4. What are the two formal fallacies?

Question: 4!. What are the two formal fallacies!?
Best Answer - Chosen by Asker:

Formally Invalid Arguments:

False and Invalid:
Some men are green!.
Socrates is a man!.
Therefore Socrates is green!.

True but Invalid:
Some men are mortal!.
Socrates is a man!.
Therefore Socrates is mortal!.

http://www!.triviumpursuit!.com/articles/f!.!.!.

HOWEVER another web site says something entirely different:
There are two formal fallacies sometimes mistaken for Modus Ponens and Modus Tollens!. These are known as (1) the fallacy of denying the antecedent; and (2) the fallacy of affirming or asserting the consequent!."
http://www!.sjsu!.edu/logic/study4!.htm#for!.!.!.

A deductive argument is said to be valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false!. Otherwise, a deductive argument is said to be invalid!.

A deductive argument is sound if and only if it is both valid, and all of its premises are actually true!. Otherwise, a deductive argument is unsound!.

http://www!.iep!.utm!.edu/v/val-snd!.htmWww@QuestionHome@Com

If I was guessing, I would go with "affirming the consequent" and "denying the antecedent," but I think that there are more "formal fallacies" (e!.g, ad populum, ad hominem, or post hoc ergo propter hoc)!.

Affirming the consequent is:
If A, then B
B
Therefore, A

Denying the antecendent is:
If A, then B
not A
Therefore, not BWww@QuestionHome@Com

They are quite simply Type I and Type II errors, false positive and false negative, respectively!. Comes from statistics, but applies to reasoning in general, the dichotomy of being wrong!.Www@QuestionHome@Com

There are definitely more than two, but you're probably referring to hypothetical syllogisms, in which case they are denying the antecedent and affirming the consequent!.Www@QuestionHome@Com

Pick any two ballrooms of your choice!.Www@QuestionHome@Com