Thanks for the question! So valid and invalid arguments have to do with whether or not the conclusion follows logically from the premises; if they do, it’s a valid argument, and if they don’t, it’s an invalid argument. Here’s the classic example of a valid argument:
All men are mortal. Socrates is a man. Therefore, Socrates is mortal.
We can see that here, the conclusion follows logically from the premises. The following example of an argument is an invalid one:
If it’s lunch, I will eat a burrito. I am eating a burrito. Therefore, it is lunch.
We can see that this is a classic example of a mistaken reversal. I could, for example, be eating a burrito outside of lunch hours, and so it’s not logically necessary that it’s lunch time based on the fact that I’m eating a burrito based on our premises. Anytime a logical error is made that results in the conclusion being inappropriately reached, the argument is an invalid one.
The LSAT normally won’t ask you directly whether or not a question is valid or invalid. Being able to identify an invalid argument is helpful for identifying flawed arguments on the LSAT. We can basically consider invalid arguments and flawed arguments the same on the LSAT, so there’s no need to distinguish between invalid arguments and flawed arguments. Normally, we would also consider something called “soundness”—whether the premises are actually true—but on the LSAT, we always assume that if a premise is given to us, it is true, and so this isn’t something we need to worry about.
Hope this helps! Feel free to ask any other questions that you might have.
