I got soundness and validity confused. Validity speaks nothing of truth, only form. To be valid means that the conclusion follows from the premises. An argument being valid does not mean that it is true. Validity is a necessary but not sufficient condition for soundness. It is not a sufficient condition because an argument not only needs to be valid to be sound, but it also needs to be true.

Is this right?

Are you, perhaps asking whether a valid argument must have a true conclusion. The answer is, no.

An argument being valid does not mean that it is true

But, what is true is that any valid argument with true premises must have a true conclusion.

No arguments are either true or false.

My yeah still applies to what he said before he edited.

Validity is a necessary but not sufficient condition for soundness. It is not a sufficient condition because an argument not only needs to be valid to be sound, but it also needs to be true.

No, I'm not asking that. I just told you explicitly the opposite. See here:





Right. Gotcha.



Ah, arguments cannot be said to be true or false, just valid or sound, right? Premises and conclusions are what we apply the properties true and false to.

So you disagree with this? (this is the part I edited in)

As I recall, I agreed with everything you said before you edited. He is right; arguments are not true or false.

Oh, I see now. What I meant to say is that the premises and conclusion within the argument have to be true.

Why would that be? Have to be true so that what? All the statements in the argument may be true, and the argument may be either valid, or invalid.

I was speaking about soundness.

Validity is a necessary but not sufficient condition for soundness. It is not a sufficient condition because an argument not only needs to be valid to be sound, but the premises and conclusion within the argument also need to be true.

A necessary condition for a sound argument is not that the conclusion be true, although, if an argument is sound, then the conclusion will be true. Truth, then, is a consequent of soundness.

We use the terms, "valid", "invalid", "sound," and "unsound" to describe deductive arguments.

We use the terms, "weak," "strong", "cogent", and "not cogent" to describe inductive arguments.

I got soundness and validity confused. Validity speaks nothing of truth, only form. To be valid means that the conclusion follows from the premises. An argument being valid does not mean that it is true. [emphasis added] Validity is a necessary but not sufficient condition for soundness. It is not a sufficient condition because an argument not only needs to be valid to be sound, but it also needs to be true. [emphasis added]

Is this right?

I think people have gotten confused about what you mean because of your statements about arguments being true, which is not a good way of speaking.

Pyrrho;120255 wrote:

It would appear that "cogent" and "strong" mean the same thing, [...].

All cogent arguments are strong arguments, but not all strong arguments are cogent arguments, for all cogent arguments are strong arguments with true premises, and not all strong arguments have true premises.

An argument is cogent if and only if the truth of the argument's premises would render the truth of the conclusion probable.

Who are "we"? But more seriously, the terms for induction are not standardized, and the terms do not line up between deductive and inductive arguments (i.e., although "valid" may be analogous to "cogent", there is no analog for soundness in induction, at least among the terms you have used, according to the links below).

From looking at:

Inductive reasoning - Wikipedia, the free encyclopedia

Cogency - Wikipedia, the free encyclopedia

It would appear that "cogent" and "strong" mean the same thing, and, presumably, "weak" and "not cogent" would also mean the same thing.

---------- Post added 01-15-2010 at 04:11 PM ----------



Not quite, though I think what you might mean is correct. Statements are things that may be true or false, not arguments. Arguments may be valid or invalid, sound or unsound. You appear to have the right idea about valid (though your formulation seems a bit ambiguous). To be sound means that the argument is deductively valid and all of its premises are true. Thus, its conclusion will be true, because, to be valid, the conclusion must follow from the premises.

I think people have gotten confused about what you mean because of your statements about arguments being true, which is not a good way of speaking.

That is not what it says at Wikipedia:

Cogency - Wikipedia, the free encyclopedia

You may use the term differently, but this only reinforces my point that the terms used to describe various inductive arguments are not very standardized.