Fasllacy And Its Kind

Fallacy It came from t he Latin word “fallo” which means “I deceive” and “fallere” which means “to deceive” TWO GENERAL CLASSIFICATIONS Fallacies of a Language Equivocation

Division It is a fallacy of considering words or statements separately when they should have been considered as a whole.EXAMPLE:X University is vital to Catholic Education Mr. Y is a professor of X University Ergo, Mr. Y is vital to Christian Education Accent

Division

This kind of fallacy arises due to difference in interpretation brought about by misplaced emphasis on a phrase, word or syllable in a proposition.

Accent

EXAMPLE:

Amphiboly Composition

Figures of Speech Equivocation

You may laugh as you like. (Meaning: Others may laugh)

You may laugh as you like. It is a fallacy consisting of using a word that has the same spelling or sound but the meaning is different, (Meaning: You are not prohibited from laughing) in different parts of the inference. You my laugh as you like. EXAMPLES (Meaning: It is permissible that you laugh or not to laugh) Every water is in liquid form. We should water Figures of Speech the plant everyday. Ergo, we should This kind of fallacy is a special type of false analogy that plant everyday in liquid form. consist in wrongly inferring similarity of meaning Every pen is a writing instrument. The cage of a from similarity of word structure pig is a pen. Ergo, the cage of a pig is a EXAMPLE writing instrument. Amphiboly What is immaterial is not material It is a fallacy expressed in using a statement whose meaning is ambiguous exposing it to various interpretations.

and what is insoluble is is not soluble; ergo, what is inflammable is not flammable. Accident

EXAMPLES 1. My wife Jenny said to her sister Eva that she has to go to the mall. Due to this formulation of the argument, we are at the lost of who is actually being referred to as “she”. Is it Jenny or Eva? 2. “While standing one leg, the boy played with his dog” Who is standing on one leg: the boy or the dog? Composition

This fallacy is involved in affirming or denying of a thing what has been affirmed or denied only of some accidental modification or condition of the thing or vice versa EXAMPLE “You say that you ate what you bought; but you bought a raw meat; ergo, you must have eaten raw meat. Confusion of Absolute Statement This fallacy uses a principle that uses absolutely true statements but restricted by practical limitations

EXAMPLE It is a fallacy of considering words or statements as a whole when they should be considered separately. “Water boils at 212 Fahrenheit In other words, it is an error of stating that what is true of the parts is also true of the whole. ergo, water boils at 212 Fahrenheit on the top of Mt. Everest EXAMPLE: Begging the Question Those who topped the 1999 Bar Exam are from This fallacy is a.k.a.as petitio principii is involved when Cebu we assume a conclusion is proving what is not known in the premises Jose of UST is the 1999 Bar Topnotcher Ergo, Jose of UST is from Cebu

EXAMPLES

All in this room are wearing shoes

EXAMPLES

but Martha is in this room

Cows give milk

ergo, Martha is wearing shoes False Cause

but sheep have wool ergo, goats chew their cud

Also known as “non causa pro causa” This fallacy is involved from a conclusion of causal with a non-causal relationship under the form of “post hoc, ergo propter hoc” (after this, therefore because of this)

As a student of a Catholic school, I will become a minister later. Ignoratio elenchi It came from the Latin ignoratio = irrelevant

EXAMPLE Night comes before the day ergo, night causes the day

Don’t look directly at the sun otherwise, the sun will punish you

elencho = conclusion This fallacy is involved when we prove other conclusions not the issue t be concluded It has various minor forms as presented below: Argumentum ad hominem This fallacy is the Latin for “attack or appeal to the man”

A man cannot think without his brain Ergo, a man’s brain is the cause of his thought Consequent

This fallacy is involved in court hearings when the defense or prosecution is attacking the dignity of the person or witness instead of weighing the evidences presented

This fallacy is involved when we infer that an antecedent EXAMPLE is true because the consequent is true “Your honor, it would be very difficult for us not to EXAMPLE believe that the accused of this murder case is not guilty, because his father and grandfather has been A dog is an animal convicted of murder several years ago. And besides, the accused is of bad moral reputation.” but Moby Dick is an animal Argumentum ad populum ergo, Moby Dick is a dog This is known as “appeal to people” where popular prejudice is preferred rather than truth and reason where an argument may be believed by most, if not A dog is an animal by all people, although that argument may not be but Moby Dick is not a dog true ergo, Moby Dickis not an animal Many Question This is also known as Complex Question This fallacy is involved when we are asking either a multiple question as though it were a single question demanding a yes or no answer EXAMPLE

EXAMPLE “Clinically proven safe and effective…” “The only earth structure visible in space is the Great Wall of China.” Save the user, jail the pusher “If you will vote for me…” Argumentum ad misericordiam

Have you not given up the habit of cheating in my class?

This is “appeal to pity” a kind of fallacious argument that arises when an appeal to evidence is replaced by an appeal to pity, mercy or sympathy EXAMPLE

Have you stopped beating your wife?

“Please, just give me a 3.0 grade. Ishould not receive a failing grade since it is my 3rd time to take this Logic subject”

Non Sequitur It is the Latin of “it does not follow” This fallacy is involved to true but unrelated propositions without any connections

“The accused in robbery case must not be put to jail, because he is a father of 12 children and his wife is in the hospital suffering from stage 3 cancer.”

Agumentum ad vericundiam This is “appeal to awe, modesty, shame, respect or authority” committed by overawing people by the dignity of those who hold the opinion without special reference to the truth they hold

Consider, for example, the categorical syllogism: No geese are felines. Some birds are geese. Therefore, Some birds are not felines.

Clearly, "Some birds are not felines" is the conclusion of this syllogism. The major term of the syllogism is "felines" The Roman Catholic Church… “The earth is the center of (the predicate term of its conclusion), so "No geese are the Universe.” felines" (the premise in which "felines" appears) is its major Argumentum ad baculum premise. Simlarly, the minor term of the syllogism is "birds," and This is “appeal to force or appeal to might” arises when "Some birds are geese" is its minor premise. "geese" is the one appeal to intimidation, or use of force in order middle term of the syllogism. to gain acceptance of his propositions EXAMPLE

EXAMPLE

Standard Form

President of a state to the citizens: “Commit In order to make obvious the similarities of structure shared by heinous crimes and you will surely enjoy the lethal different syllogisms, we will always present each of them in the injection.” same fashion. A categorical syllogism in standard form always begins with the premises, major first and then minor, and then finishes with the conclusion. Thus, the example above is already in Father to his son: “If you will not be serious with standard form. Although arguments in ordinary language may be your studies, your future will be bleak. And you can offered in a different arrangement, it is never difficult to restate them never expect me to lift finger to help when you in standard form. Once we've identified the conclusion which is to need me.” be placed in the final position, whichever premise contains its Argumentum ad ignorantiam predicate term must be the major premise that should be stated first. The “appeal to ignorance” is committed when we infer a false statement because it cannot be proved, true because it cannot be refuted. EXAMPLE This evidence must be accepted because it cannot be refuted

You cannot declare me guilty since you cannot prove it. Categorical Syllogisms The Structure of Syllogism

Medieval logicians devised a simple way of labelling the various forms in which a categorical syllogism may occur by stating its mood and figure. The mood of a syllogism is simply a statement of which categorical propositions (A, E, I, or O) it comprises, listed in the order in which they appear in standard form. Thus, a syllogism with a mood of OAO has an O proposition as its major premise, an A proposition as its minor premise, and another O proposition as its conclusion; and EIO syllogism has an E major premise, and I minor premise, and an O conclusion; etc. Since there are four distinct versions of each syllogistic mood, however, we need to supplement this labelling system with a statement of the figure of each, which is solely determined by the position in which its middle term appears in the two premises: in a first-figure syllogism, the middle term is the subject term of the major premise and the predicate term of the minor premise; in second figure, the middle term is the predicate term of both premises; in third, the subject term of both premises; and in fourth figure, the middle term appears as the predicate term of the major premise and the subject term of the minor premise. (The four figures may be easier to remember as a simple chart showing the position of the terms in each of the premises:

Now, on to the next level, at which we combine more than one categorical proposition to fashion logical arguments. A categorical syllogism is an argument consisting of exactly three categorical propositions (two premises and a conclusion) in which there appear M P P M M P a total of exactly three categorical terms, each of which is used P M exactly twice. 1 \ 2 | 3 | 4 / One of those terms must be used as the subject term of the S M S M M S conclusion of the syllogism, and we call it the minor term of the M S syllogism as a whole. The major term of the syllogism is whatever is employed as the predicate term of its conclusion. The third term in All told, there are exactly 256 distinct forms of categorical the syllogism doesn't occur in the conclusion at all, but must be employed in somewhere in each of its premises; hence, we call it the syllogism: four kinds of major premise multiplied by four kinds of minor premise multiplied by four kinds of conclusion multiplied by middle term. four relative positions of the middle term. Used together, mood and Since one of the premises of the syllogism must be a categorical figure provide a unique way of describing the logical structure of proposition that affirms some relation between its middle and major each of them. Thus, for example, the argument "Some terms, we call that the major premise of the syllogism. The other merchants are pirates, and All merchants are premise, which links the middle and minor terms, we call the minor swimmers, so Some swimmers are pirates" is an IAIpremise.

3 syllogism, and any AEE-4 syllogism must exhibit the form "All Diagramming Syllogisms P are M, and No M are S, so No S are P." The modern interpretation offers a more efficient method of evaluating the validity of categorical syllogisms. By combining the drawings of individual propositions, we can use Venn diagrams to Form and Validity assess the validity of categorical syllogisms by following a simple This method of differentiating syllogisms is significant because the three-step procedure: validity of a categorical syllogism depends solely upon its logical 1. First draw three overlapping circles and label them to form. Remember our earlier definition: an argument is valid when, if represent the major, minor, and middle terms of the its premises were true, then its conclusion would also have to be syllogism. true. The application of this definition in no way depends upon the content of a specific categorical syllogism; it makes no difference 2. Next, on this framework, draw the diagrams of both of the whether the categorical terms it employs are "mammals," syllogism's premises. "terriers," and "dogs" or "sheep," "commuters," and • Always begin with a universal proposition, no "sandwiches." If a syllogism is valid, it is impossible for its matter whether it is the major or the minor premises to be true while its conclusion is false, and that can be the premise. case only if there is something faulty in its general form. 3. Remember that in each case you will be using only two of the circles in each case; ignore the third circle by making Thus, the specific syllogisms that share any one of the 256 distinct sure that your drawing (shading or × ) straddles it. syllogistic forms must either all be valid or all be invalid, no matter what their content happens to be. Every syllogism of the form AAA1 is valid, for example, while all syllogisms of the form OEE-3 are invalid. This suggests a fairly straightforward method of demonstrating the invalidity of any syllogism by "logical analogy." If we can think of another syllogism which has the same mood and figure but whose terms obviously make both premises true and the conclusion false, then it is evident that all syllogisms of this form, including the one with which we began, must be invalid. Thus, for example, it may be difficult at first glance to assess the validity of the argument: All philosophers are professors.

4. Finally, without drawing anything else, look for the drawing of the conclusion. If the syllogism is valid, then that drawing will already be done. Since it perfectly models the relationships between classes that are at work in categorical logic, this procedure always provides a demonstration of the validity or invalidity of any categorical syllogism. Consider, for example, how it could be applied, step by step, to an evaluation of a syllogism of the EIO-3 mood and figure, No M are P. Some M are S. Therefore, Some S are not P.

All philosophers are logicians. Therefore, All logicians are professors. First, we draw and label the three overlapping circles needed to represent all three terms included in the But since this is a categorical syllogism whose mood and figure are categorical syllogism: AAA-3, and since all syllogisms of the same form are equally valid Second, we diagram each of the premises: Since the major premise is a universal proposition, we may begin with it. The or invalid, its reliability must be the same as that of the AAA-3 diagram for "No M are P" must shade in the entire area in which syllogism: the M and P circles overlap. (Notice that we ignore the S circle by All terriers are dogs. shading on both sides of it.) All terriers are mammals. Now we add the minor premise to our drawing. The Therefore, All mammals are dogs. diagram for "Some M are S" puts an × inside the area where the M and S circles overlap. But part of that area (the portion also inside the P circle) has already been shaded, so our × must be placed in the remaining portion. Both premises of this syllogism are true, while its conclusion is false, so it is clearly invalid. But then all syllogisms of the AAA-3 Third, we stop drawing and merely look at our result. Ignoring the M form, including the one about logicians and professors, must also be circle entirely, we need only ask whether the drawing of the invalid. conclusion "Some S are not P" has already been drawn. This method of demonstrating the invalidity of categorical Remember, that drawing would be like the one at left, in syllogisms is useful in many contexts; even those who have not had which there is an × in the area inside the S circle but the benefit of specialized training in formal logic will often outside the P circle. Does that already appear in the acknowledge the force of a logical analogy. The only problem is that diagram on the right above? Yes, if the premises have the success of the method depends upon our ability to invent been drawn, then the conclusion is already drawn. appropriate cases, syllogisms of the same form that obviously have true premises and a false conclusion. If I have tried for an hour to But this models a significant logical feature of the syllogism itself: if discover such a case, then either there can be no such case because its premises are true, then its conclusion must also be true. Any the syllogism is valid or I simply haven't looked hard enough yet. categorical syllogism of this form is valid. Here are the diagrams of several other syllogistic forms. In each case, both of the premises have already been drawn in the

appropriate way, so if the drawing of the conclusion is already drawn, the syllogism must be valid, and if it is not, the syllogism must be invalid. AAA-1 (valid) All M are P. All S are M. Therefore, All S are P. AAA-3 (invalid) All M are P. All M are S. Therefore, All S are P.

All M are S. Therefore, Some S are not P. Four of the fifteen valid argument forms use universal premises (only one of which is affirmative) to derive a universal negative conclusion: One of them is "Camenes" (AEE-4): All P are M. No M are S. Therefore, No S are P. Converting its minor premise leads to "Camestres" (AEE-2):

OAO-3 (valid) Some M are not P. All M are S. Therefore, Some S are not P.

All P are M. No S are M. Therefore, No S are P. Another pair begins with "Celarent" (EAE-1):

EOO-2 (invalid) No P are M. Some S are not M. Therefore, Some S are not P. IOO-1 (invalid) Some M are P. Some S are not M. Therefore, Some S are not P.

Names for the Valid Syllogisms

No M are P. All S are M. Therefore, No S are P. Converting the major premise in this case yields "Cesare" (EAE-2): No P are M. All S are M. Therefore, No S are P. Syllogisms of another important set of forms use affirmative premises (only one of which is universal) to derive a particular affirmative conclusion:

A careful application of these rules to the 256 possible forms of categorical syllogism (assuming the denial of existential import) leaves only 15 that are valid. Medieval students of logic, relying on The first in this group is AII-1 ("Darii"): syllogistic reasoning in their public disputations, found it convenient All M are P. to assign a unique name to each valid syllogism. These names are Some S are M. full of clever reminders of the appropriate standard form: their initial Therefore, Some S are P. letters divide the valid cases into four major groups, the vowels in order state the mood of the syllogism, and its figure is indicated by (complicated) use of m, r, and s. Although the modern interpretation Converting the minor premise produces another valid form, AII-3 of categorical logic provides an easier method for determining the ("Datisi"): validity of categorical syllogisms, it may be worthwhile to note the All M are P. fifteen valid cases by name: Some M are S. The most common and useful syllogistic form is "Barbara", whose mood and figure is AAA-1: All M are P. All S are M. Therefore, All S are P. Instances of this form are especially powerful, since they are the only valid syllogisms whose conclusions are universal affirmative propositions. A syllogism of the form AOO-2 was called "Baroco": All P are M. Some S are not M. Therefore, Some S are not P. The valid form OAO-3 ("Bocardo") is: Some M are not P.

Therefore, Some S are P. The second pair begins with "Disamis" (IAI-3): Some M are P. All M are S. Therefore, Some S are P. Converting the major premise in this case yields "Dimaris" (IAI-4): Some P are M. All M are S. Therefore, Some S are P. Only one of the 64 distinct moods for syllogistic form is valid in all four figures, since both of its premises permit legitimate conversions: Begin with EIO-1 ("Ferio"):

No M are P. Some S are M. Therefore, Some S are not P. Converting the major premise produces EIO-2 ("Festino"): No P are M. Some S are M. Therefore, Some S are not P. Next, converting the minor premise of this result yields EIO-4 ("Fresison"): No P are M. Some M are S. Therefore, Some S are not P. Finally, converting the major again leads to EIO-3 ("Ferison"): No M are P. Some M are S. Therefore, Some S are not P. Notice that converting the minor of this syllogistic form will return us back to "Ferio."