The disagreement started once we saw all those new Olive Garden commercials doing it. Her point is that nothing is going to taste great with the same thing used twice in a dish. I say differently. Like if you add a good Italian sauce or something and use rigatoni noddles.
Pasta and potatoes are not the same thing, but you can cook and eat them together. Just cut the potatoes into chunks and add them to the water before you boil it, then add the pasta after it is boiling, then they should be finished cooking around the same time (potatoes need a little more time to cook than pasta).