The terrestrial sphere: the four terrestrial elements

Aristotle's centrality to the established curriculum

As the foremost authority in logic and the three philosophies, Aristotle was the foremost philosophical authority, commonly referred to in medieval texts merely as 'the Philosopher', or 'the master of those who know'. One reason for this status was the indispensable role of Aristotle's logic within the scholastic method. Another was the role of Aristotle's physics in helping to tie the entire curriculum together.

More specifically, Aristotle's analysis of the four terrestrial elements and the fifth celestial element (a fundamental doctrine of natural philosophy)  provided a philosophical basis both for Ptolemaic astronomy (in the quadrivium) and Galenic medicine (in the three higher faculties). The next three images illustrate these key aspects of the received world view which continued to structure the established curriculum throughout our period despite coming under attack from many quarters both in and outside the university. 

The four terrestrial elements

The diagram above, although modern in execution, is ancient in origin. It provides a graphic depiction of the way in which the four terrestrial elements of Aristotelian physics -- earth, water, air and fire -- are generated out of two pairs of opposite qualities: hot and cold, wet and dry.

The locus classicus in which this scheme is explained is in Aristotle's work On Generation and Corruption (bk. II, pts 2-3), which explains that:

Fire is hot and dry;
Air (ἀτμὶς, like vapour) is hot and wet
Water is cold and wet; and
Earth is cold and dry.

Two of these elements (water and earth) are heavy, and seek their natural place at the centre of cosmos. Two of these elements are light and naturally rise away from the centre of the cosmos (fire quickly, air more slowly).

The resulting four elements are very closely associated with the four humours of Galenic medicine.

Alchemists, inquiring more closely into the nature of the four elements, generated alternative explanations of the fundamental constituents of matter, including the Paracelsian tria prima. 

Further reading. G.E.R. Lloyd, Aristotle: The Growth and Structure of his Thought (Cambridge, 1968), ch. 8: 'The Physics of the Sublunary Region', esp. pp. 162-70.

Credits: Howard Hotson (January 2024)