About six months ago I stopped eating meat. I was teaching a graduate course at UCLA that investigated how Italian Renaissance writers conveyed their concepts about the human through writing about the nonhuman – plants, animals, objects, angels, demons, gods and God. As weeks passed, I found myself becoming more and more attuned to the nonhuman entities all around me, more aware of their vibrant lives. Cutting flowers for a short-lived bouquet seemed wrong; chewing on animal flesh became flat out impossible.

Leonardo da Vinci was one of the authors we were studying in the course. Out of the thousands of pages comprising his 25 documented codices, known collectively as his “Notebooks,” we read passages describing the natural world and its inhabitants, and some of his philosophical maxims, fables and riddles.