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

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 1985. 40-45.

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

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

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

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?

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

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?

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…

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

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

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

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

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

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)

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.

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

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

How would you strengthen Argument??

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