1. Critical Thinking- Analysis of an Argument
G.P. Taylor, Ph.D.
University of Texas at San Antonio

2. Critical Thinking Deciding rationally what to or what not to believe
Norris, Stephen P. "Synthesis of Research on Critical Thinking. Educational Leadership, v 42 n 8 May

3. Critical Thinking
Careful and deliberate determination of whether to accept, reject, or suspend judgment.
Moore and Parker, 1994.

4. In Science, Critical Thinking is used when you…
Observe problem/phenomenon/conceive ideas
Develop a hypothesis
Make predictions: Formulate experiments
Test Predictions: Carry out experiments/analyze data
Draw conclusions from results, modify hypothesis
Modify as needed and do again.
Reject or confirm hypothesis
The Scientific Method itself involves critical thinking
VITAL for a scientist.
Impressive for a science student
Need to have time to read and think

5. Scientists are Natural Skeptics
Big thing to learn during Grad school:
Be critical of everything!
What can you doubt about a scientific paper?

6. Possible Doubts for Paper
Are their ideas supported by prior findings?
Are their techniques correct?
Why did they choose the techniques they chose?
Can their machines measure what they say?
Did they do the correct controls (could the effect arise from some other factor??)
Does their data look “random” enough?
Did they analyze their data correctly?
Did they use correct statistical techniques?
Did they interpret their data correctly?
Are their conclusions supported by the data?

7. Here, we’ll practice being critical
Analyze during class.
1 exercise from the GRE questions pool
Identify major problems with given arguments

8. How to Approach? Given: There are flaws? What are they?
Where are the problems?
Analyze line of reasoning
Consider questionable assumptions
Does evidence support the conclusion?
What additional evidence is needed to strengthen or weaken argument?
What other info is needed to evaluate the conclusion?

9. Weak Analogy
Conclusion about one thing, based on success or failure of another…with many other variables present
Ex: A biotechnology company is doing well in SA…I’ll open one as well…

10. Confusing Cause and Effect
Ice cream consumption leads to criminal behavior…
Other factors: Summer heat, out of school, etc…

11. Necessary and Sufficient
Necessary- No other ways of getting effect
Sufficient- Can cause effect

12. Unrepresentative Statistics
Sample large enough
Sample representative of overall population in relevant characteristics
How many are needed?
What works there…does it here?

13. Assuming no change over time
Old stats may not been representative of today…

14. Narrow Either-Or Reasoning
Must choose only one path…
Perhaps both courses of action are okay?
Are other courses of action feasible?

15. Directions: Identify conclusion Identify supporting evidence
Brainstorm and identify three or four discrete flaws (see prior slides), plus any others that you note.
How to strengthen argument? (What additional info is needed)

16. Example:
Last year the local television news program In Focus reported in its annual car-and-truck safety survey that over the course of the last 10 years, United Motors vehicles were in involved in at least 30% fewer fatal accidents to drivers than vehicles built by any other single manufacturer. Now, United is developing a one-of-a-kind kind computerized crash warning system for all its trucks. Clearly, anyone concerned with safety who is in the market for a new truck this year should buy a United Motors truck.

17. Example
Conclusion: Truck buyers should favor the UM truck over others…
Evidence Presented:
Compiled TV station-calculated 10 year fatality rate on all UM vehicles
Development of new truck safety system

18. Logic Problems: Survey: General Problems
30%...total accidents or per vehicle sold??? (not percentage data, but seems to be actual numbers)
what % fatal accidents included? Where is data from?
30% of all vehicles, not trucks alone
Non-fatal also relevant to safety
Geographic effects (fewer AM vehicles; In Focus local?)
Was safety consistent? No changes in trucks over 10 years?
Maybe UM worse…why new system needed?
The new safety feature is effective
New system not yet included- irrelevant to current purchases

19. How would you strengthen Argument??

20. To Strengthen the Argument:
Accident sample information
Trucks instead of vehicles analyzed
Other measures of safety (non-fatal)
Safety was consistent over time
New safety features included and effective