All things in the world were made up of different combinations of these four elements. The elements were affected
by gravity and levity which are the tendency to sink or rise. Aristotle was alive during the Greek empire, and though
his theory was the most poular another man, Democritus had already suggested that all things were made of atoms.
Aristole's theory also relied on to forces:
Harmony casued everything good
Conflict caused everytinhg bad
The heavens were made of Aither, the sacred element.
Aristotles thory whould remain unchallenged until the scientific revolution.