PHI 1101 Lecture Notes - Lecture 18: Co-Premise, Middle Term, Obversion

• School: University of Ottawa
• Department: Philosophy
• Course: PHI 1101
• Professor: Sascha Maicher

Document Summary

Valid deductive arguments prove or demonstrate their conclusion if the premises of such an argument are true, the conclusion cannot fail to be true as well. Categorical logic: when we argue categorically, we are arguing in a deductive way, and the conclusions necessarily follow (reaching absolute, certain answers) 1) if you are under the age of 18 you are legally a minor. 2) if you are legally a minor then you cannot be sued. C(cid:895) therefore, if (cid:455)ou are u(cid:374)der the age of 18, (cid:455)ou (cid:272)a(cid:374)"t (cid:271)e sued. Categorical claim: claim about a class of things, and some thing that predicates this class of things. When you are talking about a category of thing (class) in the world to represent some type of unity: ex: chairs are a class of things. Note: there are two categories of categorical claims: a/i affirm something, e/o negate something. Universal claims: about the entirety of the category; all or nothing claims.