
The three elements of nature, according to Heraclitus: earth, water, and fire, aka the three element theory.

The three elements of nature, according to Heraclitus: earth, water, and fire, aka the three element theory.

In science, three element theory asserts that the universe is comprised for three primary elements, namely: earth, water, and fire, and that among these fire is the fundament or underlying essential nature of earth and water.

Overview
The three element theory was introduced by Greek philosopher Heraclitus, in circa 500BC, supposedly derived in some way from the Egyptian Heliopolis creation myth, according to which the universe resulted from a primordial abyss from which fire (Ra) burst forth thereafter self-engendering earth (Geb) and water (Nun). [1]

Four elements
In c.450BC, Empedocles added "air" to the previous three elements, therein making the four element theory.

See also
● Two principles
● Three principles

References
1. Luckert, Karl. (1991). Egyptian Light and Hebrew Fire: Theological and Philosophical Roots of Christendom in Evolutionary Perspective (§:Heraclitus, pgs. 206-). SUNY Press.

Further reading
● Kahn, Charles H. (1981). The Art and Thought of Heraclitus: a New Arrangement and Translation of the Fragments with Literary and Philosophical Commentary (three-element theory, pg. 154). Cambridge University Press.