Imagine the two following scenarios for this discussion:
Your Brother (or a similarly close relative) has been killed intentionally. His murderer stands trial for his crimes and is convicted. They have left his punishment up to you. Can you decide to have this murderer killed? Why or why not? (If you dont decide one way or another he will go free.)
Your Brother (or a similarly close relative) has killed a person intentionally and has received the death penalty for his crimes. They have left his punishment up to you. Can you conclude the same punishment for your brother as you did in the case above?
What would Kant say about your answers? Would he conclude that you acted on a universal maxim? If not, why not? What role does emotions have in your decisions and should they have any role? What would Kant say about the role of your emotions in your decisions?