The four temperaments

Four temperaments is a proto-psychological theory that suggests that there are four fundamental personality types, sanguine (enthusiastic, active, and social), choleric (short-tempered, fast, or irritable), melancholic (analytical, wise, and quiet), and phlegmatic (relaxed and peaceful). Most formulations include the possibility of mixtures of the types.

The Greek physician Hippocrates (c. 460 – c. 370 BC) incorporated the four temperaments into his medical theories as part of the ancient medical concept of humorism, that four bodily fluids affect human personality traits and behaviors. Later discoveries in biochemistry have led modern medicine science to reject the theory of the four temperaments, although some personality type systems of varying scientific acceptance continue to use four or more categories of a similar nature.

Temperament theory has its roots in the ancient four humors theory. It may have origins in ancient Egypt or Mesopotamia, but it was the Greek physician Hippocrates (460–370 BC) who developed it into a medical theory. He believed certain human moods, emotions and behaviors were caused by an excess or lack of body fluids (called "humors"): blood, yellow bile, black bile, and phlegm. Next, Galen (AD 129 – c. 200) developed the first typology of temperament in his dissertation De temperamentis, and searched for physiological reasons for different behaviors in humans. He classified them as hot/cold and dry/wet taken from the four elements. There could also be "balance" between the qualities, yielding a total of nine temperaments. The word "temperament" itself comes from Latin "temperare", "to mix". In the ideal personality, the complementary characteristics or warm-cool and dry-moist were exquisitely balanced. In four less ideal types, one of the four qualities was dominant over all the others. In the remaining four types, one pair of qualities dominated the complementary pair; for example, warm and moist dominated cool and dry. These latter four were the temperamental categories Galen named "sanguine", "choleric", "melancholic" and "phlegmatic" after the bodily humors, respectively. Each was the result of an excess of one of the humors that produced, in turn, the imbalance in paired qualities.

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