Dear All,
Aslam O Alaikum

Is there anyone to elaborate the difference between formal and material fallacies? This is a question from Paper I (logic) 2013.
Please answer, i shall be grateful.

Regards

Abdul Moqeet

You will get a clear exposition of this concept from Copi's "Introduction to Logic".

Informal Fallacies:

These are such fallacies which are not the result of any inconsistency in the form of an argument, rather these are committed when we use ambiguous language or propositions are not directly supporting the conclusion.

For example consider the following argument which commits the fallacy of Ad Hominem:

His argument about Ms Hina's involvement in an embezzlement of gratuity funds must not be taken into consideration because he himself has been an accused of such a crime.

Now let me try to put into a syllogistic form:

All persons who have been convicted for a crime in his past, his argument for such a crime against someone else must not be taken into consideration.

Aslam has been convicted in the gratuity embezzlement funds.

Therefore, Aslam's argument against Ms Hina in embezzlement funds must not be taken into consideration.

Now friend here we see that there is no fallacy in the form of the argument as if we do standard translation of that argument according to which a person who is unique belongs to a class or category that has only one object, that person. So this is valid form of categorical Syllogism with mood and figure AAA-1 Barbara. Valid form and true conclusion but here fallacy is committed which is that the argument from such a person must not be accepted.

Formal Fallacy:

This fallacy is the result of inconsistency in the form of an argument.

Example:

All mammals are animals.
All Parrots are animals.

Therefore, all parrots are mammals.

Now this is a formal fallacy called "Fallacy of Undistributed Middle", We have to distribute the middle term in at least one premise. This is a syllogistic rule, in that argument middle term is not distributed so it is not among the 15 valid syllogistic forms. So that fallacy is in the form of the argument.

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Ever has it been that love knows not its own depth until the hour of separation.
But when love is one sided, holding off is no more an option.

Dear please refer to my question again, i have asked the difference between material and formal fallacies? the main confusion to me in this question is that what are "material fallacies"?

I look forward for your answer

Material Fallacies is the other name for Informal Fallacies, I have told you the difference that Formal fallacies are those which arise out of any anomaly in the form of the argument, while all other fallacies which are not Formal fallacies are called Material or Informal fallacies such as Fallacy of Relevance, fallacy of ad hominem etc.

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Ever has it been that love knows not its own depth until the hour of separation.
But when love is one sided, holding off is no more an option.

Definition of Logical Fallacy: Conclusion 'does' follow from the premises
Logical Fallacies are all those under Fallacies of Relevance (6 types).

Definition of Material Fallacy: No logical error because the conclusion 'does not' follow from the premises.
Material Fallacies are all except of Relevance e.g. Fallacies of Defective Induction (4 types), Fallacies of Presumption (3 types) etc

Brother you are misguiding or you yourself are mistaken, Material Fallacies do include Fallacies of Relevance, Defective Induction and Presumption, you are excluding all these three types from Material/Informal Fallacies which is wrong. These three fallacies are the part of Informal or Material Fallacies.

__________________
Ever has it been that love knows not its own depth until the hour of separation.
But when love is one sided, holding off is no more an option.

i am thankful to both of you. i personally agree with the former opinion. but if you both can please share the reference of your contentions, we can easily sort the problem.

Best regards

Brother what I said is self is self evident and Logically Valid, but if you really agree to the former opinion then I must say you do little hard work on your Logical concepts, and I must say that people have started opting Philosophy for its high scoring but have no aptitude for that. however, I am pasting the references as my corroborations, and I get out of that debate now.

http://www.britannica.com/EBchecked/...terial-fallacy
http://philosophy.avemaria.edu/post/...terial-fallacy
http://josecarilloforum.com/forum/index.php?topic=541.0
http://ocw.usu.edu/english/introduct...llacies-1.html
Ch # 4, Introduction to Logic by I.M Copi 14th ed

__________________
Ever has it been that love knows not its own depth until the hour of separation.
But when love is one sided, holding off is no more an option.

The Formal and Material Fallacies
Material fallacies
The material fallacies are also known as fallacies of presumption, because the premises "presume" too much--they either covertly assume the conclusion or avoid the issue in view. The classification that is still widely used is that of Aristotle's Organon – Sophistici elenchi / Sophistic Refutations:
(1) The fallacy of accident is committed by an argument that applies a general rule to a particular case in which some special circumstance ("accident") makes the rule inapplicable. The truth that "men are capable of seeing" is no basis for the conclusion that "blind men are capable of seeing."
This is a special case of the fallacy of secundum quid (more fully: a dicto simpliciter ad dictum secundum quid, which means "from a saying [taken too] simply to a saying according to what [it really is]"--i.e., according to its truth as holding only under special provisos). This fallacy is committed when a general proposition is used as the premise for an argument without attention to the (tacit) restrictions and qualifications that govern it and invalidate its application in the manner at issue. Example: Stealing is a crime. Stealing is a part of baseball. Therefore baseball is a criminal activity.
(2) The converse fallacy of accident argues improperly from a special case to a general rule. Thus, the fact that a certain drug is beneficial to some sick persons does not imply that it is beneficial to all people. a dicto secundum quid ad dictum simpliciter. Example: Every leaf I have seen is green, therefore all leaves are green. (3) The fallacy of irrelevant conclusion (Ignoratio Elenchi or ignorance of refutation) is committed when the conclusion changes the point that is at issue in the premises. Also called a ‘red herring.’ Special cases of irrelevant conclusion are presented by the so-called fallacies of relevance.
These include
(a) the argument ad hominem (speaking "against the man" rather than to the issue), in which the premises may only make a personal attack on a person who holds some thesis, instead of offering grounds showing why what he says is false,
(b) the argument ad populum (an appeal "to the people"), which, instead of offering logical reasons, appeals to such popular attitudes as the dislike of injustice,
(c) the argument ad misericordiam (an appeal "to pity"), as when a trial lawyer, rather than arguing for his client's innocence, tries to move the jury to sympathy for him,
(d ) the argument ad verecundiam (an appeal "to awe"), which seeks to secure acceptance of the conclusion on the grounds of its endorsement by persons whose views are held in general respect,

(e) the argument ad ignorantiam (an appeal "to ignorance"), which argues that something
(e.g., extrasensory perception) is so since no one has shown that it is not so, and
(f ) the argument ad baculum (an appeal "to force"), which rests on a threatened or
implied use of force to induce acceptance of its conclusion.
(4) The fallacy of circular argument, known as petitio principii ("begging the question"), occurs when the premises presume, openly or covertly, the very conclusion that is to be demonstrated (example: "Gregory always votes wisely." "But how do you know?" "Because he always votes the way I do."). A special form of this fallacy, called a vicious circle, or circulus in probando
("arguing in a circle"), occurs in a course of reasoning typified by the complex argument in which a premise p1 is used to prove p2; p2 is used to prove p3; and so on, until pn - 1 is used to prove pn; then pn is subsequently used in a proof of p1, and the whole series p1, p2, . . . , pn is
taken as established (example: "McKinley College's baseball team is the best in the association [pn = p3]; they are the best because of their strong batting potential [p2]; they have this potential because of the ability of Jones, Crawford, and Randolph at the bat [p1]." "But how do you know
that Jones, Crawford, and Randolph are such good batters?" "Well, after all, these men are the backbone of the best team in the association [p3 again]."). Strictly speaking, petitio principii is not a fallacy of reasoning but an ineptitude in argumentation: thus the argument from p as a
premise to p as conclusion is not deductively invalid but lacks any power of conviction, since no one who questioned the conclusion could concede the premise.
Example: We must fight them over there so that we won’t have to fight them over here.
(5) The fallacy of false cause (non causa pro causa) mislocates the cause of one phenomenon in another that is only seemingly related. The most common version of this fallacy, called post hoc ergo propter hoc ("after which hence by which"), mistakes temporal sequence for causal connection--as when a misfortune is attributed to a "malign event," like the dropping of a mirror.
A similar case is cum hoc ergo propter hoc, or mistaking correlation for causation. “Crime and poverty are typically correlated; therefore poverty causes crime.” Another version of this fallacy arises in using reductio ad absurdum reasoning: concluding that a statement is false if its addition to a set of premises leads to a contradiction. This mode of reasoning can be correct--e.g., concluding that two lines do not intersect if the assumption that they do intersect leads to a contradiction. What is required to avoid the fallacy is to verify independently that each of the original premises is true. Thus, one might fallaciously infer that Williams, a philosopher, does not watch television, because adding--
A: Williams, a philosopher, watches television.
to the premises
P1: No philosopher engages in intellectually trivial activities.
P2: Watching television is an intellectually trivial activity.

--leads to a contradiction. Yet it might be that either P1 or P2 or both are false. It might even be the case that Williams is not a philosopher. Indeed, one might even take A as evidence for the falsity of either P1 or P2 or as evidence that Williams is not really a philosopher. (6) The fallacy of many questions (plurimum interrogationum) consists in demanding or giving a
single answer to a question when this answer could either be divided (example: "Do you like the twins?" "Neither yes nor no; but Ann yes and Mary no.") or refused altogether, because a mistaken presupposition is involved (example: "Is it true that you no longer beat your wife? A yes or no answer will still be an admission of guilt to wife-beating.").
(7) The fallacy of non sequitur ("it does not follow") occurs when there is not even a deceptively plausible appearance of valid reasoning, because there is an obvious lack of connection between the given premises and the conclusion drawn from them. “Cleanliness is next to godliness.” Some authors, however, identify non sequitur with the fallacy of the consequent (see below Formal fallacies) and the Fallacy of False Cause (above).
Formal fallacies
Formal fallacies are deductively invalid arguments that typically commit an easily recognizable logical error. A classic case is Aristotle's fallacy of the consequent, relating to reasoning from
premises of the form "If p1, then p2." The fallacy has two forms:
(1) denial of the antecedent, in which one mistakenly argues from the premises "If p1, then p2" and "not-p1" (symbolized p1) to the conclusion "not-p2" (example: "If George is a man of good faith, he can be entrusted with this office; but George is not a man of good faith; therefore,
George cannot be entrusted with this office"), and (2) affirmation of the consequent, in which one mistakenly argues from the premises "If p1, then
p2" and "p2" to the conclusion "p1" (example: "If Amos was a prophet, then he had a social conscience; he had a social conscience; hence, Amos was a prophet"). Most of the traditionally considered formal fallacies, however, relate to the syllogism. One example may be cited, that of the fallacy of illicit major (or minor) premise, which violates the rules for "distribution." (A term is said to be distributed when reference is made to all members of the class. For example, in "Some crows are not friendly," reference is made to all friendly
things but not to all crows.) The fallacy arises when a major (or minor) term that is undistributed in the premise is distributed in the conclusion (example: "All tubers are high-starch foods [undistributed]; no squashes are tubers; therefore, no squashes are high-starch foods
[distributed]").

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