PHIL 3 Lecture 2: week 2 argument forms and propositional logic
Document Summary
Deductively valid argument: an argument such that it is not possible both for its premises to be true and its conclusion to be false. Deductively invalid argument: an argument such that it is possible both for its premises to be true and its conclusion to be false. Logical possibility: something that does not imply or involve a contradiction. Logical impossibility: something that does imply or involve a contradiction. Nothing to do with truth values of any of the statements in an argument. Nothing to do with whether or not any particular statement in an argument is. Assuming that (1) and (2) are both true, it is impossible for (3) to. Assuming that (1) and (2) are both true, it is possible for (3) to be false. Were (1) true, all that it would establish is that each person loves some other person. (2) claims that there is one single person that every person loves.
