I began another semester of Logic-teaching at Monroe County Community College. I'm using Vaughn's
The Power of Critical Thinking: Effective Reasoning About Ordinary and Extraordinary Claims.
Right at the beginning we have a claim that is logical but seems extraordinary to, I believe, many students. It is the logical claim of the non-relativity of truth. I explain it like this, and as I do I have the sense I am stepping on some of our relativistic culture's most cherished beliefs.
Logic is about evaluating and formulating arguments.
An argument is a series of sentences that are statements.
A statement (also called a "proposition") is a sentence that describes a certain (as Vaughn puts it) "state of affairs." A statement makes a claim that a certain state of affairs obtains. Another way to put it is like this: a statement is a sentence that is either true or false.
For example, consider the statement The lights in this room are on. This statement describes a certain state of affairs; viz., the lights in this room now being on. Now here comes the subjective-relativist crusher. If this statement is true (that is, if the state of affairs of the lights now being on obtains), then it is true for everybody. And if it is false, then it is false for everybody.
Consider the statement God exists. If that statement is true, it is true for everybody, even for persons who think it is false. And if that statement is false, then it is false for everybody, even for people who "know" there is a God.
But what about these statements? It's true for me that Pepsi is better than Coke. But it's true for you that Coke is better than Pepsi? Here the words It's true for me are redundant, unnecessary. At most they mean I believe, or I think. Such as: I think Pepsi is better than Coke. Now note this: If that statement is true, then it is true for everybody. And we have this state of affairs: John likes Pepsi better than Coke.
Vaughn's text is excellent at defeating subjective relativism and showing it to be illogical.
