For example: suppose I had a very simple list, with two columns: "Name" and
"Number". The category "name" has three items: Dog, Cat, and Dog. Each of
those three items has a corresponding "number" value: 3, 4, and 5. I'm
trying to find a function that would recognize the fact that I have "Dog"
listed twice, and would sum the 3 & 5 values listed next to each "Dog",
leaving me with a two-item list: Dog, 8 & Cat, 4.

Is there a way to do this?