An Introduction to Formal Logic
Supplement what you just read by reading the first chapter of this book. As you read, you will see the careful human thought that is required to create the logical constructs required to get the computer to do anything worthwhile. Section 1.6 begins the process of creating a formal syntax, or language, from human statements. In this course, we use the formal language Java to translate human statements into something that can be translated into the 1's and 0's the computer works with, the settings of the computer's electronic switches.
What is logic?
Logic is the business of evaluating arguments, sorting good ones from bad ones. In everyday language, we sometimes use the word 'argument' to refer to belligerent shouting matches. If you and a friend have an argument in this sense, things are not going well between the two of you.
In logic, we are not interested in the teeth-gnashing, hair-pulling kind of argument. A logical argument is structured to give someone a reason to believe some conclusion. Here is one such argument:
(1) It is raining heavily.
(2) If you do not take an umbrella, you will get soaked.
.˙. You should take an umbrella.
The three dots on the third line of the argument mean 'Therefore' and they indicate that the final sentence is the conclusion of the argument. The other sentences are premises of the argument. If you believe the premises, then the argument provides you
with a reason to believe the conclusion.
This chapter discusses some basic logical notions that apply to arguments in a natural language like English. It is important to begin with a clear understanding of what arguments are and of what it means for an argument to be valid. Later we will translate arguments from English into a formal language. We want formal validity, as defined in the formal language, to have at least some of the important features of natural-language validity.
Source: P.D. Magnus
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