Hierarchies of Categories

But there is also much more that I know about the behavior of Flo, not just because she is a Florist, but because she is a Shop keeper. I know, for example, that there will be money exchanged for the transaction, I will get a receipt, and so on. This behavior is common to both florists and grociers, or any other type of shop keeper. I know Flo is a Human being, and thus exhibits all the human behaviors of language and the like. I know she is a Mammal, and a Material Object.

At each level of abstraction I know certain bits of information. That information is applicable to all lower, that is nore specialized, levels of abstraction.

[audio] 24 [real] 24 Text to accompany slide 24, in Chapter 1 of An Introduction to Object-Oriented Programming