A category exists whenever two or more distinguishable objects or events are treated equivalently. This equivalent treatment may take any number of forms, such as labeling distinct objects or events with the same name or performing the same action on different objects. For example, a person might indicate the category “dog” by calling a German shepherd, a beagle, a cocker spaniel, and a chihuahua each “dog.” Or the person might indicate the category “things that can be thrown” by throwing a ball, a rock, and a stick.