I'm probably not the first to say this, but... I hear almost constant references to "what makes us human," "what separates us from the animals," and the like, including in contexts that have nothing to do with other animals or living things. I've even done it myself fairly recently, I believe. There's enormous variety in the specific characteristic mentioned, and they're all debatable. They also have a dark history of excluding certain humans from full moral consideration. Which leads me to wonder, what's the purpose of these alleged distinctions? Why is it so important to try to draw this specific line? What do they say about our attitudes towards the non-human?