Understanding the Object Model

Objective-C has a Smalltalk-like object model. If you come from Java, you will find this very easy to understand. If you come from a Simula-family language, such as C++, you may find it a bit more diffcult.

Alan Kay described the idea of objects as a simple exercise in reduction. When solving a problem, you want to decompose it into simple parts. The simplest thing that can run a part of a program is the same thing that can run the whole of a program: a computer. Objects, in Alan Kay’s vision, are simple models of computers that communicate by exchanging messages.