The document discusses the type and trait approach to understanding personality, specifically referencing a Greek physician Hippocrates' classification of individuals into four types based on the dominance of internal fluids or humors - blood, phlegm, black bile, or yellow bile. Each fluid was associated with a particular temperament - blood with a sanguine or cheerful and active temperament, and phlegm with a phlegmatic or apathetic and sluggish temperament. This classification approach suggests personality is determined by the dynamic organization of an individual's psychophysical system and its unique adjustment to the environment.