'What is logic?'

[Nearly Sane]

Looking at the history of logic and its interaction with other influences


https://aeon.co/essays/the-rise-and-fall-and-rise-of-logic

[Walter]

Looking at the history of logic and its interaction with other influences


https://aeon.co/essays/the-rise-and-fall-and-rise-of-logic

please, not again!

[Nearly Sane]

please, not again!

As pointed out before, you aren't forced to read anything.

[Walter]

As pointed out before, you aren't forced to read anything.

but are you being forced to post?

[Nearly Sane]

but are you being forced to post?

No, and I've explained this to you before. I post things I find intetesting, I make an effort to do so because if there aren't new topics the forum will wither and die, and as a mod I am trying to avoid that.

[Udayana]

It's very wordy, reviews some history but does not really answer the question posed.

[Nearly Sane]

It's very wordy, reviews some history but does not really answer the question posed.

I think, as so often, the headline is probably not what the article is about. I don't see it as 'wordy', indeed it reads as a lot of ellipsis.

[Bubbles]

Looking at the history of logic and its interaction with other influences


https://aeon.co/essays/the-rise-and-fall-and-rise-of-logic

Logic to me is " what reasonably follows on from"

So people years ago made what they saw as logical ideas, with the knowledge they had at the time.

Nowadays with modern science as we know it, their ideas don't look so logical.

One day, as science progresses maybe our own ideas won't look as logical as we think they are 🙂

IMO the history of logic is tied in with knowledge possessed at the time.

[Sriram]

Logic to me is " what reasonably follows on from"

So people years ago made what they saw as logical ideas, with the knowledge they had at the time.

Nowadays with modern science as we know it, their ideas don't look so logical.

One day, as science progresses maybe our own ideas won't look as logical as we think they are 🙂

IMO the history of logic is tied in with knowledge possessed at the time.

Yes...I agree. Logic is not fixed in stone. It changes with time, knowledge, circumstances and so on. All logic is not mathematics. 

What may seem reasonable and logical with a certain perception could seem completely unreasonable and illogical with a different perception.  It could also depend on ones background, culture and social environment.

[torridon]

Yes...I agree. Logic is not fixed in stone. It changes with time, knowledge, circumstances and so on. All logic is not mathematics. 

What may seem reasonable and logical with a certain perception could seem completely unreasonable and illogical with a different perception.  It could also depend on ones background, culture and social environment.

That is wrong.

You continue to mistake comprehension for logic.  The area of a circle was always related to the square of its radius by a factor of 3 and a bit long before Pythagoras figured it out. Logic expresses truths and truths do not vary based on the cognitive ability of bipedal African apes to comprehend them.

[Gordon]

Yes...I agree. Logic is not fixed in stone. It changes with time, knowledge, circumstances and so on. All logic is not mathematics. 

What may seem reasonable and logical with a certain perception could seem completely unreasonable and illogical with a different perception.  It could also depend on ones background, culture and social environment.

You seem to be arguing in favour of subjective logic, which is an oxymoron.

[Udayana]

Logic to me is " what reasonably follows on from"

So people years ago made what they saw as logical ideas, with the knowledge they had at the time.

Nowadays with modern science as we know it, their ideas don't look so logical.

One day, as science progresses maybe our own ideas won't look as logical as we think they are 🙂

IMO the history of logic is tied in with knowledge possessed at the time.

That is a very superficial take, though how it can be used in general speech. More formally, it is a set of definitions and rules which underlies deductive reasoning, maths and science. It is not something that changes with time, where science has progressed, ie. where we have come different conclusions than earlier people, it is not because logic itself has changed, but that we have gathered a better set of facts to which to apply logical thinking or, occasionally, we have identified mistakes in how logic has been used.

[Stranger]

Both Rose and Sriram have misunderstood. Logic is not what 'seems reasonable' to a person or culture. Perhaps an example would help? Take this argument:-

All items made of granite are magic.
All coffee tables are made of granite.
Therefore all coffee tables are magic.

This is a logically valid argument. This is because it is impossible for its premises to be true and its conclusion to be false. However it is obviously nonsense in terms of what we know about the real world: its premises are clearly false (it is said not to be sound).

Logic cannot, by itself, tell us anything about the real world.

[Stranger]

The area of a circle was always related to the square of its radius by a factor of 3 and a bit long before Pythagoras figured it out.

Well strictly speaking, the formula for the area of a circle (A = πr²) logically follows from the axioms of Euclidean geometry, which don't exactly correspond with the space that we inhabit. It's a very good approximation where gravity is weak, but not actually correct.

[Udayana]

Well .. it's 100% correct within the system of Euclidean geometry but, as you say,  we have found that that system does not exactly match "real space".

The real universe is not obliged to conform to any of the mathematical or physical models we develop.

I suppose it doesn't have to conform to logic and causality either, but how else could we understand or discuss any of it?

[Sriram]

Logic is defined as....


1. the science that investigates the principles governing correct or reliable inference.

2.a particular method of reasoning or argumentation:We were unable to follow his logic.

3.the system or principles of reasoning applicable to any branch of knowledge or study.

4.reason or sound judgment, as in utterances or actions:There wasn't much logic in her move.

5.convincing forcefulness; inexorable truth or persuasiveness:


logic is not just about mathematics....2+2=4 etc. That is only one specific type of logic.

Check out

https://en.wikipedia.org/wiki/Logic

Logic is related to culture, background and whatever seems reasonable at that time, in that social culture, with that knowledge and in that situation.   For example....in a culture which is largely religious...it would be very logical to suppose that a God created the world. Logically there is no other explanation at all.  To argue that the universe got generated by chance...would be very illogical and unreasonable.

In an atheist culture it would be logical to assume that some natural law generated the universe.   

[Stranger]

Check out

https://en.wikipedia.org/wiki/Logic

Logic is related to culture, background and whatever seems reasonable at that time, in that social culture, with that knowledge and in that situation.   

The page you referenced doesn't even contain the word 'culture'. What it does say, in the first section (Concepts) is

The concept of logical form is central to logic. The validity of an argument is determined by its logical form, not by its content.

Which was my point in #12.

For example....in a culture which is largely religious...it would be very logical to suppose that a God created the world. Logically there is no other explanation at all.  To argue that the universe got generated by chance...would be very illogical and unreasonable.

In an atheist culture it would be logical to assume that some natural law generated the universe.

What you have pointed out here is not a difference in logic but a difference in what premises are considered to be true and hence what conclusions are arrived at.

There are, of course, colloquial and less formal uses of the term but certainly when people talk about logic in debate, in particular logical fallacies (which tend to be mentioned a lot here) then it is in the formal sense.

Today, logic is a branch of mathematics and a branch of philosophy. In most large universities, both departments offer courses in logic, and there is usually a lot of overlap between them.

http://plato.stanford.edu/entries/logic-classical/#1

[Gordon]

Logic is related to culture, background and whatever seems reasonable at that time, in that social culture, with that knowledge and in that situation.

.

Wrong: logic isn't culture-dependent.

For example....in a culture which is largely religious...it would be very logical to suppose that a God created the world. Logically there is no other explanation at all

The extent to which logical axioms are recognised and understood may be culturally-dependent, and anyway 'God' isn't a claim that is usually made on the basis of logic: it is usually made on the basis of fallacies.

To argue that the universe got generated by chance...would be very illogical and unreasonable.

Who argues this?

In an atheist culture it would be logical to assume that some natural law generated the universe.

Which atheist culture would this be?

[Walter]

No, and I've explained this to you before. I post things I find intetesting, I make an effort to do so because if there aren't new topics the forum will wither and die, and as a mod I am trying to avoid that.

here's a tip for you . If your aim is to keep this forum alive why not post something the majority might find interesting rather than your own pet subject.
It looks to me as though you like the sound of your own typing   

[Sriram]

That is wrong.

You continue to mistake comprehension for logic.  The area of a circle was always related to the square of its radius by a factor of 3 and a bit long before Pythagoras figured it out. Logic expresses truths and truths do not vary based on the cognitive ability of bipedal African apes to comprehend them.

torridon......

Logic is NOT mathematics..repeat NOT mathematics!  2+2=-4 is only one specific  type of logic that seems to be valid for all time (In fact, I am not even sure if  maths is valid for all time and all space...but that's a different argument!)

Logic is about reasonableness. (Check out the dictionary definitions). It is time, knowledge and culture (belief, lifestyle) dependent. 

As I have said...'God created the world' is perfectly logical.  'The sun goes around the earth' is perfectly logical. And so many other such normal phenomena for which we today have different explanations.   

1000 years from today everything that seems perfectly logical to us today may seem nonsensical to those people.

Some people tend to hijack words like logic, energy, science etc. and confine their usage to very narrow domains. This robs them of their larger and wider meanings. And then they keep arguing about words and semantics. 

[torridon]

torridon......

Logic is NOT mathematics..repeat NOT mathematics!  2+2=-4 is only one specific  type of logic that seems to be valid for all time (In fact, I am not even sure if  maths is valid for all time and all space...but that's a different argument!)

Logic is about reasonableness. (Check out the dictionary definitions). It is time, knowledge and culture (belief, lifestyle) dependent. 

As I have said...'God created the world' is perfectly logical.  'The sun goes around the earth' is perfectly logical. And so many other such normal phenomena for which we today have different explanations.   

1000 years from today everything that seems perfectly logical to us today may seem nonsensical to those people.

Some people tend to hijack words like logic, energy, science etc. and confine their usage to very narrow domains. This robs them of their larger and wider meanings. And then they keep arguing about words and semantics.

Oh dear, you are just sticking to your very superficial understanding of the concept of logic.  There is a difference between what might seem logical at any point in time and what actually is logical, but that is not because logic varies, it is simply because our comprehension has altered.  Logic itself is abstract and self referential and not dependent on any context, such as human culture.  If it were then we this would manifest most immediately in maths and international trade would not be viable if numbers added up differently from country to country.  Not that maths is the only form of logic, it is merely the manifestation of logic that is easiest to exemplify in discussion. I think you didn't bother to read the Wiki page on logic you posted up; there is nothing in there to support your claims.

[Stranger]

Logic is NOT mathematics..repeat NOT mathematics!  2+2=-4 is only one specific  type of logic that seems to be valid for all time (In fact, I am not even sure if  maths is valid for all time and all space...but that's a different argument!)

Logic is about reasonableness. (Check out the dictionary definitions). It is time, knowledge and culture (belief, lifestyle) dependent.

Rant all you like but, loose and colloquial meanings aside, if you study logic as an academic subject or read a book about it, you will be studying it the sense that myself and others have been outlining. See quote from The Stanford Encyclopedia of Philosophy in #16.

Some people tend to hijack words like logic, energy, science etc. and confine their usage to very narrow domains. This robs them of their larger and wider meanings. And then they keep arguing about words and semantics.

If you were writing poetry the situation would be different - but this is a discussion forum and it is appropriate to use terms according to the context. Hence logic in the philosophical (and mathematical) sense and energy in the scientific sense.

By the way 2 + 2 = 4 is not logic, even in the mathematical sense - it is a logical consequence of how integers, the addition operator and equality are defined.

[splashscuba]

here's a tip for you . If your aim is to keep this forum alive why not post something the majority might find interesting rather than your own pet subject.
It looks to me as though you like the sound of your own typing   

It may not be interesting to you (in which case don't take part) but as you can see, by the debate it has generated, it is interesting to others, including me.

If you want to debate whether he posts stuff because he likes the sound of his typing, why don't you raise the topic.

[Sriram]

Oh dear, you are just sticking to your very superficial understanding of the concept of logic.  There is a difference between what might seem logical at any point in time and what actually is logical, but that is not because logic varies, it is simply because our comprehension has altered.  Logic itself is abstract and self referential and not dependent on any context, such as human culture.  If it were then we this would manifest most immediately in maths and international trade would not be viable if numbers added up differently from country to country.  Not that maths is the only form of logic, it is merely the manifestation of logic that is easiest to exemplify in discussion. I think you didn't bother to read the Wiki page on logic you posted up; there is nothing in there to support your claims.

There is nothing called  'actually logical'. Nothing is ACTUALLY logical....for heavens sake. Logic is not about facts or mathematical accuracy....it is about what seems reasonable. And what seems reasonable varies with people, time, knowledge, culture, beliefs and so on.

Even facts can seem illogical. We live on a globe flying around the sun at several hundred kms per hour. That would seem illogical but is still a fact.

You may think that people of earlier times were ignorant and our knowledge of today is something of a supreme kind and therefore our LOGIC of today based on  scientific knowledge is irrefutable. Wrong! What we consider logical today could seem illogical and even stupid just 100 years from today.

For example...Emergent Properties arising due to some  inner Intelligence seems perfectly logical to me. But Emergent Properties arising with absolutely no cause seems perfectly logical to you (but not to me).  Neither of these is ACTUALLY logical....whatever the real fact may be ultimately.  These are just view points both of which are logical in their own right.

[Stranger]

There is nothing called  'actually logical'. Nothing is ACTUALLY logical....for heavens sake.

Amazing ignorance, followed by total confusion...

Logic is not about facts...

You are (by pure coincidence, it would seem) right.

...or mathematical accuracy...

Well mathematical accuracy is part of a system that is logical but (in a sense) you are right that it isn't what logic is about.

...it is about what seems reasonable.

No, it is not - see example in #12.

Even facts can seem illogical. We live on a globe flying around the sun at several hundred kms per hour. That would seem illogical but is still a fact.

A fact in itself is neither logical nor illogical. As you said before (but seem to have forgotten in the course of writing the post), logic is not about facts.

You may think that people of earlier times were ignorant and our knowledge of today is something of a supreme kind and therefore our LOGIC of today based on  scientific knowledge is irrefutable. Wrong! What we consider logical today could seem illogical and even stupid just 100 years from today.

A total misunderstanding. Logic is a way of reasoning - it is used in science but no scientific conclusions can be reached by logic alone. Logic cannot tell us about the world.

From previous experience, I guess you'll stubbornly cling to your ignorance, but ignorance should not go unchallenged...