Tuesday 9/18
Truth Phobic Language I
Readings
Notes
- PC Translations(from last time)
- The Rules of Analytic Tableaux (from last time)
- Extracting Arguments
- Informal Fallacies
Synopsis
Today we worked through some natural language arguments, translating them into the Propositional Calculus so as to determine their validity (by Truth Table, or by Analytic Tableaux). We showed what happens in a Truth Table when an argument is invalid (that is, discovering a row with all true premises and a false conclusion) and what happens in Analytic Tableaux when an argument is invalid (that is, not all branches die, showing that it is possible to assert the premises while denying the conclusion.)
Further, I demonstrated how to 'read off' from the living branch of the Analytic Tableaux of an invalid argument the precise row on which the premises are all true and the conclusion false--thereby showing how the information contained in the Truth Table of an argument is reflected in the information contained in its Analytic Tableaux counterpart.
Finally, we set the stage for our discussion of truth-phobic language by discussing the paradigmatic argumentative context found in a courtroom. Next time we take up specific ways in which prosecution and defense can mislead, deliberately, in presenting their arguments.