[Physicist]

bipedalism developed because two shoes are cheaper than four.

Ah, but our knuckle-walking ancestors had opposable big toes, so they would have worn four gloves, and gloves are cheaper than shoes. (Just ask O.J.)

[PatrickHenry]

Shoes or gloves, two or four, all I know is that when my ancestors came down from the trees and stepped out onto the ground they did it in grand style, with the music from "2001" swelling in the background.