The disciples of Thales and Pythagoras grant that all bodies are passible and divisible into infinity. Others hold that atoms and indivisible parts are there fixed, and admit not of a division into infinity. Aristotle, that all bodies are potentially but not actually divisible into infinity.
The ancient philosophers held that the mixture of elements proceeded from the alteration of qualities; but the disciples of Anaxagoras and Democritus say it is done by apposition. Empedocles composes the elements of still minuter bulks, those which are the most minute and may be termed the element of elements. Plato assigns three bodies (but he will not allow these to be elements, nor properly so called), air, fire, and water, which are mutable into one another; but the earth is mutable into none of these.