Using Informal Logic in the Tutoring Session
We've been talking about various ways of helping writers to structure their arguments so that they are clear, persuasive, and logical. What we haven't yet discussed are ways that you might use instruction in logic in the tutoring session to help a writer analyze her ideas.
What follows are some steps you might take in analyzing the logic of a paper:
1) Ask the writer if she's familiar with syllogisms. If not, explain to her that a syllogism consists of two premises - a major premise and a minor premise - and a conclusion. Here is one example:
- All men are mortal.
- Socrates is a man.
- Socrates is mortal.
Here is another:
- All women are brilliant.
- I am a woman.
- I am brilliant.
You'll want to take the opportunity to explain to the writer that an argument can be logical without being true (as in the second example).
2) Establish the argument's logic by breaking her argument down into its component syllogisms. Deductive arguments rely on syllogisms in order to make sense. Go through the paper with the writer and try to find out what she is really arguing by unearthing the syllogisms buried in her prose.
3) Establish the argument's truth by testing the validity of its premises. Consider, for example, the following syllogism:
- Murder is wrong.
- Abortion is murder.
- Abortion is wrong.
This argument may be logical, but is it true? If you accept the second premise - that "abortion is murder" - then you have no choice but to accept the conclusion drawn here. But is this second premise necessarily true? A writer will need to consider, in this case, the terms he is using. For example, murder is defined as "the unlawful killing of another human being with malice aforethought" (Random House Dictionary of the English Language). We have two problems applying this definition to abortion: first, abortion is legal, and second, we can debate whether or not a fetus is indeed a human being. Both matters must be addressed by the writer if he wishes to make an argument along the lines of the one suggested in the syllogism above.
4) Look for suppressed assumptions. Let's say that the writer of the abortion argument understood that a controversy exists as to whether a fetus can be considered a human being - and he neglected to expose what he knew. In this case, the writer is suppressing assumptions. Writers suppress assumptions all the time and for all kinds of reasons - some legitimate, some suspect. One legitimate reason for suppressing an assumption is that your readers can be counted on to agree with what you have to say. For example, if the writer of the abortion argument is writing a pamphlet for a Right to Life group, he will not need to prove that abortion is murder because it is an assumption that members of this group already share. Still, you will want to be on the lookout for suppressed assumptions, and to question writers as to why their argument wasn't more explicitly made.
5) Consider each premise and the evidence that supports it. Is that evidence adequate? Current? Reputable? If not, the reader will remain unconvinced of the validity of the premises, and the argument will fail.