefully you will see that these contradictions you speak of are not true contradicitons as defined by Aristotle, and therefore are not subject to his rules. There is nothing in QM that requires a modification to those rules.

Yes, there is. I've given multiple examples.

 

The father of philosophy was no fool.

I'd suggest you stop trying to justify the philosophy from people who believed their underpants were made of fire and move into the modern (not to be confused the Modern) era. Simple first order logic does not always apply.

[PeterJ]

Okay. Sorry. I thought you wanted to understand the issues.

[ydoaPs]

Okay. Sorry. I thought you wanted to understand the issues.

Thanks for the baseless condescension. Do you have anything of worth to contribute?

 

I've given multiple examples of when bivalence doesn't hold and your reply is "nuh uh". Pointing to someone who disagrees with everyone about whether or not first order bivalent predicate logic is universal in scope isn't going to cut it. You're going to need more than an appeal to authority here.

[PeterJ]

 

Thanks for the baseless condescension. Do you have anything of worth to contribute?

I've given multiple examples of when bivalence doesn't hold and your reply is "nuh uh". Pointing to someone who disagrees with everyone about whether or not first order bivalent predicate logic is universal in scope isn't going to cut it. You're going to need more than an appeal to authority here.

Yes, you're right. Sorry. But these things work both ways.

I'm not appealing to authority. I'd like to discuss a specific instance of your choosing. This gives you a chance to pick your best example. I am not going to trawl back through your previous posts for an example that suits me.

Even if authority should not be be our final appeal I do think it's worth noting that my view accords with Aristotle's and yours does not. It is possible that you underestimate him. He is quite well respected even today. Personally I consider his idealisation and formalisation of the way in which human beings reason a work of genius, But most people do not reason in his idealised way and do not apply his rules rigorously. They forget his warnings about the easy-to-make errors that can creep in.

What you would have to do to in order to show that QM requires a modification to Aristotle's laws of thought is find an instance where two propositions take the form A/ not-A, where one of them is true and where according to logic if one of them is true the other simply must be false, and then show that in QM there are pairs of statements which obey this logical rule, but for which the scientific evidence proves that it is not the case that one is true and one is false. This would not be an easy thing to do.

Heisenberg uses the example 'Here is a table' and 'Here is-not a table'. He argues that in order for both statements to be true or for both to be false, as they seem to be in QM for some cases of paired statements. we would have to modify Aristotle's 'laws of thought', or rules for the dialectic, in particular the law of excluded middle. But there are problems with this view.

If a pair of statements does not obey Aristotle';s rule for a true contradictory pair, (such that one is true and one is false), then the laws of thought would not apply to it. It would be undecidable. It would be a category-error. For the pair of statements considered by Heisenberg it is not being proposed that one is true and one is false, and so no problem arises for logic or for human reason. Aristotle's rules allow for a logic of contradictory complementarity such as that used in QM without need of any modification, and he goes to a great deal of trouble to make this clear. Again I will mention Whittakers book on De Interpretatione, since I think any physicist would find it interesting and important in respect of QM. .

The contradictory and complementary counterpart to A would be not-A, Thus, for example, if we take the simplest example of a seemingly paradoxical duality in physics, the wave-particle duality, we must be careful not to oppose the statements 'an electron is a particle' and 'an electron is a wave'. This is not a true contradictory pair and as a dialectical question it is a category-error. It is undecidable, Physics does not propose that one of these statements is true and the other is false. It proposes that the truth is a lot more weird than this.

So the question here is whether there is an example from QM of a true contradictory pair of statements about the world where the data shows that it is not the case that one is true and one is false.

The reason I feel strongly about this is that in my opinion it is precisely this misunderstanding of Aristotle's logic that prevents physicists from being able to solve metaphysical problems.and find a comprehensible interpretation for QM. The laws are forever being applied to category-errors with no regard for Aristotle, and thus certain ideas are rejected as unreasonable on the grounds of what is incorrect reasoning. Nature then becomes incomprehensible. Edited March 4, 2013 by PeterJ