How to Reason and Argue (Reconstruct an Argument)

Standards for evaluating an argument

• Vices
• Virtues

Vices in an argument

• One or more premises is/are FALSE
• Premises do not provide a good Reason for the Conclusion
• Relation between premises and conclusion

Virtues in an argument

• Validity
• Use the clause IF .... ONLY IF ...

          IF the clause is valid and ONLY IF the conclusion is valid

          EVERY argument with true premises and  a false conclusion is invalid.

• Soundness

         A sound argument, all the premises are true and the conclusion is true.

         If a deductive argument is not sound, then it is not a good argument

Deductive Arguments

• The conclusion should follow from the premises
• Validity
• A deductive argument is supposed is valid
• An inductive argument is supposed not to be valid 

Argument Reconstruction 

1. Stage 1: Close Analysis
• Do a close analysis
2. Stage 2: Get down to the basics
• Remove all excess verbiage
• List all explicit premises and conclusions in standard form.
3. Stage 3: Sharpen edges
• Clarify where needed
• Break up where possible without distortion
4. Stage 4: Organize parts
• Divide the arguments into sub-arguments and arrange them in order
5. Stage 5: Fill in gaps
• Assess whether each argument is valid
• Add suppressed premises where needed
• Check each premise for truth
• Qualify premises to make them true where needed if possible
6. Stage 6: Assess the argument
• Conclude

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Organize Parts

1. Identify and number and premises and conclusion.
2. When premises work together, put a plus sign between them and draw a line under them
3. Draw arrows from reasons to claims that they are reasons for.
4. Rearrange as necessary