I made this handout for my Ethics students. We're studying the Golden Rule, which is one of 13 normative ethical theories covered in the course. Here is the formal statement of the theory:
For all acts x, x is right if and only if the agent, in performing x, treats others as he or she wants to be treated.
I have a question for you: Can the Golden Rule be extended to nonhuman animals? If so, how; if not, why not?