Philosophy 12A

Logic is about reasoning, the difference between good and bad reasoning, and how to tell the difference between good and bad reasoning.

In this course, we will develop techniques for laying bare the structure of arguments (“reasonings”). This will enable us then to characterize, in some precise ways, the difference between good and bad reasoning, and to formulate rules of correct reasoning. These three things — a conception of structure of arguments, a precise characterization of good and bad arguments in terms of their structure, and a system of rules of correct reasoning — constitute a “system of logic.” We will actually consider several systems of logic. After all this, students should be in a better position to properly formulate and evaluate logical arguments.

The course will focus on deductively correct reasoning. That is, we will consider “good reasoning” to be reasoning in which the truth of the premises absolutely guarantees the truth of the conclusion (as in typical correct mathematical reasoning). This will briefly be put into perspective in relation to inductively good reasoning, in which the premises give significant, but not conclusive, support for a conclusion.

Textbook: Modern Logic by Graeme Forbes, Oxford University Press, 1994.