The Problem of Thinking and Consciousness

Elizabeth Costello claims that because she was able to "think" herself into one of her fictional characters that, before, had never existed, then she should be able to think herself into any being. This claim does not sit well with me, as I find that there are many intrinsic problems that make it untrue. First, Costello's ability to think herself into another human character doesn't necessarily mean much; it would have been much easier to put herself into another character's shoes given that the character was another human being. Part of the reason she was able to think herself into the character was because she was able to empathize with human emotion. Another flaw with her statement is that she really isn't thinking herself into an entirely new being; after all, she may have invented the fictional character, but it was, essentially, of her own entity. My question is therefore, why is it more difficult for humans to empathize with animals (which is what we are in all actuality)? When answered "consciousness", Elizabeth Costello replies, "They have no consciousness, therefore. Therefore what? Therefore we are free to kill them? Why? What is so special about the form of consciousness we recognize that makes killing a bearer of it a crime while killing an animal goes unpunished?" I find this to be the more important question, and statement. What is consciousness, and how are we able to differentiate between the consciousness of another human being and the consciousness of an animal? Sometimes, I wonder if my interior narrative is different or nuanced in different levels than those around me. If that was true, does that mean that I have a different "consciousness"? I found that The Lives of Animals prompted many questions from me that I never knew I had.