You: An afterbirth is also the product of reproduction; would you feel comfortable including it under your definition?

Aaron: That is a ridiculous and disgusting example. An afterbirth obviously is not alive as it does not meet any of my other criteria. You might as well argue that every hair that falls from your head is a living thing just because it was produced by a human body.

You: I suppose that I did speak before really thinking my idea through. In any case, your definition should not allow exceptions, and the mule is an exception.

Aaron: I never meant my definition to be exhaustive. The fact is, you and I both know a living thing when we see one.