Why use logic?

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Why use logic? Why is logic valid? What makes logic valid? I want your opinions on this matter, people. Perhaps even discussions on the nature of logic. Pick the best answer on the poll, pick "other" if you have a category of criticism I have completely missed, not if you cannot decide between 2 other reasons, in the latter case just pick the best answer.

well, I think logic is very useful, because it helps to form a coherent structure to propositions and arguments to support their validity in the search for knowledge, answers, proofs, truth or truths, although logic is more than that.

I believe logic is just a tool and does not provide answers or "truths" by itself.




As for the poll options:

It is commonsense that logic is valid
I think commonsense is not always, if not often, reliable.

Because the notion that logic is invalid is inconceivable
I tend to agree with this, if we speak about coherence and validity of propositions.

God makes logic valid
It can be argued by believers that logic is a human construct and God goes beyond that.

Logic survives a lot of criticism
I'm not sure about that, I think anything can and should be subjected to criticism.

I prefer to use of logic
Yes, although logic doesn't seem to provide a unique answer, several propositions, with different and opossite views rely on logic.

Logic is a fiction that seems to have a place
Perhaps.

I don't know why to use logic
I don't know how to use logic

I think logic is perverse
well, it depends, I suppose everything misused or used to fit an agenda could become perverse.

AG is so freakin' awesome!!
Is that logical?


This is my mere opinion on it though.

Other: it gets good results.

Logic: it works, b*****s.
A little like science.

No doubt logic is useful. Bitching is also satisfying at times.

Hmm... yeah, can you prove it works without using logic? Or is this a circular matter of logic claiming it's own functionality? If the latter, why not anything else?


Yeah, I wanted to go through all of the answer options critically, but I decided not to.

In any case, it seems odd to justify logic using common sense given the number of things that common sense justifies that are wrong. I mean, perhaps the term "common sense" is an improper term for what is going on, but I can't think of a better term.

'Logic' can refer to a lot of very different things. It does not always mean 'reason', which I think you are talking about(?).
Can you be more specific?

All these answers rely on one form of logic or another to make sense. Even the question; 'is logic valid?' talks about 'validity', which is a concept inseparable from logic.

It is not valid to try to justify something by use of that something. If you want to prove 2x3=6, you can not use 2x3=6 as part of your proof because you you are using the thing you have not proved yet to prove something. Likewise, it is wrong to use logic to prove logic is valid.
Of course, it makes even less sense to use logic to argue that logic is not valid or that it is a helpful fiction.

Even to decide not to use logic in our argument is a logical (as in rational) decision made from the above.

However, I see no alternative.
We have hit an impregnable paradox.

Can you be more specific with what you are talking about? I am conflating both rationality, and philosophical logic in my usage, and I cannot think of what else you would be talking about.


Very difficult to separate from logic, however, one could argue that logic does not provide itself validity, but rather undermines it's own validity.


I know that, which is part of the question. And the latter problem is also a part of the issue as well.


True.

I know. Fun, ain't it? And aren't you glad that you hit upon it?

There are many fully described, rigid, formal logic systems, often based on mathematical, semantic, first order logic etc. and on the other hand there are 'common sense' logic systems, which tend to be much more lose and fluffy.

Many forms of logic do not make any epistemological claims, so it does not make sense to talk about their validity.
Others rest upon axioms that guarantee their validity, so it does not make sense to question the validity of the logic system unless you want to attack the axioms, but that is a little pointless as more often than not, no attempt is made to justify them in the first place.

Almost every formal logic devised has it's own criticisms.

Examining the validity of formal logic and common sense logic are two very different tasks.
Examining the validity of the various different formal logic systems is something that must be done on a case by case basis.
One validation or refutation does not fit all.

I think logic is the philosophical equivalent to physics. If you drop a ball from a building roof it will fall at 9m/s^2. If you ask someone what will happen if you drop a ball from a building they will say "Logically I believe it will fall at 9m/s^2".

Why use it though? I think its the closest we can get to objective observation of our environment. Sure there are a lot of possible errors in measuring initial conditions or structuring relations but as another has stated "It works, b*****s".

I think the more valid question is "What else could possibly reliably give us correct answers to our questions?".

Because it Works. Simple as that.

logic works because your mom shoves squids in unspeakable areas causing a smell so nasty that everyone falls down to logic as the most effective means of coming to a conclusion and finding an eventual correct answer.

/totally proved it
//no logic needed
///your mom is really smelly dude

The fact that I indicated it gets good results ("it works, b*****s") should imply that empiricism bears out the validity of logic. Logic and science both consistently work and are vindicated by the results of empirical analysis and observation.

To paraphrase:

"That which is proved by empirical analysis and observation is valid.
Logic and science are proven by empirical analysis and observation.
Therefor logic is valid."


That is a whole lot of logic you are using to prove logic is valid.

Fine then. Show me an alternate means of demonstrating that anything is valid. Is logic then simply a logical necessity? It does not seem escapable.

QFT

Logic is ultimately based on observation and empirical tests in the physical universe. It is the most fundamental aspect of science. That it has applications in our minds is ultimately an extremely potent indicator of the nature of our minds.

Math, a language derived rigorously from logic (which is in turn derived from the most simple laws of Newtonian physics), is able to accurately predict untested properties of the physical universe. Antimatter is a fine example: its existed was hypothesized due to else-wise inexplicable negative signs turning up in theoretical mathematical models.

Ultimately we use logic (and math) because it explains the universe, of which we are a part, so that we can better live in it.

- - -

An interesting matter does arise if you assert that math is simply translating more complex logical premises for assimilation by the human mind, and that at the smallest scales the universe follows non-Newtonian laws... it becomes apparent that we are simply translating concepts to a scale that makes sense. Quantum-based logic, and quantum-based math, seem to provide a much more accurate, if difficult to understand, basis of understanding the universe. It follows that human minds are ill adapted to comprehend every aspect of the universe at every scale. In example, the human mind is very good at linear approximations, but sucks at rapidly computing non linear approximation, much more then the actual difficulty increase of the mathematical equations of those concepts.

Why use logic?