One of the very first things that gets discussed in most philosophy courses is the definition of validity and soundness. An argument, roughly, is made any time some one tries to convince you to either do or belief in something by giving you reasons. These reasons are usually referred to as "premises," and they are offered in support of some conclusion. The conclusion is the thing that you are trying to get someone else to either do or believe.
A valid argument is an argument where if the premises were true, the conclusion would have to be true. Note: this does not mean that a valid argument is true. An argument can be valid without having true premises. Again, a valid argument is just an argument where if the premises were true, the conclusion would have to be true. A sound argument, on the other hand, is a valid argument with true premises. If an argument is valid and has true premises, then the argument is sound. If an argument is not valid, then it cannot be sound (and an argument cannot be sound if it's not also valid).
Here's an example that I use in class of an argument that doesn't count as valid. It comes from Young Money's song, "Bed Rock."
As Young Money artist Lloyd sings in the chorus:
I be stuck to you like glue, baby.
Wanna spend it all on you, baby.
My room is the G-spot.
Call me Mr. Flintstone,
Thus, we seem to have an argument for referring to Lloyd as 'Mr. Flintstone.' The argument can be reconstructed as follows:
Premise 1: My room is the G-spot
Premise 2: I can make your bed rock
Conclusion: Call me 'Mr. Flintstone'
(In the song P2 and C are flipped. I switched the positioning of each phrase to make it easier to follow.)
This is an argument because Lloyd is trying to convince you to call him 'Mr. Flintstone.' To support the conclusion that you should call Lloyd 'Mr. Flintstone' he offers two primary reasons (or, premises). First, his room is the G-Spot, and second, he can make your bed rock. Now, if this argument were valid, the conclusion would have to follow from the premises (regardless of whether the premises were true). So, if I were to give you the two premises, you should just know the conclusion. I ask, if Lloyd were to just give you these two bits of information:
1: His room is the G-Spot
2: He can make your bed rock
From these two statements alone, are you compelled to, or feel that you must, call Lloyd, 'Mr. Flintstone'? I hope not... As it stands this argument is not valid (i.e., the conclusion does not follow from the premises). Knowing that Lloyd's bedroom is the G-spot, and knowing that he can make your bed rock, does not entail that you (or anyone else) should refer to him as 'Mr. Flintstone.'
Here's another way of demonstrating validity and soundness. Is the following argument valid?
Premise 1: Hannah Montana is a woman
Premise 2: Joey Miller is Hannah Montana
Conclusion: Joey Miller is a woman
This argument is in fact valid. If the two premises were true, then the conclusion would have to be true. If I were Hannah Montana, and Hannah Montana were a woman, then I would also have to be a woman. While valid, this argument is not sound. Sadly, the second premise is not true: I am not Hannah Montana (no matter how badly I would like to be). Here's an example of a similar argument that is sound:
Premise 1: Hannah Montana is a woman
Premise 2: Miley Cyrus is Hannah Montana
Conclusion: Miley Cyrus is a woman
This argument, just like the previous one, is valid. Unlike the previous argument, however, this argument contains all true premises. As such, this argument is sound.
While the argument given by Lloyd and Young Money isn't valid, it seems like there may be some suppressed premises that we could articulate to make the argument valid. I need some help filling in these suppressed premises though. Any thoughts?
Oh, and just because she's helped me to make this point in numerous classes, shout out to Hannah Montana!