What is Critical Thinking??

Critical thinking is an approach to decision-making that involves careful reading and listening, sharp thinking, logical analysis, good visualization, and healthy skepticism.

Hints and Strategies for Critical Thinking

1. Read or listen carefully! Determine exactly what is given, as opposed to what is assumed and what is to be determined.

2. Identify the real issue. Be alert for statements that divert attention from the real issue.

3. If dealing with an argument, identify premises and conclusion. Rewrite the argument, if necessary, to determine its flow from premises to conclusion

4. Look for informal and formal fallacies.

5. Identify ambiguous terms, assumptions, and missing information that must be used to reach the conclusion.

6. Use pictures, tables, and Venn diagrams to organize information. Visual aids are helpful, if not essential.

7. Evaluate the underlying evidence. Question authority and ask whether the premises are based on facts or opinions.

8. Are other conclusions possible? A set of premises can lead to more than one plausible conclusion.

Critical Thinking Examples

Colorado Amendment 2

In 1992, Colorado voters made a decision on a ballot initiative concerning gay rights. Here is the actual text that appeared on the ballot:

Shall there be an amendment to the Colorado constitution to prohibit the state of Colorado and any of its political subdivisions from adopting or enforcing any law or policy which provides that homosexual, lesbian, or bisexual orientation, conduct, or relationships constitutes or entitles a person to claim any minority or protected status, quota preferences, or discrimination?

Explain the meaning of a yes vote and a no vote on this initiative.

Buying the Best Airline Ticket

Airlines typically offer many different prices for the same trip. Analyze the following situation. You are planning a trip six months in advance and discover that you have two choices in purchasing an airline ticket:

(A) the lowest fare is $1100, but 25% of the fare is nonrefundable if you change or cancel the ticket; or

(B) a fully refundable ticket costs $1900.

Which ticket should you buy?

What’s the Real Issue?

Analyze the following segment of an editorial in a local newspaper.

With last Saturday’s sellout crowd at the Moonlight Amphitheater, it is clear that the parking problem has become hopeless. Concertgoers parked along residential streets up to a mile away from the amphitheater, badly overcrowding sidewalks, blocking driveways, and disrupting traffic. Until the situation improves, future rock concerts will have to be suspended.

CD Club Offer

12 CDs for 1¢.

I’ve enclosed $1.50 (that’s 1¢ for 12 CDs, plus $1.49 for enrollment charge). I agree to buy 6 CDs at regular Club prices within the next two years.

A shipping/handling charge is added to each shipment. Applicable sales tax added to each order.

Why didn’t you get 12 CDs for 1¢?

Building More Prisons

Analyze the following argument:

We should build more prisons because incarcerating more criminals will reduce the crime rate.

Income Tax Regulations

According to Internal Revenue Service (IRS) guidelines on who must file a federal income tax return, a single person who can be claimed as a dependent on another person’s tax return and is either 65 or older or blind must file a return if

(i) earned income was more that $5,350 ($6,400 if 65 or older and blind); or

(ii) unearned income was more that $1,750 ($2,800 if 65 or older and blind); or,

(iii) gross income was more than the total of earned income (up to $4,300) or $700, whichever is greater, plus $1,050 ($2,100 if 65 or over and blind).

(a) Chase is a single 35-year-old bachelor who is claimed as a dependent on his parent’s tax return. He has an earned income of $6500. Does this policy apply to Chase? If so, must he file an income tax return?

(b) Carmen is a single 24-year-old blind woman who is claimed as a dependent on her parent’s tax return. Her earned income is $6500 and her unearned income is $750. Does this policy apply to Carmen? If so, must she file an income tax return?

(c) Serena is a single 68-year-old blind woman who is claimed as a dependent on her son’s tax return. Her gross income is $2,500 and her earned income is $550. Does this policy apply to Serena? If so, must she file an income tax return?

99¢ Phone Calls

A long distance carrier advertises 99¢ phone calls to anywhere in the United States for “up to 20 minutes.”

Do you accept the offer??

Reading a Lease

Landlord shall return the security deposit to resident within one month after termination of this lease or surrender and acceptance of the premises, whichever occurs last.

What does it mean??

Sorting Out Presidents.

U.S. Presidents William Henry Harrison, Franklin Pierce, and Theodore Roosevelt represented three different political parties (Republican, Democrat, and Whig, but not necessarily in that order) and came from three different states (New Hampshire, Ohio, and New York, but not necessarily in that order).

a. If Roosevelt was the Republican and the president from New York was Republican, does it follow that Roosevelt was from New York?

b. If Pierce was from New Hampshire and the Whig was not from New Hampshire, does it follow that Pierce was not a Whig?

c. If the Whig was not from New York and the Harrison was not from New York, does it follow that Harrison was not a Whig?

Read Carefully!!

Linda is 31 years old, single, outspoken, and very bright. As a student, she majored in philosophy and was deeply concerned with issues of discrimination and social justice. She also participated in antinuclear demonstrations.

Which is most likely?

· Linda is a bank teller.

· Linda is a bank teller and is active in the feminist movement.

Low birth weight, smoking mothers, and Venn diagrams.

Results of a survey of 350 mothers.

(U.S. National Center for Health Statistics)

Table shows number of mothers in each category.

	Low Birth weight	Normal Birth weight
Smoking	18	132
Nonsmoking	14	186

Human Blood Groups

Human blood can be classified according to whether three antigens, A, B, and Rh, are present or absent. The absence of A and B is denoted type O. The presence and absence of Rh are denoted Rh⁺ (Rh positive) and Rh^- (Rh negative), respectively. The table shows the eight major categories of blood and their approximate frequency (in percentage terms) in the U.S. population. Draw a Venn diagram to illustrate these data.

Blood type	Frequency is population
A positive	34%
B positive	8%
AB positive	3%
O positive	35%
A negative	8%
B negative	2%
AB negative	1%
O negative	9%