Good chefs know the importance of maintaining sharp knives in the kitchen. What’s their secret? A well-worn Taoist allegory offers some advice. The king asks about his butcher’s impressive knifework. “Ordinary butchers,” he replied “hack their way through the animal. Thus their knife always needs sharpening. My father taught me the Taoist way. I merely lay the knife by the natural openings and let it find its own way through. Thus it never needs sharpening” (Kahn 1995, vii; see also Watson 2003, 46). Plato famously employed this image as an analogy for the reality of his Forms (Phaedrus, 265e). Just like an animal, the world comes pre-divided for us. Ideally, our best theories will be those which “carve nature at its joints”. While Plato employed the “carving” metaphor to convey his views about the reality of his celebrated Forms, its most common contemporary use involves the success of science -- particularly, its success in identifying distinct kinds of things. Scientists often report discovering new kinds of things -- a new species of mammal or novel kind of fundamental particle, for example -- or uncovering more information about already familiar kinds. Moreover, we often notice considerable overlap in different approaches to classification. As Ernst Mayr put it: No naturalist would question the reality of the species he may find in his garden, whether it is a catbird, chickadee, robin, or starling. And the same is true for trees or flowering plants. Species at a given locality are almost invariably separated from each other by a distinct gap. Nothing convinced me so fully of the reality of species as the observation . . . that the Stone Age natives in the mountains of New Guinea recognize as species exactly the same entities of nature as a western scientist. (Mayr 1987, 146) Such agreement is certainly suggestive. It suggests that taxonomies are discoveries rather than mere inventions. Couple this with their utility in scientific inference and explanation and we have compelling reason for accepting the objective, independent reality of many different natural kinds of things...