I must say I have never found a use for this scheme of psychological functions, and this is because function typology sets out to define different people's mental make-up--what's in their heads--something which is not observable, and which is thus unavoidably subjective, a matter of speculation, and occasionally of projection. A good example of the difficulties such guesswork can introduce is the way in which Jung and Myers confound introversion with intuition, saying that the introverted types are the ones "interested in ideas and concepts," while the extraverted types are "interested in people and things." In my view, which is based on close observation of people's use of words, the intuitives are the ones primarily interested in in ideas and concepts, while the sensing types are those primarily concerned with concrete things. Indeed, after forty years or so of typewatching, I have not found any SPs or SJs who were more inclined to discuss conceptual matters (abstractions), than to discuss factual matters (concretions). The sensing types are more perceptual than conceptual, while the intuitive types, NFs and NTs, are more conceptual than perceptual.