 10 Good Arguments
(Continued from EdWorld At Home)
1. Valid versus true: Includes discussion of Premise and Conclusion
An argument can't really be said to be true or false, because it's a point of view, a recommendation, an analysis, that is, it's the product of a person's (or many people's) ideas. So the rules we talk about when we cover the fallacies have to do with what is known as "validity." For an argument to be valid, its premises – the things that the argument is assuming to be true – must be put into a relationship by the person making the argument that entails the argument's conclusion.
Okay, let's take that apart some more.
A premise is that the sun comes up each morning, which is true.
Another premise is that newspaper arrived today before dawn, which is true.
Therefore the newspaper will always arrive before dawn would be a false conclusion because of fallacy #8 in the Logical Lies list. Just because one thing happens after another doesn't mean it was caused by that previous thing.
To "Entail" something is to make it necessary that it is so. Here are two premises and a conclusion that is entailed by the premises:
Premise: The rock garden gets no shade on sunny days.
Premise: Monday was a sunny day.
Entails Conclusion: The rock garden had no shade on Monday.
In fact, this is a valid argument that a detective might use. Let's say something connected to a crime had to happen in the shade in the rock garden on Monday. Well, since we know the rock garden would get no shade on Monday, maybe we're looking for people who were spotted carrying around umbrellas on a sunny day!
Detective stories are great for logic!
Go Back to the List of Good Arguments
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