Need expert advice on how to handle a seemingly legitimate objection

[fast]

What I need from you, the reader: I need you to lay aside your beliefs and presume that what I say is correct. You don't have to believe me, and you certainly don't need to point out sources that portray my position to be in error. I need you to treat what I say as fact and to the best of your ability help me overcome an objection that leaves me searching for straws.

Just as false implies not true, invalid implies not valid, yet just as not true doesn't imply false, not valid doesn't imply invalid.

The objection: invalid means not valid

Eta: read post#5 for added clarity

 

[Kharakov]

Go get me a sammich. <- not true or false. No categorization as either for an imperative statement.

I like coffee. <-- true, but it isn't an argument, so it is neither valid nor invalid.

Rememember: not false does not imply true. Not valid does not imply validity.

Statements have to be arguments of a certain form to be valid or invalid. Commands (or imperative statements) do not have truth value- so are neither true nor false.

 

[bilby]

Invalid always means not valid; but not valid doesn't always mean invalid.

Sheep always means mammal; but mammal doesn't always mean sheep.

Your objection presents a false dichotomy.

 

[Kharakov]

Why didn't you say something witty and entertaining?

 

[fast]

If something is a logical argument, then it's either a deductive argument or a non-deductive argument. Some non-deductive arguments are inductive arguments, and some non-deductive arguments are not inductive arguments. Either way, no non-deductive argument is the kind of argument than can be valid or invalid. Only deductive arguments are the kind of arguments that can be valid or invalid.

However, some believe that I'm incorrect and hold the belief that inductive arguments are the kinds of arguments that can correctly be regarded as invalid arguments (and they're wrong), but they hold this belief in part because they believe inductive arguments are not valid arguments--and they are correct.

The error they are making is in believing that inductive arguments are the kinds of arguments that can be invalid. Sure, all inductive arguments are arguments that are not valid, but I deny that these arguments that are not valid are therefore invalid arguments.

When we speak of an argument as invalid, it's not necessarily identical to speaking of an argument as not valid. We are saying more than some realize when we speak of an argument as invalid than if we simply spoke of an argument as not valid. To say that an argument is not valid, we're merely saying that it's an argument and that it's not valid, but to say of an argument that it's invalid says more--it's saying that it's the kind of argument that can be valid.

Recall, i hold the view that non-deductive arguments (and thus inductive arguments and non-deductive/non-inductive arguments) are not even the kinds of argument that can be valid. It's what you might call a category error.

Anyhow, none of that is open for your dispute even should you think I'm in error. The heart of the matter has much (much, I say) more to do with the objection.

 

[Togo]

Whether or not 'not valid' means invalid depends on whether it is reasonable to expect an argument to be valid in the first place.

For arguments that should be valid, that they aren't is a serious object, and such arguments are invalid arguments.

For arguments where validity isn't a primary concern, a lack of validity is not a particular concern, and thus not valid doesn't mean the argument is invalid.

So it comes down to whether an argument should be reasonably expected to be valid. You're arguing that there is a category that shouldn't. That seems like an entirely reasonable approach, although obviously some people will disagree as to whether this category really exists.

 

[fast]

I agree, but there's more. Gotta run at moment. I can overcome objections if I'm dealing with technical (or stipulative) definitions, but there's something I'm after regarding lexical definitions that I think can be done, and although I have very firm convictions regarding meaning, they are causing issues I'm not quite sure how to handle. Will be back in many hours...life.

 

[jonatha]

Why doesn't "not true" imply false?

It certainly does if you're dealing with normal truth tables...

 

[fast]

Why doesn't "not true" imply false?

It certainly does if you're dealing with normal truth tables...

If a declarative sentence expresses a proposition, then the proposition is either true or not true. Likewise, if a declarative sentence expresses a proposition, then the proposition is either true or false. In fact, if a declarative sentence expresses a false proposition, then the proposition is not true. Furthermore, if a declarative sentence expresses a proposition that is not true, then the proposition is false.

The problem arises not with declarative sentences that express propositions. The problem arises with sentences that do not express propositions. No such sentence is true, and no such sentence is false. Such sentences are neither true nor false. Hence, they are not true and not false.

Examples:
1) some people eat healthier than others: true
2) all people smoke pot: not true, false
3) orange eats seven: not true, not false

 

[jonatha]

Does the problem resolve itself if you arbitrarily define your third category to be false?

 

[Speakpigeon]

It was apparently de Morgan in 1847 who coined the term "universe of discourse". Working on a theory of logic, de Morgan was trying to specify what we thought about when using the negation. I can oppose vertebrate to invertebrate if I limit myself to the animals. I wouldn't qualify a star, a theorem or a tennis match as invertebrate. In this case the universe of discourse contains only animals, not the universal class (everything) as Boole was doing at the same time.
EB

 

[Speakpigeon]

I would reword the objection: invalid means the same as not valid.

And I disagree with it. Words and linguistic expressions don't mean anything by themselves. We mean something when we use them. And, we may mean different things with the same expression according to the context. First, the context of the sentence, i.e. what other words come in. And also the context of situation, i.e. who I am talking with etc.

That being said, we usually mean the same thing by invalid and not valid, certainly when applied to arguments. In this context, we nearly always mean the same thing with these two terms.
EB

 

[fast]

Does the problem resolve itself if you arbitrarily define your third category to be false?

The thing to remember is that "not true" is substantially more inclusive whereas "false" only applies to that which can be false.

 

[fast]

I would reword the objection: invalid means the same as not valid.

And I disagree with it. Words and linguistic expressions don't mean anything by themselves. We mean something when we use them. And, we may mean different things with the same expression according to the context. First, the context of the sentence, i.e. what other words come in. And also the context of situation, i.e. who I am talking with etc.

That being said, we usually mean the same thing by invalid and not valid, certainly when applied to arguments. In this context, we nearly always mean the same thing with these two terms.
EB

When speaking about deductive arguments, we do effectively mean the same thing by "invalid" as we do "not valid", and it makes sense that there would be a lexical definition of "invalid" to mean not valid, but doesn't the technical term, "invalid" have a stipulative meaning that means more? For instance, in your example, clearly any animal that is an invertebrate is an animal that is not a vertebrate, but no star is the kind of thing that can be either a vertebrate or invertebrate, yet it's still not a vertebrate ... And if I'm right that no non-deductive argument is the kind of thing that be either valid or invalid, then it's false to say non-arguments are invalid yet true to say they are not valid arguments, so even if it's true that the terms nearly always mean the same when discussing deductive arguments, they do not (as you say) nearly always mean the same thing--since they never nearly always mean the same when applied, as evidenced when they are applied to non-deductive arguments.

 

[steve_bnk]

What I need from you, the reader: I need you to lay aside your beliefs and presume that what I say is correct. You don't have to believe me, and you certainly don't need to point out sources that portray my position to be in error. I need you to treat what I say as fact and to the best of your ability help me overcome an objection that leaves me searching for straws.

Just as false implies not true, invalid implies not valid, yet just as not true doesn't imply false, not valid doesn't imply invalid.

The objection: invalid means not valid

Eta: read post#5 for added clarity

If this is the kind of perplexingthoughts you have, how can you possibly read a book or function atall in society.


It would all be an uninterpretablejumble.

 

[fast]

What I need from you, the reader: I need you to lay aside your beliefs and presume that what I say is correct. You don't have to believe me, and you certainly don't need to point out sources that portray my position to be in error. I need you to treat what I say as fact and to the best of your ability help me overcome an objection that leaves me searching for straws.

Just as false implies not true, invalid implies not valid, yet just as not true doesn't imply false, not valid doesn't imply invalid.

The objection: invalid means not valid

Eta: read post#5 for added clarity

If this is the kind of perplexingthoughts you have, how can you possibly read a book or function atall in society.


It would all be an uninterpretablejumble.

With all the women in my life, I neither the time to read nor function properly.

 

[steve_bnk]

What I need from you, the reader: I need you to lay aside your beliefs and presume that what I say is correct. You don't have to believe me, and you certainly don't need to point out sources that portray my position to be in error. I need you to treat what I say as fact and to the best of your ability help me overcome an objection that leaves me searching for straws.

Just as false implies not true, invalid implies not valid, yet just as not true doesn't imply false, not valid doesn't imply invalid.

The objection: invalid means not valid

Eta: read post#5 for added clarity

If this is the kind of perplexingthoughts you have, how can you possibly read a book or function atall in society.


It would all be an uninterpretablejumble.

With all the women in my life, I neither the time to read nor function properly.

I am sure you are the srtudliest of studly studs, but that has nothing to with your assertions.

if you believe up is really down and forwards is really backwards you will have a hard time navigating reality. Likewise if you try to insist logical contentions are false then you can never communicate.

 

[fast]

What I need from you, the reader: I need you to lay aside your beliefs and presume that what I say is correct. You don't have to believe me, and you certainly don't need to point out sources that portray my position to be in error. I need you to treat what I say as fact and to the best of your ability help me overcome an objection that leaves me searching for straws.

Just as false implies not true, invalid implies not valid, yet just as not true doesn't imply false, not valid doesn't imply invalid.

The objection: invalid means not valid

Eta: read post#5 for added clarity

If this is the kind of perplexingthoughts you have, how can you possibly read a book or function atall in society.


It would all be an uninterpretablejumble.

With all the women in my life, I neither the time to read nor function properly.

I am sure you are the srtudliest of studly studs, but that has nothing to with your assertions.

if you believe up is really down and forwards is really backwards you will have a hard time navigating reality. Likewise if you try to insist logical contentions are false then you can never communicate.

What are you talking about? Declarative sentences that fail to express a proposition are neither true nor false. Again, they are both not true and not false. Not true? Yes. False? No. Just because the sentence is not true, it is not therefore false.

 

[steve_bnk]

What I need from you, the reader: I need you to lay aside your beliefs and presume that what I say is correct. You don't have to believe me, and you certainly don't need to point out sources that portray my position to be in error. I need you to treat what I say as fact and to the best of your ability help me overcome an objection that leaves me searching for straws.

Just as false implies not true, invalid implies not valid, yet just as not true doesn't imply false, not valid doesn't imply invalid.

The objection: invalid means not valid

Eta: read post#5 for added clarity

If this is the kind of perplexingthoughts you have, how can you possibly read a book or function atall in society.


It would all be an uninterpretablejumble.

With all the women in my life, I neither the time to read nor function properly.

I am sure you are the srtudliest of studly studs, but that has nothing to with your assertions.

if you believe up is really down and forwards is really backwards you will have a hard time navigating reality. Likewise if you try to insist logical contentions are false then you can never communicate.

What are you talking about? Declarative sentences that fail to express a proposition are neither true nor false. Again, they are both not true and not false. Not true? Yes. False? No. Just because the sentence is not true, it is not therefore false.

HEEHEE

'...Just as false implies not true, invalid implies not valid, yet just as not true doesn't imply false, not valid doesn't imply invalid...'

My first impulse is to say your argument not invalid, however as you point out not valid does not infer invalid at all....

Your op kinda sounds like nonsense philosophical babble does it not?

 

[fast]

What I need from you, the reader: I need you to lay aside your beliefs and presume that what I say is correct. You don't have to believe me, and you certainly don't need to point out sources that portray my position to be in error. I need you to treat what I say as fact and to the best of your ability help me overcome an objection that leaves me searching for straws.

Just as false implies not true, invalid implies not valid, yet just as not true doesn't imply false, not valid doesn't imply invalid.

The objection: invalid means not valid

Eta: read post#5 for added clarity

If this is the kind of perplexingthoughts you have, how can you possibly read a book or function atall in society.


It would all be an uninterpretablejumble.

With all the women in my life, I neither the time to read nor function properly.

I am sure you are the srtudliest of studly studs, but that has nothing to with your assertions.

if you believe up is really down and forwards is really backwards you will have a hard time navigating reality. Likewise if you try to insist logical contentions are false then you can never communicate.

What are you talking about? Declarative sentences that fail to express a proposition are neither true nor false. Again, they are both not true and not false. Not true? Yes. False? No. Just because the sentence is not true, it is not therefore false.

HEEHEE

'...Just as false implies not true, invalid implies not valid, yet just as not true doesn't imply false, not valid doesn't imply invalid...'

My first impulse is to say your argument not invalid, however as you point out not valid does not infer invalid at all....

Your op kinda sounds like nonsense philosophical babble does it not?

If an argument is deductive, then yes, if it's not valid, then it's invalid, but if an argument isn't deductive, and if they can be neither, then it can't be invalid...yet still be both not valid and not invalid.