In CLOS, all classes are instances but not all instances are classes. It just so happens that the object that describes a class's slots, inheritance, etc is ..

In CLOS, all classes are instances but not all instances are classes. It just so happens that the object that describes a class's slots, inheritance, etc is ... an instance. Of what? A metaclass. Which is also an instance. It's confusing at first but eventually it all gels.