of knowledge. He is coming to know objects by understanding their relationships with other objects. Fido would be one such object. With additional experience and education, we learn to organize these groups into larger groups. Eventually, we learn that Fido, Rover, Spot, and others themselves form a group that we call “dog.” That represents an advance in learning, for it means that we recognize significant similarities among these animals and differences between them and other types of animals. Indeed,