Empedocles, in his Tetrasomia, was the first to propose four elements, fire, earth, air, and water, which he called the four “roots” (ῥιζὤματα, rhizōmata), and Plato seems to have been the first to use the term “element (στοιχεῖον, stoicheion)” in reference to them. These were the ideas of philosophers rather than experimental scientists in the modern system. Still, the writings of Aristotle perpetuated this system for almost two thousand years and because of this the classic four elements of Earth, Air, Fire and Water played an integral role in alchemy. The concept of elements could be said to have given rise to one of the most fundamental ideas of later alchemy. This was the principle that the properties of a substance depend on what it is made of. This in turn led to the concept that altering the properties could transform the substance, the basis of the operations of alchemy.
Michael Sendivogius (1566–1636) was a Polish alchemist, philosopher, and medical doctor. As with many akchemists he worked on the practical side and developed ways of purification and creation of various acids, metals and other chemical compounds. He discovered that air is not a single substance and contains a life-giving substance, 170 years before the scientific identification of oxygen. His writings reveal the way the alchemists viewed the Four Elements. “There are four common elements and each has at its center another deeper element which makes it what it is. These are the four pillars of the world. They were in the beginning evolved and molded out of chaos by the hand of the Creator; and it is their contrary action which keeps up the harmony and equilibrium of the mundane machinery of the universe; it is they, which through the virtue of celestial influences, produce all things above and beneath the earth.” The “deeper element” is the archetype and “chaos” is of course the the Prima Materia.
To the alchemists, the Four Elements are those fundamental archetypes within matter and are symbolic of their metaphysical qualities. According to Empedocles, Fire and Air are “outwardly reaching” elements, reaching up and out, whereas Earth and Water turn inward and downward. In his view, and that of later alchemists, the elements are not only material substances but also spiritual essences. As archetypes, the elements must be experienced to be understood. Empedocles associated each element with a god, as a way to express this. “Hera rules the fruitful earth,” he wrote. “Hades the central fire, Zeus the luminescent air, and Persephone the mollifying water.”
Aristotle (350 BC) further developed the theories of Empedocles by explaining them in terms of their qualities. In his view, the elements arose from the interplay of the ideal (or archetypal) properties of hotness and coldness, and dryness and wetness. Fire (dry and hot) and Water (wet and cold) are polar opposites, as are Earth (dry and cold) and Air (wet and hot). Wet and dry are the primary qualities. Wet (moistness) is the quality of fluidity or flexibility, which allows a thing to adapt to its external conditions, whereas Dry (dryness) is the quality of rigidity, which allows a thing to define its own shape and bounds. As a consequence Wet things tend to be volatile and expansive, since they can fill spaces in their surroundings, whereas Dry things are fixed and structured, since they define their own form. Aristotle predicted that one material could be transformed into another by altering the mix of its archetypal elements and their qualities.