Using "or" for reasoning with claims can often determine that an argument is valid or weak by looking at the role a compound claim plays in it(Epstein, p. 116).
For example:
Either mom brought the pizza home or dad.
Mom didn't bring the pizza home because she was home all day.
So it must be dad who brought the pizza home.
This argument is valid because there's no possible way for the premises to be true and the conclusion false at the same time.
Another example::
Jade owns a pet. Her pet is either a dog or cat. Her pet is a German Sheperd. So her pet must be a dog.
This argument is valid again because the premises are true and conclusion cant be false at the same time. This is also a strong argument because we all know that her premises are facts and a German Sheperd is a breed of a dog.
This is a very good argument. Using the word "or" makes the claims unsure of what they are talking about. I liked your example of the dog. Even though you used the word "or" in one of your premises, it still made sense because your conclusion could not have been false with your true premises. People should know that a German Sheperd is a dog, so there for your argument is strong because your conclusion could not be false when your premises are true. Overall, you used two very good examples in explaining using the word "or" and having your argument be a strong argument at the same time.
ReplyDeleteI think it's funny how in your statement you're still talking about valid and invalid arguments. I find it strange when you used a compound claim on your 2nd example about the german shepard. In my opinion, it seems kinda awkward when you say the "pet is either a dog or cat" because it doesn't really build up the argument as it gives more options in the argument.
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