"What is it like to be a bat?” the philosopher Thomas Nagel asked in 1974. “How do forests think?” asked anthropologist Eduardo Kohn more recently. As we barely understand the totality of our own selves (much less that of another person), how can we even begin to know what it would be like to be a chair, a coastline, a beetle, a virus? Given the state of the world today, thinking about how we think the nonhuman (and other humans) is urgent. Yet any time we think about something, that something is inevitably filtered through our humanness. How can acknowledging the hybrids that are created when we think things help us to better share the planet and, difficult that it may be, better empathize with one another? This essay looks at how humanist writers in the Italian Renaissance worked to decenter the human and, as such, did not conceive of “man as the measure of all things” in the way that many posthuman studies have claimed. Leon Battista Alberti, Leonardo da Vinci, and Andrea Alciato, for example, attempted to “think like” the nonhuman, and in doing so, they consciously created textual nonhumans in their writing through both anthropomorphosis and the more empathic strategy of allomorphosis, in which a writer attempts to “think like” something other-than-human. The textual nonhumans of Renaissance humanism are fascinating creations of minds that sought to bind themselves to the beauties, powers, and mysteries of the nonhuman world in order to become better humans in the here and now.