Philosophy Now Forum

It seems to me that logic is decidedly useless in philosophy. It would seem to have achieved nothing. The only reason it is considered in philosophy is because of its claim to truth which is summed up in the statement " This statement is true." Which is a quite meaningless statement.

I think that if all that has been written on the conflation of logic, truth and statements were consigned to Hume's flames, philosophy would be the better for it.

The achievements include conceptual clarity, understanding inference and implication, making sense versus uttering nonsense that doesn't follow from anything . . . maybe you don't value those things though.

Terrapin Station wrote:The achievements include conceptual clarity, understanding inference and implication, making sense versus uttering nonsense that doesn't follow from anything . . . maybe you don't value those things though.

Those things come from common sense and clear thinking rather than logic per se. They hardly constitute achievements of logic. Have you got anything else?

A_Seagull wrote:

Terrapin Station wrote:The achievements include conceptual clarity, understanding inference and implication, making sense versus uttering nonsense that doesn't follow from anything . . . maybe you don't value those things though.

Those things come from common sense and clear thinking rather than logic per se. They hardly constitute achievements of logic. Have you got anything else?

Logic is "the laws of thought." In other words, clear thinking about inference/implication etc. IS logic.

Terrapin Station wrote:

A_Seagull wrote:

Terrapin Station wrote:The achievements include conceptual clarity, understanding inference and implication, making sense versus uttering nonsense that doesn't follow from anything . . . maybe you don't value those things though.

Those things come from common sense and clear thinking rather than logic per se. They hardly constitute achievements of logic. Have you got anything else?

Logic is "the laws of thought." In other words, clear thinking about inference/implication etc. IS logic.

No it isn't. Clear thinking and sensible inference existed long before logic was invented. Logic may be the study of clear thinking and sensible inference, but that is different. Which brings me back to my original question: What has logic achieved?

A_Seagull wrote:

Terrapin Station wrote:

A_Seagull wrote:
Those things come from common sense and clear thinking rather than logic per se. They hardly constitute achievements of logic. Have you got anything else?

Logic is "the laws of thought." In other words, clear thinking about inference/implication etc. IS logic.

No it isn't. Clear thinking and sensible inference existed long before logic was invented. Logic may be the study of clear thinking and sensible inference, but that is different. Which brings me back to my original question: What has logic achieved?

What do you take to be the evidence of logic being invented rather than being a way that we naturally think?

A_Seagull wrote:It seems to me that logic is decidedly useless in philosophy. It would seem to have achieved nothing. The only reason it is considered in philosophy is because of its claim to truth which is summed up in the statement " This statement is true." Which is a quite meaningless statement.

I think that if all that has been written on the conflation of logic, truth and statements were consigned to Hume's flames, philosophy would be the better for it.

Logic is a vague word, ironic isn't it? Some people may say that I'm writing in a product of logic.

I'm inclined to agree, Seagull. Most syllogisms seem to pertain to plays on words or expressing what is clear from use of commonsense.

Many in philosophy deride commonsense because there are so many instances where our senses fool us. IMO the baby went out with the bathwater. When considering any issue, in the first instance I'll go for the basic obvious perceptions of Ms and Mr Average. If that fails, then I can research scientific findings. That that approach fails, then I use logic.

The greatest failure of "commonsense thinking" is the frequent taking of phenomena for granted. We naturally simplify real things down to sketchy abstractions so we can make sense of them. Commonsense fails to make sense if we forget that the abstractions of our perceptions and paradigms are just a sketch, not the reality. Or, as Leo would say, we confuse "the map for the territory".

A_Seagull wrote:It seems to me that logic is decidedly useless in philosophy. It would seem to have achieved nothing. ...

Grounded and helped clarify the foundations of Mathematics and produced the study of Formal Axiomatic Systems.

Helps out in Phil of Language which helps out in the NLP computing world, also in the computing depts with security and admin issues with operating systems.

The practice of it helps identify invalid arguments. It also helps construct valid ones.

Historically it has been one of the legs of Philosophy.

Helped out Spinoza and Russell and Wittgenstein and C.S.Pierce and Leibniz with their thoughts.

I take your point but think it actually Philosophy with applications all over the place. But I suppose it depends what you think Philosophy is, if it's Metaphysics and such like then no, its not that useful other than pointing out contradictions in thought.

A_Seagull wrote:It seems to me that logic is decidedly useless in philosophy. It would seem to have achieved nothing.

It's not really the aim of philosophical logic to achieve anything; its purpose is simply to determine whether arguments are valid on not.

A_Seagull wrote:The only reason it is considered in philosophy is because of its claim to truth which is summed up in the statement " This statement is true." Which is a quite meaningless statement.

Again, that is not what logic is about. 'Truth' doesn't enter into it; that's for science to decide.

A_Seagull wrote:I think that if all that has been written on the conflation of logic, truth and statements were consigned to Hume's flames, philosophy would be the better for it.

There are plenty of people, who spout incoherent nonsense and call it philosophy, that would agree with you.
Hume was a brutally logical thinker. By flames, I presume you are referring to this from An Enquiry Concerning Human Understanding:
"If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion."

uwot wrote:

A_Seagull wrote:It seems to me that logic is decidedly useless in philosophy. It would seem to have achieved nothing.

It's not really the aim of philosophical logic to achieve anything; its purpose is simply to determine whether arguments are valid on not.

And how does it do that? Is your argument 'valid"?

A_Seagull wrote:The only reason it is considered in philosophy is because of its claim to truth which is summed up in the statement " This statement is true." Which is a quite meaningless statement.

Again, that is not what logic is about. 'Truth' doesn't enter into it; that's for science to decide.

So how come that logic asserts that every statement is either true or false??

A_Seagull wrote:I think that if all that has been written on the conflation of logic, truth and statements were consigned to Hume's flames, philosophy would be the better for it.

There are plenty of people, who spout incoherent nonsense and call it philosophy, that would agree with you.

And probably even more who would disagree!

Hume was a brutally logical thinker. By flames, I presume you are referring to this from An Enquiry Concerning Human Understanding:
"If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion."

Perhaps there is confusion, when I used the word 'logic' in the OP I was not referring to logical and clear thinking; I was referring to syllogisms, so called laws of logic and formal logic. And yes I think that those instances of philosophy fail Hume's fork.

A_Seagull wrote:...
Perhaps there is confusion, when I used the word 'logic' in the OP I was not referring to logical and clear thinking; I was referring to syllogisms, so called laws of logic and formal logic. ...

But these are examples of logical thinking?

Why do you think the laws of logic are so-called?

And yes I think that those instances of philosophy fail Hume's fork.

Except his fork was about theology and metaphysics and Logic does discuss appear to discuss fact and existence as it marks the boundaries of what is impossible, necessary and contingent.

A_Seagull wrote:And how does it do that?

Depends on the logic you are using, but generally by comparing the structure of arguments with certain recognised patterns.

A_Seagull wrote:Is your argument 'valid"?

It's more a description than an argument.

A_Seagull wrote:So how come that logic asserts that every statement is either true or false??

Where does it do that? (Truth tables are something else.)

A_Seagull wrote:Perhaps there is confusion, when I used the word 'logic' in the OP I was not referring to logical and clear thinking; I was referring to syllogisms, so called laws of logic and formal logic. And yes I think that those instances of philosophy fail Hume's fork.

No confusion. Syllogisms, so called laws of logic and formal logic are to philosophers a bit like scales are to a musician, the more you practise them, the better you can play your instrument. Logic is a core subject in any half decent undergraduate philosophy course.
Hume's fork is basically his division of relations of ideas and matters of fact; in effect rationalism and empiricism; which Kant tried to synthesise.

A_Seagull wrote:So how come that logic asserts that every statement is either true or false??

It doesn't. Not all logic is bivalent logic. Not all logic features the law of excluded middle. If you're going to make sweeping statements about what logic does or doesn't do, at least be familiar with it.

A_Seagull wrote:It seems to me that logic is decidedly useless in philosophy. It would seem to have achieved nothing. The only reason it is considered in philosophy is because of its claim to truth which is summed up in the statement " This statement is true." Which is a quite meaningless statement.

I think that if all that has been written on the conflation of logic, truth and statements were consigned to Hume's flames, philosophy would be the better for it.

This is completely odd to me. I'm disappointed how much most don't know that this is an art and science of reasoning. It is actually the PARENT to all philosophical (intellectual) inquiry.

"Logic" derives from "log" (a record) and/or "look". "Science" also derives from a word meaning "to see".

Words ending in "-ogic" refer to mean "the (formal) study of"


LOGIC is the generalized process of reasoning to ALL subjects of intellectual inquiry. It is also a prerequisite to philosophical analysis and debate.

All maths are logic that use numbers as the 'variables' and constant truths used. A calculator is literally the physical form of a complex logic that uses real electronics to replace the intellectual symbols. Grammar is the logic of a particular language, like a high-ordered computer language. (Note that all computers are just extended calculators and so is all about logic.

Our neurons operate on a 'logic' unique to living things.

Basically, logic(s) deal with how to CONNECT separate data into complex ones OR to determine those simple ones from the complex. What is most important is to make an 'argument' such that IF the inputs are ASSUMED 'true', then the conclusion MUST be 'true' and 'follow' as well.