It is not the purpose of a psychological typology to classify human beings into categories - this in itself would be pretty pointless. Its purpose is rather to provide a critical psychology which will make a methodical investigation and presentation of the empirical material possible. C.G. Jung
That’s a simplistic illustration but it holds the conceptual kernel which informs the idea of a typology. It’s an intellectual tool which emerged in the 19th century to assist in the organization of fast-accumulating mountains of data into carefully or loosely defined categories in many research fields and which came into full flowering in the 20th century. It’s closely related to but is not exactly a synonym for a classification system although both ideas, categorization and classification, are central to the idea of a typology. In general, handling information by means of a typological approach can be found in applications ranging from the crudely simplisticas the aphorism above suggeststo the highly sophisticated. And since categories and classes depend on definition, the model possibilities which result from a typological approach are endless.
Of course, like all conceptual instruments, a typology will have its problems. Consider the relatively simple problem of classifying or categorizing the gender of homo sapiens if the definition of the two types is based on human genitalia, an obvious way of defining each type,
There would seem to be only two types: male and female, so a two category typological model quickly emerges. But, hold on. There’s something missing in the model. It’s incomplete because it doesn’t provide for the type of human which possesses genitalia characteristics of both male and female: the hermaphrodite. That means the model has to be revised if it is to encompass the entire population of our species. In other words, everything depends on how a “type” is defined.
For an illustration of the role definition plays in establishing the nature of a typology in general, as distinct from but in addition to its component types, take a look at this archaeological site.
Define a type too broadly and it doesn’t tell you much. Define the types in a typological model too narrowly and the number escalates out of sight.
Now consider the incredibly complex problem of classifying or categorizing human behavior. It’s certainly an old problem. Every civilization has made the effort and provided us with a range of human behavioral models, many of which are still functioning as integral parts of such different cultures as the Chinese, the Hindu and Buddhist societies, though the results are to be found in philosophy rather than psychology without the benefit of the term “typology”. For the West, our “typological” progenitors are the Greeks, and their thinking about the subject has influenced 2,500 years of our history. But I digress.