fallacy report

8/3/2019 Fallacy Report

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FALLACYof

FOUR

TERMS


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What isFALLACY?A "fallacy" is what we consider a

mistake, and a "logical fallacy on

that note is a mistake in reasoning.


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Importance ofIdentifying andUnderstandingFallacies


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Identifying and understanding sings ofFallacies of Reasoning allows one to.

spot and understand signs of fallaciesand thus make corrections to thesemistakes through the knowledge of whathas been done wrong convincingly andcorrectly.

gain understanding of which ones are

really the correct reasoning that leads youfrom the ideas of point A to point B .


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The Four TermFallacy(Latin quaternio terminorum)

..is aformal logical fallacy that occurs

when a syllogism has four (or more) terms rather

than the requisite three. This form of argument is

thus invalid.


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SyllogisticRule ViolatedAll valid categorical syllogisms have

exactly three terms, each of which is

used in the same sense throughout theargument.


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For example:

Valid Syllogism:

Major premise:All fish have fins.

Minor premise:All goldfish are fish.

Conclusion:All goldfish have fins.

Here, the three terms are: "goldfish", "fish", and"fins".


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Invalid Syllogism:

Major premise:All fish have fins.

Minor premise:All goldfish are fish.

Conclusion:All humans have fins.

The premises don't connect "humans" with "fins",

so the reasoning is invalid. Notice that there are

four terms: "fish", "fins", "goldfish" and "humans".

Two premises aren't enough to connect fourdifferent terms, since in order to establish

connection, there must be one term common to

both premises.


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More examples


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All dogs are animals, and all catsare mammals, so all dogs aremammals. The four terms are: dogs,

animals, cats and mammals.

Note: In many cases, the fallacy of four terms is

a special case ofequivocation. While the same

word is used, the word has different meanings,and hence the word is treated as two different

terms.

Example 1:


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Only man is born free, and nowomen are men, therefore, nowomen are born free.

The four terms are: man (in the sense of

'humanity'), man (in the sense of 'male'), and

women and born free.

Proof: Identify the four terms and where

necessary state the meaning of each term.

This is the easiest way to identify the

fallacy.

Example 2:


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Science is a very powerful and reliable tool; ithas allowed us to develop technology, and evento put men on the moon. So why would peopledeny the science of evolution?

Example 3:

The argument equivocates on the word science which caneither mean operational science or origins science. Operation

science is the reliable, trustworthy tool that is responsible for

technology. Origins science is an attempt to understand past

events in light of present evidence; its much more easily

tainted by historical bias than operation science and is notdirectly testable or repeatable. The two types of science

should not be mixed within an argument.


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Evolution is a fact, we see it in animals

as they adapt to their environment!

Example 4:

The first part of this statement is referring to allegedly idea

where animals change from one kind to another (common

descent) whilst the 2nd part is referring to the observable small

variation within the kind. This is also known as the bait-and-

switch fallacy. Evolutionists use a known scientific observation

and then later switch to another meaning to promote common

descent. This kind of argument is usually presented due toignorance of the theory or just a dirty trick. Unfortunately, in

my experience its usually the latter.


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Fallacy ofEquivocation

The Four Term Fallacy is otherwise known

as the Fallacy of Equivocation as a point of

view of informal logic. It is because the

Equivocation of the middle term is a

frequently cited source of a fourth term being

added to a syllogism. And this common error

is what we call the Ambiguous Middle.


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For example: (Fallacy of Equivocation)

"A poor lesson is better than a good lessonbecause a poor lesson is better than nothing, andnothing is better than a good lesson.

Note how in the following argument we have anuncomfortable feeling that the argument seems good withtrue premises, but the conclusion is obviously false.Often, we smile at arguments like these because we knowsomething is drastically wrong, but it is not initiallyintuitively obvious what it is. Knowing that a valid

argument cannot have true premises and a falseconclusion, and yet the argument appears to be perfectlyvalid, is a tip-off for the presence of the fallacy ofequivocation.


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Nothing is better than a good lesson.A poor lesson is better than nothing.A poor lesson is better than a goodlesson.

Obviously, there is something wrong with thissyllogism; this is evident from its humorousappearance. When we sketch a diagram,without attending to the meaning of the classes,

it is clear that the diagram would appear valid.How is this possible?


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Although the argument does not translate very well intostandard form categorical propositions, if we attempt todo so, we can see that the classes do not match. The word"nothing" is being used in two different senses. Oneattempt at translation yields:

No [lessons] are [things better than good lessons.]

All [poor lessons] are [things better than no lessons atall.]

All [poor lessons] are [things better than good lessons.]

Notice that we have more than three terms--our middleterm does not match. Hence, we cannot get a validdiagram.


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Another example of equivocation, a more tricky one:

Major premise: The pen touches the paper.

Minor premise: The hand touches the pen.

Conclusion: The hand touches the paper.

This is more clear if you use "is touching" instead of"touches". It then becomes clear that "touching the pen" isnot the same as "the pen", thus creating four terms: "thehand", "touching the pen", "the pen", "touching thepaper". A correct form of this statement would be:

Major premise:All that touches the pen, touches thepaper.

Minor premise: The hand touches the pen.

Conclusion: The hand touches the paper.


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ReducingTerms


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Sometimes a syllogism that is apparently

fallacious because it is stated with more than three

terms can be translated into an equivalent, valid

three term syllogism.


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For example:

Major premise: No humans are immortal.Minor premise:All Greeks are people.Conclusion:All Greeks are mortal.

This EAE-1 syllogism apparently has five terms:"humans", "people", "immortal", "mortal", and"Greeks". However it can be rewritten as a standardform AAA-1 syllogism by first substituting thesynonymous term "humans" for "people" and then by

reducing the complementary term "immortal" in thefirst premise using the inference knownas obversion (that is, "No humans are immortal." isequivalent to "All humans are mortal.").


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References:PHI1 Workbook 2011http://en.wikipedia.org/wiki/Fallacy_of_four_termshttp://www.toolkitforthinking.com/critical-thinking/anatomy-of-an-argument/deductive-logic-arguments/fallacy-of-four-termshttp://philosophy.lander.edu/logic/four_fall.htmlhttp://www.fallacyfiles.org/introtof.html

Presented by:

Longares, Michelle

Legaspi, Raquel

Armas, Joylie

Soriano, Daisyrie

Baylon, Rochelle

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