Think about the relationship between researching a biography of a complex individual and compiling a set of theories about personality development. The individual, Mr. X, is a particular person whose life and personality took shape through a long series of contingent happenings. The biographer's task is to arrive at some insights into Mr. X's motivations and desires; his features of character (courage, magnanimity); his weaknesses; as well as providing an illuminating account of some of the shaping events and choices that Mr. X made along the way. Mr. X's actions and choices are comprehensible -- but in order to understand them we need to know what he thought, wanted, intended, resisted, and chose, and why. In other words, we need a fairly detailed profile of Mr. X's personality, preferences, and vanities. We need to know Mr. X as a particular and unique person.
Now it is worth commenting that this biographical description is itself a generalization. When we write that "Mr. X was concerned about how his actions were perceived, and often acted out of a desire to put his actions in a good light" -- we are making a generalization across Mr. X's lifetime of choices. And we are also hypothesizing something not directly observable -- a persistent feature of Mr. X's subjective world of choosing, his self-consciousness. In the course of the biography we might make statements such as "Mr. X chose to stay in his job at the New York Times because it was very prestigious; whereas Ms. Y was more adventurous in her career and moved to Slate.com." This comparison implies that both X and Y have persistent traits of personality -- traits that led them to make different choices under similar circumstances.
So a biography is a compilation of several different kinds of assertions or observations: some of the things that happened to the subject, some of the actions and choices the subject made, some hypotheses about the subject's personality and motivational system, and an interpretation of the causes and reasons of some of these choices. The biography asserts a degree of consistency over time -- Mr. X can be counted on to behave similarly in circumstances that raise the same intra-personal issues -- even as it documents the particularity and uniqueness of Mr. X in contrast to other persons in similar circumstances. So a biography combines particularity and a certain kind of generality.
Now consider a textbook in personality psychology. The textbook too is interested in explaining why people behave as they do. But it approaches the problem from the point of view of taxonomy, causal analysis, and generalized explanations. The taxonomy part comes in through the effort to describe a handful of personality "types" -- individuals sharing a cluster of personality characteristics that make them similar in action to each other and different from others. The causal analysis comes in through the door of a set of hypotheses about what constitutes a personality; how features of personality are embodied in the individual; how they are cultivated or shaped through development; and how they manifest in patterns of action. And the generalized explanations enter in the form of statements about groups of people sharing common personality features: "Ethnic massacres often occur as a result of manipulation of group emotions through the media." The task of the theories of personality psychology is to provide a basis for explaining behavior; but unlike biography, personality psychology singles out the common features of personality that are found in a whole group of actors.
Now, if the classification exercise could be done in a really successful way -- so that we conclude that there are personality types A, B, and C, and here are the behavioral dispositions of the three types -- then biography would be unnecessary. All we need to know is whether Mr. X is an A, a B, or a C. In fact, however, we know that people are more varied than this. At best the small handful of personality types associated with personality theory can be construed as ideal types, pure versions of the various hypotheses; but we will also understand that very few people exactly embody exactly one of these ideal types. Instead, people's motivations and personalities are a blend of numerous currents; and the role of biography is to identify these particular confluences in the subject of interest.
This is an interesting contrast for the social sciences, because there is a parallel distinction in the description and analysis of social particulars. Sometimes social scientists are primarily interested in stripping the "individuals" they consider (wars, revolutions, cities) down to a small list of characteristics about which they attempt to arrive at generalizations. And sometimes they are interested in treating the "individual" as a complex particular with its own life history and personality. The urban geographer may want to consider all United States cities with more than 500,000 inhabitants as a group, and then to arrive at some hypotheses and generalizations about this set of cities. This is analogous to the personality psychology of the distinction. Or the urban geographer may want to focus in on the particular identity and persona of one city -- Chicago -- and treat it as a biographer might treat Franklin D. Roosevelt. Both approaches are legitimate. The second, however, is perhaps undervalued in the social sciences because of its particularity. As discussed in the previous posting, however, there are good reasons for thinking that understanding the richness of empirical detail of a city like Chicago is itself a worthwhile sociological task.