Consider your source. You are not using a professional source. You are using an inferior source. I have heard Emil talk good of Wikipedia, but it's still a poor source.

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.

Actually, some logic books use the term "cogent" to mean, "known to be true", and not just true. So, a cogent argument would be one where the premises are not only true (and argument valid) but are known to be true, so the conclusion is known to be true. But the books differ on this.

Consider your source. You are not using a professional source. You are using an inferior source. I have heard Emil talk good of Wikipedia, but it's still a poor source.

I looked at a couple of more "professional" sources before using the link to Wikipedia, and they did not use the term "cogent" at all in their discussions of induction. If you are going to introduce nonstandard terms, you should explain their meaning, or at least provide a link to such an explanation. Otherwise, you have no right to complain when someone does not know what you are talking about.

I think Wikipedia is a fine source for giving someone a quick idea of what something is about, but I'd rather see a counter argument or good reason for thinking either I'm mistaken or that Wikipedia is correct.

I don't think I get what you're saying, or at least I hope I don't.

I dont know if you guys have answered the Op or not but I'll throw out some ideas on the subject.

Deductive arguments have true premises and a conclusion that necessarily follows. While inductive arguments have conclusions that are probable, but not necessary. So me thinks inductive arguments hinge on logical possibility while deductive arguments dont. So its impossible to have a counter example to a deductive argument. Does that work emil?

I am still a bit puzzled by your questions, particularly coming from you. What is wrong with the responses given in a typical introductory logic textbook?

3. Yes.
4. No, unless you mean that part of a lengthy argument (that is really a series of arguments) is inductive, and part is deductive.

A deductive argument is an argument where the conclusion follows necessarily from the premises.

A valid deductive argument is a deductive argument where the conclusion follows necessarily from the premises.

A non-valid deductive argument is a deductive argument where the conclusion does not follow necessarily from the premises.

An inductive argument is an argument where the premises offer a degree of support for the conclusion, but do not necessarily entail it; there is no guarentee (like your article noted).

I think it depends how we use the word "argument". But, I think if we use the word formally, the answer is yes.

Do you see how many ways this question can be interpreted?

1.) Yes, some arguments are deductive, some arguments are inductive.
2.) Yes, some arguments (like Pyrrho noted), can have inductive and deductive parts.
3.) No, if you mean that only some arguments are inductive or deductive. Because all formal arguments are deductive or inductive (and you might mean this since this question comes after the one which specifies "all arguments").

That is not difficult. Deductive arguments are intended to be conclusive arguments by the arguer. If the argument is not conclusive, but is intended to be conclusive, it is a failed (invalid) deductive argument. On the other hand, if an argument is not intended to be a conclusive argument by the arguer, it is non-deductive. But if the premises fail to support the conclusion of the non-deductive argument, then it is a failed (weak) non-deductive argument.

However, whatever the arguer intends, deductive or non-deductive, there are some arguments which it would hardly make sense to intend it as deductive, since it is so clearly non-conclusive; or make sense to intend it as non-deductive since it is so clearly conclusive. It would be a good rule (I think) to count a valid deductive argument as deductive, and a strong non-deductive argument as non-deductive.

But can't we distinguish between inductive and deductive arguments without considering the intent of the arguer at all?

I don't see how, although, as I said, there are pretty clear cases of both kind when it would be implausible for the arguer's intention not to be the one or the other. In those cases we have what, in legal jargon, we might call, "constructive intent". That it was the arguer's intent whether or not it actually was (or the arguer was confused).

But we can distinguish an inductive argument from a deductive argument by looking looking at the argument. If all the premises can be true without the conclusion being true, it is an inductive argument:

1.) Socrates was Greek
2.) Most Greeks eat fish
3.) Socrates ate fish

This is an inductive argument. And we know it's not a deductive argument because although the premises may be true, the conclusion does not follow necessarily from the premises; the conclusion may not be true.

Isn't that right?

I would rather say, we do not know what the argument is without knowing the intentions of the arguer. But once we know what the argument is, we then may be able to determine whether it is deductively valid or not, and whether it is inductively valid or not.

Perhaps, though, this is a mere verbal distinction, without any importance at all.

Emil,

I thought what you were meaning to ask for is an analysis of deductive arguments and/or an analysis of inductive arguments. You already know the difference between the two, so you do not need an explanation of what each is. Instead, what you want is an analysis, for merely knowing the difference between the two doesn't therefore imply that you can always be given an argument and definitively determine whether or not the logical argument is a deductive argument or inductive argument, for sometimes, being privy to the argument is insufficient information to determine whether or not an argument is deductive or inductive.

That of course has no bearing on whether or the argument is deductive or inductive, just as truth doesn't depend on knowledge of the truth.

I don't think you should ever regard inductive arguments as valid or invalid.

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?

No arguments are either true or false. Are you, perhaps asking whether a valid argument must have a true conclusion. The answer is, no. The same for whether a valid argument must have true premises. But, what is true is that any valid argument with true premises must have a true conclusion.

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.

Right, because premises and conclusions are propositions (statements) and only propositions (statements) are true or false.

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.

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.

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.

Actually, some logic books use the term "cogent" to mean, "known to be true", and not just true. So, a cogent argument would be one where the premises are not only true (and argument valid) but are known to be true, so the conclusion is known to be true. But the books differ on this.

What is a valid inductive argument anyway?

I dont know if you guys have answered the Op or not but I'll throw out some ideas on the subject.

Deductive arguments have true premises and a conclusion that necessarily follows. While inductive arguments have conclusions that are probable, but not necessary. So me thinks inductive arguments hinge on logical possibility while deductive arguments dont. So its impossible to have a counter example to a deductive argument. Does that work emil?

According to the validity theory, all deductive arguments are valid and all inductive arguments are invalid.

T

Careful. Do you accept Ken's view (=intention theory)? If so, then some inductive arguments are valid, because some arguments are intended by the speaker to be inductive but are actually valid.



.

I might agree that inductive arguments are not valid, but from that, I am not inclined to believe that inductive arguments are invalid.

Invalid = not valid.

I said that if an argument is valid, then we should count it as a deductive argument even if the arguer intends it to be inductive (or thinks it is inductive). Two reasons: 1. It is neater this way. 2. It follows from the principle of charity.

Invalid = not valid.

Invalid implies not valid, but not valid doesn't imply invalid, so invalid does not equal not valid.

I think fast means that to call inductive arguments invalid is a category mistake. I think that is right.

This is inconsistent with the intention theory. You would have to make up some clause to remove this inconsistency. I have not found any way to do this.

The principle of charity is only a general maxim that is in general useful to follow.

Easy. "except when the argument is valid". That supersedes the intention of the arguer. It is generally useful to follow the principle of charity in this case.

But then the theory is lacking an explanation for this case, otherwise it is special pleading. The theory goes like this: [INDENT]An argument is inductive iff the arguer intended for it to be inductive, except when it is valid, then it is deductive.
[/INDENT]Why does the opposite and analogous exception clause not hold too then?: [INDENT]An argument is deductive iff the arguer intended for it to be deductive, except when it is invalid, then it is inductive.
[/INDENT]Even though it may be useful to see arguments that are intended as inductive, as deductive, they are not deductive according to the definition in that theory. And what is needed is a definition not a general maxim or rule.