The Importance of Teaching Logic

"'Logic!' said the Professor half to himself. 'Why don't they teach logic at these schools?'"

The Lion, the Witch and the Wardrobe, Chapter 5

At St. Timothy's, we begin the study of logic as a separate class in the curriculum in the seventh grade. This is the age, as every parent knows, when children start asking their parents for good reasons: "Why do I have to go to bed at nine?" "Why should I study all these boring subjects?" and even "Why should I obey you, anyway?" They also start to be more attentive to, and more influenced by, the world around them with its constant, pressing voice: "You will be so much happier if you buy this!" or "Vote for me!" The logic curriculum harnesses pre-teens' naturally questioning - some might say argumentative - nature, directs them away from themselves, and asks them to look rather toward the strength or weakness of the argument itself. It encourages them to sort through their motives and to look at the cogency of the reasons they give or are given for following one course of action or another.

Informal Logic

The St. Timothy's logic curriculum is divided into two years. The students begin in the seventh grade with informal logic. Loosely speaking, the study of informal logic is the study of clear reasoning - the sort of reasoning which helps us to point our thoughts in the right direction and come to a reasonable conclusion, generally by sorting through evidence, identifying unspoken assumptions, and rejecting irrelevancies. Informal logic is the sort of logic which helps us to work out where the water is coming in through the basement wall, why we should support one charity over another, and why we can have a cookie four hours before dinner, but not one hour before.

All of us who have read The Lion, the Witch, and the Wardrobe, will recall the scene near the beginning of the book where Peter and Susan go to the Professor because they are worried that Lucy is either lying or mad. He helps them to set aside irrelevant issues (the question of whether Narnia is real or not, Edmund's rejection of Lucy's story), reject their unproven assumptions (that things that are real are "there" all the time), and to focus on the real issue: Lucy's truthfulness. The conclusion he comes to is, "For the moment then and unless any further evidence turns up, we must assume that she is telling the truth." The Professor does not assert that Lucy is truthful, but rather advises that her siblings should believe her because the best evidence they have suggests that she is trustworthy. Conclusions based on informal logic are weak or strong, and become stronger or weaker as they are put to further tests.

Formal Logic

We use the conclusions arrived at from informal reasoning to serve as the basis for formal logic, which the eighth grade studies. Formal logic is called "formal" because it focuses on the form of an argument rather than on the content .The curriculum revolves around the "syllogism," which is the familiar form of proof involving two premises and a conclusion. In formal logic, an argument is valid if its conclusion follows from its premises. In a valid argument, if the premises are true, then the conclusion must also be true. For instance, if we say that all oaks are trees, and that all trees are living things, then it follows that all oaks are living things. The two premises are true, and so the conclusion which follows from them is also true.

The trajectory of the eighth grade formal logic class is to bring students to be able to express ordinary arguments in syllogistic form, test them for validity, and then for truth. Reading between the lines, we see that the Professor does a little of this in his conversation with Peter and Susan. If, he warns, it is true that Lucy always speaks the truth - all times that Lucy speaks are times that Lucy tells the truth -, and that she has been speaking about going to Narnia - the story about Narnia is a time when Lucy speaks -, it stands to reason that the story about Narnia is true - the story about Narnia is a time Lucy is telling the truth.

In a nutshell, the logic curriculum establishes something of a toolkit that students can use to spot bad arguments, to make good ones, and to come to true conclusions based on true evidence. Parents, however, should be prepared. As children become more alert to bad arguments, parents need to make sure that their positions are well reasoned, clear, and both valid and true. Be forewarned: "Because I say so!" will not work as well as it used to!