Functional and logical languages have their basis in mathematics, a science far more adept at modeling static systems than dynamic ones. Heeg contends that these kinds of languages lack the ability to model time, and must undergo awkward machinations to allow the systems built with them to change through time (this seems similar to the pain one experiences when modeling time in relational databases an area of research also steeped in mathematics). He likens traditional, functional languages to a pair of polarizing lenses, in which the model for real-world phenomena are first separated into their constituent states and processes, programmed, compiled, and (re)linked by a linker to create the program. By contrast, object-oriented languages make it much easier to build dynamic systems, because they map concepts much more directly into software. There is a one-to-one mapping between the model (Class) and the phenomena being modelled. Instead of "programming," you simply "model."
The grandaddy of the object-oriented world, Smalltalk has fascinated developers since it appeared on the programming scene. I was inducted in 1988, having succeeded in creating a small visual mapping application in about two weeks (my previous feats had included programs marginally more complex than those of the
"10 print 'hello'; 20 goto 10" variety). I was hooked. Though I'd just graduated from Biology, I signed up for a four-year compsci degree at Carleton University, a hotbed for Smalltalk education at the time.
That Smalltalk is an object-oriented language, however, doesn't really explain why it might be a better choice than other OO languages like C# or Java, and if so superior, why it has been supplanted by them as a language of choice for the enterprise in the last 10 years. This is the essence of the Smalltalk Paradox.
Heeg had some good answers for the first question. He began with solid material: a quote from the Goldberg/Robson Smalltalk bible:
"Smalltalk is based on a small number of concepts, but defined by unusual terminology. Due to the uniformity with which the object-message orientation is carried out in the system, there are very few new programming concepts to learn in order to understand Smalltalk...These concepts are presented by defining the five words...that make up the vocabulary of Smalltalk object, message, class, instance, and method. These five words are defined in terms of each other, so it is almost as though the reader must know everything before knowing anything."
Goldberg and Robson, Smalltalk-80: The Language and its Implementation, 1983.
In other words, the internal consistency of the language is at once beautiful and somewhat unsettling. As such, developers may find the concepts difficult to relate it to something else they already know.