quality Living;      // has a life force
quality Anatomical;  // has a collection of body parts
quality Breathing;   // has limited range outside atmosphere
quality Mortal;      // can die
quality Injurable;   // can be wounded
quality Motivated;   // has goals
   // ... and so on

class Item;

class Thing is a Massive Palpable Item;

class Lifeform is a Living Anatomical Thing;

class Animal is a Breathing Mortal Injurable Motivated
                  Emotional Gendered Lifeform;

class Mammal is a Visible Viewing Eating Drinking
                  Listening Smelling Smelly Feeling Animal;

class Primate is a Wearing Manipulating Gestural
                   Facial Wielding Mammal;

class Human is a Sentient Carrying Talking Skilled Primate;