I was walking along the bank of a stream when I saw a mother otter with her cubs. A very endearing sight, I'm sure you will agree, and even as I watched, the mother otter dived into the water and came up with a plump salmon, which she subdued and dragged onto a half-submerged log. As she ate it, while of course it was still alive, the body split and I remember to its day the sweet pinkness of its roes as they spilled out, much to the delight of the baby otters who scrambled over themselves to feed on the delicacy. One of nature's wonders, gentlemen: mother and children dining upon mother and children. And that's when I first learned about evil. It is built in to the very nature of the universe. Every world spins in pain. If there is any kind of supreme being, I told myself, it is up to all of us to become his moral superior.
-- Terry Pratchett, Unseen Academicals