1. Coined by college students P&S in honor of the popular belief that everybody has a twin somewhere.
2. The promise takes precedence of any other form of promise such as mother or God or the pinky. It protects the sanctity of mothers and of God so as not to desecrate these magnanimous personalities.
3. Replaces all other forms of swears with the unknown twin - one that you would wish to meet some day, and upon whom you would never wish ill.
I promise I speak the truth - twin swear!