Aristotle posited that the universe consists of two parts
Aristotle posited that the universe consists of two parts: the terrestrial and the celestial regions and that in Earth, all bodies were made up of a mixture of four types of matter: earth, water, air, and fire. He said that other heavenly bodies past the moon were made of a fifth substance, the quintessence of Aether. Heavy or dense objects such as iron were mainly made of the earth while less heavy objects consisted of a mixture of the four elements (Jones, 2010, para. 4).
The basic postulation in Aristotelian physics was that the natural setting of the sublunary matter is rest, i.e. the first three elements must seek their natural place at rest on Earth unless changed by some impenetrable plane, such as a table. The fourth element (fire), resides somewhere above us, but below the Moon. Thus, the air is a combination of air and fire.
