Is the nature of coming-to-be and alteration the same?
Anaxagoras: earth, fire, water, and air are composites, since everything is constructed out of a single element. It follows that coming-to-be and passing-away are the same as alteration, since their substratum remains one and the same.
Empedocles: earth, fire, water, and air are four simple elements. Coming-to-be and passing-away occur when the elements come together (i.e., association) and are dissolved (i.e., dissociation) (but there is no coming-to-be and passing-away of the four elements), whereas alteration is change of qualities. It follows that coming-to-be and passing-away cannot be the same as alteration.
Aristotle argues that Empedocles contradicts the observed fact and himself as well.
