images & thoughts \ weekly \ Grabov Rat

the four elements Induction, important as it is in the investigation phase of knowledge acquisition, does not seem to remain when its work is done: in the final form of a systematic scientific knowledge, called "theory", everything ought to be deductive. And systematic approach introduces a hierarchy in the system structure and so-called "elements" in its base. The earliest known imaginative idea of physical science which may be entitled a "theory" was that of the four qualities and the four "elements", usually ascribed to Aristotle (384-322 BC) but traceable in Egypt and India as far back as 1500 BC. Plato considers the elements as being pre-Socratic in origin, from a list created by the Sicilian philosopher Empedocles (ca. 450 BC). Empedocles called these the four "roots". Plato seems to have been the first to use the term "element" in reference to air, fire, earth, and water. A classic diagram according to Aristotle (below) has one square inscribed in the other, with the corners of one being the "elements", and the corners of the other being the properties.

an excerpt from Chemistry by John Read

in What is Science? (J.R. Newman, ed., 1955)

According to this theory, all matter is composed of the so-called "elements": earth, air, fire, and water. Each element, in turn, is pictured as a material embodiment of pairs of fundamental quantities: the hot, the dry, the cold, and the wet. This primitive theory is not to be scorned: the "elements" were selected with discrimination, and the scheme summarizes a great deal of observation and reflection. At an early stage in his intellectual development, man must have been led to discriminate between what we now call the three states of aggregation of matter: the solid, liquid, and gaseous, here represented by earth, water, and air. The fourth "element", fire, stood for what we now term heat or energy.

Let us look into this conception a little further. Water is cold and wet. Heat water and replace the cold quality by the hot one, and the result is a change of water into steam, that is, into a vapor or "air". One "element" has thus changed into another, or undergone transmutation, to use an alchemical term. The fundamental alchemical idea of transmutation is thus implicit in the theory. Nowadays, of course, the process is viewed simply as a change of liquid water through the absorption of heat, or energy, into a gaseous form of the same substance and there is no question of transmutation.

The elemental system used in Medieval alchemy was developed primarily by the Arabic alchemists and based on the Greek four elements. However, in need of transmutation agents, they additionally introduced sulphur and mercury as principles, not elements: sulphur, characterizing the principle of combustibility, and mercury, characterizing the principle of metallic properties. The three principles: sulphur to flammability or combustion, mercury to volatility and stability, and salt to solidity, became the tria prima of the Swiss alchemist Paracelsus. He reasoned that Aristotle's four element theory appeared in bodies as these three principles.