PHI 1101 Lecture Notes - Lecture 13: Modus Tollens, Modus Ponens

• School: University of Ottawa
• Department: Philosophy
• Course: PHI 1101
• Professor: Laura Byrne

Document Summary

This lecture is short due to the professor returning the first midterm in class. If you have x you are going to have that y. e. g. being a cat is sufficient for being classified as a mammal. How to show a sufficient condition statement is false: look for an instance of x that is not an instance of y. Conditions that are both necessary and sufficient: e. g. if you are a properly registered student then: having a grade of 50% or higher is. Individually necessary and jointly sufficient: you have necessary conditions, they are not sufficient because they cannot guarantee the sufficient, when taken together they give a sufficient condition or guaranteed consequent. E. g. cataclysmic storm that hardly ever occurs due to certain conditions being in place such as an air and sea temperature, humidity, pressure etc. Only when all of these individual things come together will lead to the sufficient storm in this case.