8-Identifying Implicit Premises rev2a PDF

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Identifying Implicit Premises Adapted from

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http://www.wwnorton.com/college/phil/logic3/ch5/assume.htm

An argument is a relationship between a set of premises and a conclusion. But people rarely express in words all the premises they are using. Most arguments contain some premises that are implicit rather than explicit. INSTRUCTIONS Do the following exercises (including 2 examples) and bring your answer to class. You may be called upon to give yours aloud. Example 1: Suppose we are planning a hiking trip, and I tell you that Sally can't come because she has a broken leg. My argument clearly assumes that people with broken legs can't go hiking, but I didn't bother stating that premise, because it was too obvious. When we analyze an argument, it is important to identify the assumed premises. They can then be labeled--using letters instead of numbers to distinguish them from explicit premises-- and included in the diagram. There are two basic rules

we should follow in interpreting or analyzing an argument by providing assumed

premises:

1The premise we supply should close the logical gap between the stated . premise and the conclusion, and 2The premise we supply should not commit us to more than is necessary. . So no now w, use those two ba basic sic rrules ules to deter determine mine w wha ha hatt the implicit premise is is.--> ____________________________________________________ Example 2: Suppose you are taking French as a visiting student at the University of Paris, and you learn that some of your classmates are failing; you infer they do not enjoy the subject. The task, now, is to identify the assumed premise in your argument. Consider the following candidates. And use those two rules (above) to decide what the implicit premise is. Circle the right answer

French is a Romance language. B. Paris is beautiful in the springtime. C. People can always learn to enjoy difficult challenges. D. Students do not enjoy subjects in which they are failing. A.

Deter Determi mi mine ne the Implicit Pr Premise emise follo llo llowing wing ar argument. gument. 1. Identify the assumed premise in the fo President Clinton will not be successful in Bosnia because he is a rookie at w war ar ar.. Circle the right answer a)

Pres President ident Clinton wi will ll not be successful in Bosnia.

b)

No one who took a def defer er erment ment from militar military y ser service vice can be successfully conduct a w war ar ar..

c)

No one will be successful in Bosnia.

d)

No one who is a rookie at war will be s successful uccessful in Bosnia.

2. Identify the assumed premise in the fo follo llo llowing wing ar argument. gument. A heroic mo movie vie w would ould indu induce ce more violence than a slasher one in which the vill villain ain is punished fo forr his violence because the hero in heroic mo movies vies is rewar rewarded ded fo forr his violence. Circle the right answer

a)

The hero of a her heroic oic mo movie vie is rrewarded ewarded for his violence.

b)

A heroic mo movie vie might induce more violence than slasher ones in which the villai villain n is punished fo forr his violence.

c)

Any mo movie vie that rewards violence encoura encourages ges more violence than one tthat hat punishes it.

d)

Punishing the villains of a violent mo movie vie is a way to prev prevent ent violence among mo movie vie viegoer goer goers. s.

3. Identify the assumed premise in the fo follo llo llowing wing ar argument. gument. Fetal studies ha hav ve shown tha thatt individuals ar are e initially biased to tow war ard d right-handedness. Ho Howe we wev ver er,, a rrecent ecent study showed that that there were more left-handed individuals show among ffetuses etuses subject to stress, suc such h as prolonged labor or under undernourishment, nourishment, then w would ould be e expected. xpected. Circle the right answer

a)

Stress causes individ individuals uals to s switc witc witch h from being right-handed to being left-han left-handed. ded.

b)

Resear esearch ch cher er ers s hadn't done enough research on the factors influencing handedness until the most recent studies were done.

c)

Stress causes brain dama damage ge in ffetuses. etuses.

d)

Genes, rather than en environmen vironmen vironmental tal ffactor actor actors, s, deter determine mine handedness....