Argumentation notes

Deductive Arguments:

To have such an argument, you must have 2 premises and a conclusion. If the premises are true, then the conclusion is normally true. There is, however, a difference between valid and true.

True conclusion and false premises = valid

True premises and false conclusion = valid argument but not a true one

Modus Ponens (mode of putting) - If P then Q. If P is true, then Q is true. If it can be proven that drivers on cell-phones get into more car crashes, then there should be a ban against drivers being able to talk on cell phones.

If premises and conclusions are true, then the argument is true. If one is false, it can still be valid. Then you have to defend and prove the premises.

Modus Tollens (mode of taking) - If P then Q. If not Q then not P.

Hypothetical Syllogism - if P then Q, if Q then R, then P is R. If Christian is Abby's brother, and Abby is Libby's sister, then Christian is Libby's brother.

Disjunctive Syllogism - P or Q ~ not P then Q. Libby or Sarah robbed the bank. If it wasn't Sarah then it was Libby! (bad Libby)