Ideographic and nomothetic apporaches in psychology

The tension between ideographic and nomothetic approaches in the psychology of the 20(th) century is discussed from a methodological point of view. It is pointed out that some so-called general laws in psychology contain hidd en individual parameters (e.g., the Weber-Fechner law of psychophysics), an d that often they are not as universal as many believe. As Lewin observed, they describe laws at the level of person aggregates, and drawing inference s from the aggregate level to the individual level can be misleading. This applies not only to mean trends but also to correlations between persons, t hus to personality psychology. Stern's and Allport's critique of the differ ential-psychological approach to individuality is contrasted with two recen t attempts of enriching nomothetic approaches with idiographic data: person -centered analyses of personality types and multi-level analyses of individ ual functions. It is concluded that idiographic and nomothetic approaches c an be fruitfully combined, and that there are practical rather than theoret ical limits to making psychology more idiographic than it has been in the 2 0(th) century.