It seems that the morphological properties of animals – properties like the color and size of their bodies – are intrinsic, while properties like being owned by the emperor are extrinsic. So perhaps we can articulate the metaphysical difference between our two systems of classification, one “natural” and the other not “natural,” by saying that the biological system has grouped together animals that are intrinsically similar to one another, while the Borgesian classification system has grouped together animals that are not intrinsically similar to one another, even if they are extrinsically similar.