Whence comes logic…

 
Speakpigeon
 
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Speakpigeon
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13 December 2018 06:41
 

Here is your chance to air your views as to whence comes logic.
As a motivation introduction, I observe that most educated people take logic to be a branch of mathematics, or perhaps whatever mathematicians study that they call “logic” since broadly the beginning of the 20th century. Yet, the first systematic presentation of what humans understand of logical rules was made by Aristotle and that was something like 2,400 years ago, and as far as I know, most intellectuals since have accepted Aristotle’s presentation as correct. I’m not aware that anything in mathematical logic shows Aristotle was wrong.
Whatever the case, is it possible to study anything if there isn’t something to study? This suggests logic exists somehow somewhere. But where exactly?
Traditionally, philosophers see rules of logic as necessary and a priori, rather than contingent and empirical. Putnam argued they could be empirical, taking the example of Quantum Physics to support this suggestion. Yet, even a priori rules have to come from somewhere unless you think God the merciful help us sort out the necessary from the contingent.
If we all have our own personal sense of logic, why is it most intellectuals agreed with Aristotle’s logic (and I would assume most people here)? But if we all have the same logic, how come?
And where are we supposed to look when we want to produce a method of logic that, somehow, would be correct?
EB

 
Brick Bungalow
 
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Brick Bungalow
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14 December 2018 01:53
 

I think mathematics emerges from logic and not the other way about.

At it’s most elemental I think logic is not a human invention at all. I think it reduces to principles of causation and efficiency that can be observed in non human communities. I think it’s essentially selection acting upon cognition. I think human imagination manifests in a rather chaotic array and logic is one of the more adaptive among them.

Aristotle can certainly be credited with clever formulations but not invention. It’s more a case of naming than creating.

 
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14 December 2018 05:11
 
Speakpigeon - 13 December 2018 06:41 AM

Here is your chance to air your views as to whence comes logic.
As a motivation introduction, I observe that most educated people take logic to be a branch of mathematics, or perhaps whatever mathematicians study that they call “logic” since broadly the beginning of the 20th century. Yet, the first systematic presentation of what humans understand of logical rules was made by Aristotle and that was something like 2,400 years ago, and as far as I know, most intellectuals since have accepted Aristotle’s presentation as correct. I’m not aware that anything in mathematical logic shows Aristotle was wrong.
Whatever the case, is it possible to study anything if there isn’t something to study? This suggests logic exists somehow somewhere. But where exactly?
Traditionally, philosophers see rules of logic as necessary and a priori, rather than contingent and empirical. Putnam argued they could be empirical, taking the example of Quantum Physics to support this suggestion. Yet, even a priori rules have to come from somewhere unless you think God the merciful help us sort out the necessary from the contingent.
If we all have our own personal sense of logic, why is it most intellectuals agreed with Aristotle’s logic (and I would assume most people here)? But if we all have the same logic, how come?
And where are we supposed to look when we want to produce a method of logic that, somehow, would be correct?
EB

I’d suggest ‘Critique of Pure Reason’ by Kant

 
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15 December 2018 08:46
 
Brick Bungalow - 14 December 2018 01:53 AM

I think mathematics emerges from logic and not the other way about.

I agree with that.

Brick Bungalow - 14 December 2018 01:53 AM

At it’s most elemental I think logic is not a human invention at all. I think it reduces to principles of causation and efficiency that can be observed in non human communities.

Sure, but according to the same reasoning, humans are not even humans at all, they’re just animals, or indeed just matter.
I would agree some logic should be found in other animal species but I don’t expect any would be able to match our logical intuitions. So, perhaps, other animals have a subset of our logic, or something like a less-than-perfect kind of logic…

Brick Bungalow - 14 December 2018 01:53 AM

I think it’s essentially selection acting upon cognition.

Yes, that would be my bet.

Brick Bungalow - 14 December 2018 01:53 AM

I think human imagination manifests in a rather chaotic array and logic is one of the more adaptive among them.

I wouldn’t put logic in quite the same ball park as “imagination”.

Brick Bungalow - 14 December 2018 01:53 AM

Aristotle can certainly be credited with clever formulations but not invention. It’s more a case of naming than creating.

Sure, he couldn’t possibly have invented logic if we’re indeed all logical creatures. But he seems to have originated the most comprehensive method of formal logic for the time, and nothing anybody could improve on for something like 2,400 years. I would even argue nobody substantially improved on it yet. Gentzen generalised Aristotle. And Frege and Russell invented something that’s essentially different from human logic altogether.
EB

 
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16 December 2018 00:16
 

Logic is a set of rules governing statements (the Propositional Calculus) and classification (the Predicate Calculus). They are in my opinion the products of mind, rather than being intrinsic to reality.

It says something about reality in the vicinity of humans that logic is applicable to that reality. I cannot imagine what a segment of reality would be like for which logic would not be applicable, but I can imagine that such a segment of reality exists.

 
 
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17 December 2018 09:32
 
Poldano - 16 December 2018 12:16 AM

Logic is a set of rules governing statements (the Propositional Calculus) and classification (the Predicate Calculus).


This is really called “mathematical logic”, not “logic”.
Logic predates any rule. People didn’t wait for any set of rules to start thinking in a logical way. People had a sense of logic even before Aristotle put a name on the thing and identified the first logical rules. And he had to have a sense of logic before he could identify any logical rules

Poldano - 16 December 2018 12:16 AM

They are in my opinion the products of mind, rather than being intrinsic to reality.

Any rule is the product of a human mind, unless you want to count God in. Logical rules are of course no exception. The question isn’t about the rules we’ve invented. It’s about logic itself.
However, if logic is just something human beings do then logic is part of reality, and “intrinsic” to it. Any similar animal species as us would be able to evolve the same logic.

Poldano - 16 December 2018 12:16 AM

It says something about reality in the vicinity of humans that logic is applicable to that reality. I cannot imagine what a segment of reality would be like for which logic would not be applicable, but I can imagine that such a segment of reality exists.

It’s true our visual sense for example is only applicable to the part of reality where conditions would allow us to see anything. However, whenever we see something, it seems to me that our visual sense is applicable to it. So, possibly not much difference with our sense of logic. Human logic is also myopic outside simple logical truths and simple logical operations. Nobody seems to have any logical intuition outside of that. Which seems a definite limitation. However, that doesn’t say anything about what our brain does outside making us have logical intuitions. I expect all our perceptions to be essentially the result of processes which are essentially logical.
Also, logic doesn’t seem to apply to the physical universe as such. Rather, it is the process our brain uses to make sense of the world. Colours don’t really apply to what we look at. They apply to how we see the world. Same for logic, I think.
EB

 
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18 December 2018 23:14
 
Speakpigeon - 17 December 2018 09:32 AM

...

Logic predates any rule. People didn’t wait for any set of rules to start thinking in a logical way. People had a sense of logic even before Aristotle put a name on the thing
and identified the first logical rules. And he had to have a sense of logic before he could identify any logical rules

That begs the question of whether natural laws exist before someone formulates them in a theory. If natural laws are intrinsic to nature, then formulating them in no way influences nature. It’s the same with logic. There is a sense in which logical rules existed before anyone, Aristotle included, wrote them down, spoke them, or systematized them.

Speakpigeon - 17 December 2018 09:32 AM
Poldano - 16 December 2018 12:16 AM

They are in my opinion the products of mind, rather than being intrinsic to reality.

Any rule is the product of a human mind, unless you want to count God in. Logical rules are of course no exception. The question isn’t about the rules we’ve invented. It’s about logic itself.
However, if logic is just something human beings do then logic is part of reality, and “intrinsic” to it. Any similar animal species as us would be able to evolve the same logic.

It is my position that Logic is an abstraction that applies to some aspects. For Logic to apply to reality in any way, it is necessary to be able to make distinctions about states in reality. Any part of reality about which one cannot make reliable distinctions cannot have Logic applied to it indiscriminately.

“Intrinsic” is a concept that I distrust. It assumes the applicability of the Predicate Calculus to the subject matter under discussion.

Speakpigeon - 17 December 2018 09:32 AM
Poldano - 16 December 2018 12:16 AM

It says something about reality in the vicinity of humans that logic is applicable to that reality. I cannot imagine what a segment of reality would be like for which logic would not be applicable, but I can imagine that such a segment of reality exists.

It’s true our visual sense for example is only applicable to the part of reality where conditions would allow us to see anything. However, whenever we see something, it seems to me that our visual sense is applicable to it. So, possibly not much difference with our sense of logic. Human logic is also myopic outside simple logical truths and simple logical operations. Nobody seems to have any logical intuition outside of that. Which seems a definite limitation. However, that doesn’t say anything about what our brain does outside making us have logical intuitions. I expect all our perceptions to be essentially the result of processes which are essentially logical.
Also, logic doesn’t seem to apply to the physical universe as such. Rather, it is the process our brain uses to make sense of the world. Colours don’t really apply to what we look at. They apply to how we see the world. Same for logic, I think.
EB

You’re slipping and sliding around here, it seems to me. I don’t disagree with anything you’ve said in the excerpt immediately above, but I think it is not to the point of the discussion.

I can offer one likely cognitive function with built-in logical processing, and that is detection of cheating and of the possibility of cheating. Unfortunately, I’m too lazy at the moment to find the references.

 
 
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20 December 2018 09:12
 
Poldano - 18 December 2018 11:14 PM
Speakpigeon - 17 December 2018 09:32 AM

...
Logic predates any rule. People didn’t wait for any set of rules to start thinking in a logical way. People had a sense of logic even before Aristotle put a name on the thing
and identified the first logical rules. And he had to have a sense of logic before he could identify any logical rules

That begs the question of whether natural laws exist before someone formulates them in a theory. If natural laws are intrinsic to nature, then formulating them in no way influences nature. It’s the same with logic. There is a sense in which logical rules existed before anyone, Aristotle included, wrote them down, spoke them, or systematized them.

Then we’re not speaking the same language.

rule
4. A generalized statement that describes what is true in most or all cases: In this office, hard work is the rule, not the exception.

Poldano - 18 December 2018 11:14 PM
Speakpigeon - 17 December 2018 09:32 AM
Poldano - 16 December 2018 12:16 AM

They are in my opinion the products of mind, rather than being intrinsic to reality.

Any rule is the product of a human mind, unless you want to count God in. Logical rules are of course no exception. The question isn’t about the rules we’ve invented. It’s about logic itself.
However, if logic is just something human beings do then logic is part of reality, and “intrinsic” to it. Any similar animal species as us would be able to evolve the same logic.

It is my position that Logic is an abstraction that applies to some aspects. For Logic to apply to reality in any way, it is necessary to be able to make distinctions about states in reality. Any part of reality about which one cannot make reliable distinctions cannot have Logic applied to it indiscriminately.

???

Poldano - 18 December 2018 11:14 PM

“Intrinsic” is a concept that I distrust. It assumes the applicability of the Predicate Calculus to the subject matter under discussion.

No. Intrinsic just means logic is part of reality like anything else that’s real.
There’s no problem applying one’s sense of logic to the problem of formulating rules that would correctly predict our logical behaviour. What matters is that it should work and this has to be validated by observation. This is really the same situation as in science, which may be conceived of as a part of reality trying to describe another part of reality. It works or it doesn’t.

Poldano - 18 December 2018 11:14 PM
Speakpigeon - 17 December 2018 09:32 AM
Poldano - 16 December 2018 12:16 AM

It says something about reality in the vicinity of humans that logic is applicable to that reality. I cannot imagine what a segment of reality would be like for which logic would not be applicable, but I can imagine that such a segment of reality exists.

It’s true our visual sense for example is only applicable to the part of reality where conditions would allow us to see anything. However, whenever we see something, it seems to me that our visual sense is applicable to it. So, possibly not much difference with our sense of logic. Human logic is also myopic outside simple logical truths and simple logical operations. Nobody seems to have any logical intuition outside of that. Which seems a definite limitation. However, that doesn’t say anything about what our brain does outside making us have logical intuitions. I expect all our perceptions to be essentially the result of processes which are essentially logical.
Also, logic doesn’t seem to apply to the physical universe as such. Rather, it is the process our brain uses to make sense of the world. Colours don’t really apply to what we look at. They apply to how we see the world. Same for logic, I think.
EB

You’re slipping and sliding around here, it seems to me. I don’t disagree with anything you’ve said in the excerpt immediately above, but I think it is not to the point of the discussion.

It was my way of disagreeing with your contention that “logic is applicable to reality”. So, as i see it, “logic doesn’t seem to apply to the physical universe as such. Rather, it is the process our brain uses to make sense of the world. Colours don’t really apply to what we look at. They apply to how we see the world. Same for logic, I think.
EB