Does it line up?

I want to thank Harrison for bringing this imagery to our minds. As we discussed whether or not an argument is valid, he processed it this way: "Does it line up?" That is a great way to define a valid argument. Does it line up? Does it add up? However, there's an important phrase to remember here and that is "If the premises are true. . . ." An argument may have premises that are ridiculous, but the test is this: If the premises were true, would the conclusion logically follow? That will always be the case in a valid argument. Take this example:
P1: Anyone who wishes to may go to Paris, France tomorrow.
P2: I wish to go to Paris, France tomorrow.
Therefore, I am going to Paris, France tomorrow.
Premise 2 is certainly true. If premise 1 were true also, then the conclusion would be logical and true, and I would be on my way to the airport! This means that the argument is valid, but it is not sound. So validity is a very important aspect of a persuasive argument, but validity alone will not get me to the Eiffel Tower. An effective persuasive argument will be sound as well as valid. Yes, we want our premises to line up and lead to the desired conclusion, but we also want our premises to be true. Anything else would certainly be "vain philosophy."
(Mrs. H.)