批判性思维的培养(2)Critical_Thinking--Analyzing_and_Evaluating_Arguments

The Principle of Charity
• Why use the Principle of Charity?
– When we are generous and respectful, we encourage others to act in the same way. – When we use the Principle of Charity, we make our opponent’s argument as strong as it can be. We improve more from confronting challenging opponents than from attacking weak ones.
Part Two: Logical Fallacies
• Fallacies of Relevance
• Common Fallacies of Relevance • Fallacies of Insufficient Evidence • Common Fallacies of Insufficient Evidence
• However, this is WRONG!!
Deductive Arguments
• Deductive arguments claim that if their premise is true then their conclusions must be true.
– A common pattern for deductive arguments is:
• Thus, fallacies of relevance occur when people try to support an argument with irrelevant information.
Common Fallacies of Relevance
• Personal Attack: instead of analyzing and evaluating the argument on its own merit, we attack the quality of the person making the argument.
The Principle of Charity
• Inexperienced writers often treat their opponents with a high level of skepticism. • This is a terrible habit to get into. Instead we should try to remember to always follow the Principle of Charity when dealing with someone’s opposing argument.
Critical Thinking: Analyzing and Evaluating Arguments
Kathleen Maloney Lanzhou University May 11, 2009
Reminder:
• Authors: Greg Bassham, William Irvin, Henry Nardone, and James M. Wallace • Title: Critical Thinking: A Student’s Introduction • Location: Foreign language library, third floor of the main library.
Probably Likely It is plausible to suppose… One would expect that…
These indicator words are quoted from Bassham, Irwin, Jones, and Wallace, Critical Thinking, page 57.
– A common inductive argument pattern is:
Things like X tend to be Y. I expect a new X. It will probably be Y.
Deductive vs. Inductive
Deductive Arguments Claim That…
All A is B. All B is C Therefore, all A is C.
Inductive Arguments
• Inductive arguments simply try to show that if their premises are true, then their conclusions are probably true.
• Some common deduction indicator words are:
Certainly Definitely Absolutely Conclusively It logically follows… It is logical to conclude… This entails that… It must be the case that…
Outline of Lecture Series
• May 4th, 2009: Critical Thinking—An introduction • May 11th, 2009: Critical Thinking— Analyzing and Evaluating Arguments
• May 18th, 2009: Critical Thinking—Skills for Reading and Writing
These indicator words are quoted from Bassham, Irwin, Jones, and Wallace, Critical Thinking, page 57.
Induction Indicator Words
• Some common induction indicator words are:
It is impossible for all of the premises to be true and the conclusion false.
It is unlikely that the premises are true and the conclusion is false.
The truth of the premises guarantees the truth of the conclusion.
Fallacies of Relevance
• Remember from last week the importance of relevance (相关 ) in critical thinking.
• Fallacies (谬论) are false or mistaken ideas that often sound plausible but are in fact untrue or illogical.
If the premises are true, then the conclusion must be true.
Inductive Arguments Claim That…
If the premises are true, then the conclusion probably is true.
The Principle of Charity
• ―When interpreting an unclear argument or passage, always give the speaker or writer the benefit of the doubt.‖ • ―Never attribute to an arguer a weaker argument when the argument permits us to attribute to him or her a stronger one.‖ • ―And never interpret a passage as a bad argument when the evidence reasonably permits us to interpret it as not an argument at all.‖
The truth of the premises makes the conclusion likely
This table is quoted from Bassham, Irwin, Jones, and Wallace, Critical Thinking, pages 55-56.
Deduction Indicator Words
The Principle of Chຫໍສະໝຸດ Baidurity
• ―When interpreting an unclear argument or passage, always give the speaker or writer the benefit of the doubt. Never attribute to an arguer a weaker argument when the argument permits us to attribute to him or her a stronger one. And never interpret a passage as a bad argument when the evidence reasonably permits us to interpret it as not an argument at all‖ (59).
• Part Five: Summary and Activity
Part One: Deduction and Induction
• Deductive vs. Inductive Arguments
• Deductive and Inductive Indicator Words • The Principle of Charity
• Attacking the Motive: instead of analyzing and evaluating the argument on its own merit, we claim that the person making the argument is doing so for selfish reasons.
Common Fallacies of Relevance
• Two Wrongs Make a Right: when we try to justify a wrongful act by showing that another act is just as bad or worse.
Outline of Today’s Lecture
• Part One: Deductive Arguments vs. Inductive Arguments
• Part Two: Logical Fallacies • Part Three: Analyzing Arguments
• Part Four: Evaluating Arguments
Deductive vs. Inductive Arguments
• People often describe the difference between deductive arguments and inductive arguments in the following way:
– Deductive arguments move from general premises to particular conclusions. – Inductive arguments move from particular premises to general conclusions.