Gooch's dad

In a chat debate last week, some fundy pulled the typical tactic along the lines of 'you're using logic, and how do you know logic is valid?'

My reply was roughly 'you are using logic simply by using language, and therefore you're using logic to argue against logic'

But I had a bit of a tougher time defending this. It is obvious that language has rules, such as subject-object and verb usage. Can these rules be said to correspond and imply some of the basic rules of logic?

Which part of language implies that A=A, and which implies that A=/= not-A?

Then there is deduction and induction, and a whole bunch more that I'm leaving out.

Any books to recommend on this topic?

Thanks,

-Kelly

WJ

Kelly,

I think the short answer is yes. But (and that's big but), take a look at Schopenhour's (sp) voluntarism, ethics and metaphysics, or any existentialist and psychologist. Language is a tool to communicate feeling.

That is probably at the root of your opponent's argument. Otherwise, come join us in the Koy...thread as we are encroaching on that very same topic via William James.

EDIT; Oops, forgot to mention a thing called assertoric sentences, but not excatly sure if it is relevent to your here:

<a href="http://www.house-church.net/mt019.htm" target="_blank">http://www.house-church.net/mt019.htm</a>

[ July 16, 2002: Message edited by: WJ ]</p>

owleye

Logic is a language that adheres to rules. To the extent that natural language adheres to rules I suspect it too is logical. The question then becomes whether language must always be adhering to one rule or another. Despite Schopenhauer, I think the answer is yes, particularaly if language is intended to communicate, since, I think, communication requires following rules. With respect to language as a means of expressing thoughts, I would first note that thoughts deal with concepts which have a certain structure to them, and any common structure would likely be expressed in language by a rule. As communication and expression seem to exhaust the functions of language, I would conclude that language must have a logical basis.

owleye

Keith Russell

Greetings:

Logic is self-validating. You can't 'prove' logic, since that would require using something besides logic to establish that proof--and logic alone makes proof possible.

This is akin to asking someone to 'prove' reality. Reality, too, makes proof possible, and thus reality cannot itself be proven.

The evidence required for proof has to be independent of the claim. So, if one were attempting to prove reality or logic, the evidence would have to come from outside reality, outside logic.

There is nothing outside of reality; what isn't 'within' reality isn't...real.

But both reality and logic are self-validating; one must affirm their existence and validity, even to claim that they are invalid.

To ask for 'proof'--even 'proof' of logic, is to voice acceptance of the fact that 'proof' is a valid concept, thus to affirm logic works.

Keith Russell.

TooBad

Two mutually contradictory statements cannot both be true.
Without this assumption, communication is impossible, and all assertions are strictly and literally meaningless. We reaffirm the fundamental principle of logic every day, merely by understanding each other.

WJ

But reality is not logical.

How do we resolve this? Think consciousness and matter.

Gooch's dad

Excellent points, both Keith and TooBad. I've used versions of that same argument myself, Keith.

I suppose someone would say in reply to TB's argument "I can say the sky is up and the sky is not up, and you understood me in both cases, so is language really dependent on the law of non-contradiction?'.

And I guess I would answer that the person can't assert both truths at the same time and still be communicating. So it gets onto the subject of 'assertoric' statements, as WJ said.

So, WJ, what about consciousness and matter are inherently illogical?

Thanks,

Kelly

John Page

Try doing a global search and replace on the above putting "god" instead of "logic" and "reality". Not much help to Gooch's Dad.

Some systems of logic may be internally consistent, but self validating - I don't think so.

Evidence, gentlepeople, is what we need. Reality (or something we call reality) can be proven by experience and other evidence of our existence in it. Self validation not required.

As to language and logic, these are used to describe reality in informational form. Neither are proof in themselves but they can help us communicate about reality. Its just that fundies standards of proof are generally unquestioning - maybe its the human equivalent of where they put a chicken's eye on a white line and it cannot thereafter volutarily move.

Cheers, John

John Page

Sea Lion:

How about revising your statement to:

"The behavior of reality does not necessarily conform to the dictates of systems of formal logic"?

Cheers, John

Clutch

GD, I dunno how much sense it makes to say that language *implies* logic. (ie, implication is itself a logical notion... so you can see where that's going...)

What is correct, by definition no less, is that *reasoning* is characterized by logic. Logic in the general sense just means something like "canons of reasoning that preserve truth across inference". (And then in the specific sense, you can have different logics for different kinds of discourses: intuitionist, quantum, classical, modal, epistemic... whatever.)

So the thing to say to your interlocutor is this: First, he doesn't know what "valid" means, or he doesn't know what logic is. Logic is the science of valid reasoning. And validity is truth-preservation by definition. The worry can't be that maybe truth-preserving inferences aren't truth-preserving -- it must be something like, Maybe, for all we know, what we think is valid isn't. And that is an astonishing bit of buffoonery as a defense of theism. One might as well say, "Well, we might be wrong about anything -- so how can you say the moon isn't a big pickle?"

The shorter reply, of course, is to ask the fundy to frame his point in the form of an argument.

[ July 16, 2002: Message edited by: Clutch ]</p>