In many ways, Empedocles synthesizes the thought of the previous Presocratic philosophers, as well as various ideas from the mythopoetic tradition. He attempts to present a theory that will reconcile various conflicting but convincing explanations of the cosmos. Thus he writes with a self-consciousness of his place within an ongoing search for true understanding.
Drawing on the mythopoetic tradition, Empedocles postulates that the cosmos is held in harmony by Love. Hesiod in his cosmology had previously written that Eros unites Chaos. Now Empedocles states, "And these never cease continually interchanging, at one time all coming together into one by Love and at another each being borne apart by the hatred of Strife" (Curd, 83). Empedocles thinks that there are two forces in the world: one that unites and one that divides. He also argues that these two forces are necessary. Using language like that of Parmenides, he says, "For they are as they were previously and will be, and never...will endless time be empty of both of these" (Curd, 83). Hence Love and Strife are eternal drives that are ungenerated and imperishable in Empedocles' theory.
Moreover, Empedocles incorporates the material monism of Thales, Anaximander, and Anaximenes in his theory. He explains, "For at one time they grew to be only one out of many, but at another they grew apart to be many out of one: fire and water and earth and the immense height of air, and deadly Strife apart from them, equal in all directions and Love among them, equal in length and breadth" (Curd, 84). Thales had thought that all of the material world consisted of water. Similarly, Anaximander thought that it was boundless matter. Anaximenes in turn believed that air was the substance of the material world. However, unlike them, Empedocles argues that these elements are like roots in the cycle of Love and Strife, the combination of which causes all material things appear.
Additionally, Empedocles wants to resolve the apparent contradictions raised by Heraclitus. Heraclitus had stated that unchanging change is a feature of reality, that out of unity comes plurality, and that, just as we do and do not step into the same river, we both are and are not. Empedocles says of Love and Strife that "they never cease interchanging continually, in this way they are always unchanging in a cycle" (Curd, 83). He thinks that there is an unchanging tension between the unifying and dividing forces that causes continual change. He also addresses a necessity pointed out by Parmenides, who claimed that what-is cannot increase or decrease. Empedocles says, "None of the whole is either empty or overfull" (Curd, 82). It seems likely that he thinks that his cosmological cycle is whole. This seems to follow from the notion that the the tension of Love and Strife is ungenerated and imperishable. Although this tension causes change, the cycle is itself whole and unchanging. Hence the underlying cause, the cycle, does not increase or decrease as it undergoes its continual revolutions.
Empedocles draws on the ideas of his time to formulate an extensive theory to explain the cosmos. He seems to be aware of the necessities and problems presented by other philosophers before and contemporaneous with him. He attempts to resolve apparent contradictions while also keeping with established theories. Empedocles builds on the best ideas of his time to create something new and original. It will be interesting to see how his ideas ultimately contribute to the ongoing search for truth in Presocratic philosophy.