A Slice of Life: Concept Hierarchies and Pizza Delivery
An adapted excerpt from Philosophy for Heroes: Knowledge.
In our lifetime, we learn many concepts. A “concept” is determined by the nature of an entity. A simple example: we learn the concept of “furniture” early on, and as we are introduced to types of furniture (e.g., high-chair, table, bed), we can apply what we know about the original concept to new entities. Hence, we need not consider each situation (i.e., something to sit on, or sleep on) over and over again. If we apply these dependencies of specialization to more general concepts, a structure arises—a concept hierarchy.
A concept hierarchy is a tree-like structure consisting of concepts, defined by the definitions of given connections (e.g., “chair” and “table” are furniture, the concept “furniture” would thus constitute the root of a tree and “chair” and “table” are two successive branches).
Let us consider the example of a pizza delivery company. There, orders, inquiries, customers, and employees must be managed. The first step of management is an accurate grasp of the current situation. Instead of verbally surveying each employee and customer and placing a summary in a file, we abstract the properties of the relationship to each respective person. The employees may have much to tell about their lives, but only a few items of data are important for the payment of their wages, such as a name and bank account number. The same holds for the client, for whom we actually require only a delivery address. In addition, we must manage our products (the pizzas) and the individual inquiries and orders. In the construction of our concept hierarchy, we try to determine only the relevant properties of an entity and disregard all other information.
As all the parts of our pizza company should at the same time refer to identifiable entities with a creation date, they should inherit from a more general concept named “entity.” And obviously, “clients” and “employees” are persons; we can thus let properties such as the address inherit from a more general concept, “person.” With the definition of “order” and “request,” we must in both cases reference the person placing the order (customer) and the employee processing the order (employee), and thus generalize the properties in a concept called “process.” Let us supplement these definitions with properties of the customer (his account), the employee (his position in the company), the order (the ordered product), and the request (the customer’s message); we now obtain a schematic construction of this small slice of the world:
As this example shows, a concept hierarchy allows us to base our understanding of reality on things we know to be true. We can add details as necessary, but we don’t need to reinvent the wheel (or the pizza) from scratch every time.
And that, my friend, explains what pizza and philosophy have in common: begin with what is true, rely on that, and allow that to direct your decisions.