# What is the usefulness of formal logic theory?

• B
What exactly is the usefulness of formal logic theory?

And how much useful is it?

I believe that most of us have an intuitive sense of logic, which has to be very useful throughout our lives and just about for every situation we can think of. Given that, I came to wonder what more does formal logic specifically brings to the table?
Obviously, having a formal language to express the more complicated logical relations is very useful, even necessary nowadays with the development of technology and science, but beyond instances of using the formalism of formal logic, could anybody give practical examples of using formal logic theory to solve a problem in the real world? Something useful!
And I would exclude from that maths research, not because I think it's hopelessly useless, but because I need to understand how logic theory is useful and I need to understand that here and now. So, using logic theory to help with applied maths would be OK, too. That is, if logic theory is used to sort out a maths problem meant to model some real-world situation, in which case logic theory would be useful to help with useful maths, and that would be obviously useful.
I'm really only interested in First Order Logic, but Second Order examples should also be of interest.
Thanks,
EB

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fresh_42
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What exactly is the usefulness of formal logic theory?

And how much useful is it?

I believe that most of us have an intuitive sense of logic, which has to be very useful throughout our lives and just about for every situation we can think of. Given that, I came to wonder what more does formal logic specifically brings to the table?
This is as if you asked, why to define a meter. Close, near, far and astronomic far cover all what we need.
And I would exclude from that maths research, not because I think it's hopelessly useless, but because I need to understand how logic theory is useful and I need to understand that here and now. So, using logic theory to help with applied maths would be OK, too. That is, if logic theory is used to sort out a maths problem meant to model some real-world situation, in which case logic theory would be useful to help with useful maths, and that would be obviously useful.
I have severe problems with what you call useful. This is a short sighted and highly subjective term which hasn't any scientific relevance. Take the zero, e.g. Why did people start to count something, which isn't there? That's why I consider the word useful as a biased, purely rhetoric term without any substance, except to start a fruitless dispute. What you call useful logic, is merely one possible logic system. The usefulness of all other, and there are various, is restricted by our current limitation, not by the number of potential alternatives. But even the predicate logic in use appears quite often rather alienated, esp. in interviews of politicians.

So logic is important, because it measures scientific fields and helps to distinguish between valid and absurd theories. Same as the meter is.

This discussion is already philosophy, because it basically asks about the usefulness of science - logic is just a placeholder here. A sujet, which has been discussed before, on PF as well, please make a forums search, and probably will be discussed on many other occasions and places. There is no final answer to this by the setting of the question, and any answer heavily depends on personal scales.

So if you don't have a specific source from a valid scientific publication, in which case you're invited to send me a PM with a reference, this thread is closed. Reason: no defined end of debate.

Evo and Greg Bernhardt