Study Guide: Lesson 4
A Little Logic

Lesson Overview

Logic is the primary tool or methodology in studying philosophy. Philosophy is about analyzing and constructing arguments and a good understanding of the basics of logical reasoning is essential in performing that task. The next 3 lessons will focus on logic and analyzing arguments. In this lesson, you will first be introduced to the laws of logic. These are the first principles for all reasoning. We will then discuss the specialized terminology we use in logic. Finally, we will examine 2 major kinds of logical reasoning: deductive and inductive. We will consider different forms of arguments under each and discuss how to evaluate these arguments. Take note that a large part of this lesson is about learning the terminology for logic.

Tasks

Read and take notes from chapter 5 of Philosophy: Critically Thinking about Foundational Beliefs, “A Little Logic.” As you read, make sure you understand the following points and questions:

* Why are the laws of logic foundational? * The Law of Logic makes discourse possible. If they are not recognized as true, than nothing we claim makes any sense. Therefore, it is important to have a firm grasp of these laws. * List and explain the 3 laws of logic. 1. Noncontradiction – “Something cannot both be and not be at the same time and in the same respect. Expressed symbolically: ~ (P•~P).² It reads, “It is not the case that there can be both P and non-P”. 2. Edcluded Middle – “Something either is or is not, or Pv~P. A thing either exists or it does not; there is no tertian quid (“third what”). 3. Identity – “Something is what it is. Formula, “P = P”. Whatever a particular thing is, it is that particular thing. * Know the symbolic expression of the law of non-contradiction and how it clears up confusions. * ~ (P•~P): The ~ means “not” or