The Mind's Inclination Follows The Body's Temperature

Organized around the four elements (earth, water, air and fire), and the four humors (black bile, phlegm, blood and yellow bile), Temperament Theory asserts that these physical qualities determine the behaviour of all created things, including the human body. 

Consider four people who see a star fall to earth. The Melancholic ponders what it means and how he feels about it; the Choleric wants to form an expedition to find it and analyze it; The Sanguine talks about it animatedly to all present;  and the Phlegmatic waits for the others to decide what to do as whatever decision they make is fine by him.