The classical elements (most familiarly earth, water, air and fire), are the basic qualities into which many traditions sort the material world. The four-element scheme runs from the pre-Socratic philosopher Empedocles through Aristotle, who paired them with the qualities hot, cold, wet and dry, into medieval medicine, alchemy, astrology and magic. A fifth, the quintessence or aether, was often added as the heavenly element.
The elements are among the most productive of all the correspondence schemes: signs, temperaments, humours, directions, seasons and much else are sorted under the four, so that the elements become a common language linking many systems.