A superclass is a group of numbers determined by the way that humans can perceive them. Although he does not take credit for their invention, Robert Munafo coined the term in analogy with his own classes. The superclasses are defined as: Robert Munafo also defines: * Superclass 0: The number can be experienced by certain animals, for example, three. * Superclass 6: The number is so big that nobody can understand its definition well enough to know anything useful about it, for example, BB(100) in the busy beaver function.