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[INDENT]"Not distinguishing between deductive arguments, and valid deductive arguments, is just like not distinguishing between addition, and correct addition." (Kennethamy, source)
"A deductive argument is one such that if it is correct, then it is impossible for the premises to be true, and the conclusion false. (Logically impossible). But surely, you see there is a difference between an addition, and a correct addition. Why then is it so difficult to see the difference between a deductive argument, and a correct (valid) deductive argument[?] Just as not all additions are correct, not all deductive arguments are valid.
Just as we use addition to get true answers to sums, so we use deduction to get true conclusions from true premises. And, just as we sometimes fail to get true answers to sums, so we sometime fail to get true conclusions from true premises. [Both] are due to mistakes on the part of the person who does the adding, in the first case; and due to mistakes on the part of the deducer, in the second case. The two are quite parallel." (Kennethamy, source.)
[/INDENT]
The question is if this analogy is apt. I think it has at least a lot of initial plausibility....[but] The analogy is circular. This analogy is very plausible initially but not plausible when one thinks about it carefully....But wait, what kind of arguments are additive arguments? They are deductive arguments! Additive arguments are a proper subset of deductive arguments.
I note that the analogy goes on the level of the act of adding and the act of deducing and not at the level of additive arguments and deductive arguments.
Still that all deductive arguments are valid is something that is denied in pretty much all logic textbooks, but again, textbooks have been wrong in the past.
Fast,
I misspoke in the quote you *quoted* from me. I edited it. Can you do me a favor and delete it or something? Lol! I just don't want to get misinterpreted for making a claim I am not actually claiming--which seems to be the trend adopted by some others in this thread...:a-ok:
Thanks, buddy.
Or something? No problem! :devilish:
Just to expound, deductive arguments have to do with validity (i.e. Is this argument valid/invalid?), and inductive arguments have to do with strength (i.e is this argument weak/strong?)
Notice that with deductive arguments, it's either valid, or it's invalid. There are no matters of degree as is with the strength of inductive arguments.
No valid/invalid argument is weak/strong.
No weak/strong argument is valid/invalid.
All deductive arguments are valid/invalid.
All inductive arguments are weak/strong.
No, fast. I am not saying that.
I make the distinction between what logicians call "formal" and "informal" arguments. And most non-deductive arguments are not "numerative" (or inductive) arguments anyway.
For instance, these are all non-deductive informal kinds of arguments:
(1) Argument by Analogy
(2) Inference to the Best Explanation.
(3) Those arguments using the principle of sufficient reason.
(4) Evidential
(5) Appeal to proper authority
(6) Appeal to Self-Evident First Principles
(7) Pragmatic-style arguments
(8) Appeal to Testimony
(9) Appeal to Empirical and Logical probabilities
etc. etc.,...
the list goes on and on.
The term "inductive" is just sometimes (though probably incorrectly) used to characterize all those arguments that are not deductive (or formal) arguments. But I don't think that should be a problem...whatever distinction you want to make, it only requires that we be able to recognize the difference between validity and strength. That's the difference defining the two classes of arguments.
This is not the same outline as I had envisioned before. With this outline, "inductive" is the superset while the two subsets are 1) enumerative induction (aka inductive generalization) and 2) remaining inductive arguments. If this is the case, then both 1 and 2 are both inductive and non-deductive-even though there are still differences between them.
What I understood before (or thought I understood) was actually more complex. I had thought we were dealing with two different outlines with overlap such that some non-deductive arguments were not inductive, but if you are in fact saying that 1 and 2 above are subsets of induction, then maybe things are simpler than I thought.
The term, I think, is "enumerative induction", not "numerative". It is also known as, "inductive generalization". Hume discussed enumerative induction exclusively during his discussions of the justification of induction, and his influence was so great that enumerative induction that enumerative induction became identified with induction in general. Thus, we needed a term like "non-deductive argument" to cover the rest of what should have been called. "inductive arguments".
This goes to the very heart of what this thread is about. If there's anything that you and Extrain agree on, it seems to be that if an argument is not deductive, then an argument is inductive; moreover, if an argument is not inductive, then an argument is deductive--or so you and he (and I suppose many others) believe.
However, it's that very assumption that I'm questioning. I'm trying to apply what I know about the differences between "invalid" and "not valid" to this issue. It's my understanding that "deductive" and "not deductive" is collectively exhaustive (not to mention "inductive" and "not inductive"), and even though "deductive" and "inductive" may be contrary (and that it's merely contrary is the real confusion), I don't see that "deductive" and "inductive" exhaust all possibilities.
Hence, it's possible to have an argument that is both 1) not deductive and 2) not inductive. An example would be a non-deductive argument that isn't enumerative.
Of course, some people may indeed mean what "not deductive" means when they say, "inductive", but unless the term means what they, themselves mean, it's unimportant. At any rate, I believe it's a legitimate distinction to be made (the distinction between "non-deductive" and "inductive") just as it's legitimate to distinguish between "not valid" and "invalid" (and just as it's legitimate to distinguish between "not true" and "false").
PS: What does DIS mean?
You may be one of those that mean enumeration by
"induction". I don't. "Enumeration" seems to be a good word for that, why use "induction"?
Of course, if we stipulate that "induction" means enumeration, then deductive arguments and inductive arguments do not exhaust all possibilities; there exists an argument that is neither deductive or inductive.
What "DIS" means is irrelevant. The reason I chose it was that "distinction" was too long and it had to be with an important distinction. It's not important.
In any case, I'll write a section explaining my usage of "induction".
PS. You still have not answered what you mean when you write "invalid". For me it is quite simple. I just mean non-valid, an argument that is not valid.
You may be one of those that mean enumeration by
"induction". I don't. "Enumeration" seems to be a good word for that, why use "induction"?
Of course, if we stipulate that "induction" means enumeration, then deductive arguments and inductive arguments do not exhaust all possibilities; there exists an argument that is neither deductive or inductive.
What "DIS" means is irrelevant. The reason I chose it was that "distinction" was too long and it had to be with an important distinction. It's not important.
In any case, I'll write a section explaining my usage of "induction".
PS. You still have not answered what you mean when you write "invalid". For me it is quite simple. I just mean non-valid, an argument that is not valid.
This is not the same outline as I had envisioned before. With this outline, "inductive" is the superset while the two subsets are 1) enumerative induction (aka inductive generalization) and 2) remaining inductive arguments. If this is the case, then both 1 and 2 are both inductive and non-deductive-even though there are still differences between them.
What I understood before (or thought I understood) was actually more complex. I had thought we were dealing with two different outlines with overlap such that some non-deductive arguments were not inductive, but if you are in fact saying that 1 and 2 above are subsets of induction, then maybe things are simpler than I thought.
"Non-valid" no more means "not valid", than does, "non-intelligent" mean "not-intelligent" (or "unintelligent").
These things are easier visually.
http://img442.imageshack.us/img442/651/argumentsdeductiveinduc.jpg
---------- Post added 04-12-2010 at 08:14 PM ----------
"The argument is non-valid." "The argument is not valid." These two mean the same. And I mean the same by the sentence "The argument is invalid." as I mean by the other two. You may not do that. If you don't then your language usage differs my mine in this aspect. I still haven't got an answer for what "invalid" would then mean. I have asked many times.
That may not be analogous with a different word like "intelligent". Words differ in many aspects.
"The person is non-intelligent." I don't take to mean anything.
"The person is not intelligent." I take to be an euphemism for that the person is of lower than average intelligence. Similarly, the sentence "The person is intelligent." means that the person is of above average intelligence. Contrast with "The species is intelligent." which means that members of the species generally posses intelligence.
"The person is unintelligent." (a bit disanalogous because it uses a different negation prefix; -UN instead of -IN) I take to mean that the person is of low intelligence.
PS. You still have not answered what you mean when you write "invalid". For me it is quite simple. I just mean non-valid, an argument that is not valid.
These things are easier visually.
http://img442.imageshack.us/img442/651/argumentsdeductiveinduc.jpg
But it doesn't follow from the fact that you do not choose to recognize a distinction that the distinction does not exist. There is a distinction in English between "disinterested" and "uninterested", but some people, either because they don't know the distinction, or because they refuse to recognize the distinction, use "disinterested" and not "uninterested". But why does that matter? It is the distinction that counts, not the words. I may call all cats "dogs", but cats and dogs are different anyway.
I think it was Charles Pierce that wrote greatly on deduction, induction, and also abduction(?).
An argument that can't possibly be valid can't possibly be invalid.
A deductive argument can possibly be valid, so it can possibly be invalid.
An inductive argument cannot possibly be valid, so it cannot possibly be invalid.
Awesome!
I would say to be very careful with the term, "non-enumerative." You wouldn't want to inadvertently include deductive arguments.