Frederick Copleston, A History of Philosophy, Volume I: Greece and Rome (Westminster: Newman, 1959) 63-64.
Copleston discusses the views of Empedocles, a pre-Socratic Greek philosopher who lived in the fifth century B.C.E.
Ordinarily, I quote from the book that I'm discussing, but here I prefer the Internet Encyclopedia of Philosophy's summary. (Don't worry! A classicist is the one who put together the site. See Empedocles [Internet Encyclopedia of Philosophy].) Here it is:
Empedocles also posits two cosmic forces which work upon the elements in both creative and destructive ways. These he personifies as Love (Philia) - a force of attraction and combination – and Strife (Neikos) – a force of repulsion and separation...What is clear is that these two forces are engaged in an eternal battle for domination of the cosmos and that they each prevail in turn in an endless cosmic cycle. [W]hen Love is completely dominant she draws all the elements fully together into a Sphere in which, although the elements are not fused together into a single mass, each is indistinguishable from the others. The Sphere then, is an a-cosmic state during which no matter can exist, and no life is possible. Then as Love's power gradually weakens and Strife begins to grow in power, he gradually separates out the elements from the Sphere until there is enough separation for matter to come into existence, for the world to be created and for all life to be born. When Strife has achieved total domination we again get an a-cosmic state in which the elements are separated completely and the world and all life is destroyed in a Whirl. Then Love begins to increase in power and to draw the elements together again, and as she does so the world is again created and life is again born. When Love has achieved full dominance we return once more to the sphere.
So Empedocles says that there are two forces: love and strife. Love brings elements together, while strife splits them apart. Both forces played a role in the creation of the cosmos. When everything was combined together into a single mass under the direction of love, there was no life. Consequently, strife needed to separate that mass into distinct elements for life to exist. But too much strife leads to disintegration, which is what Empedocles forecasts for the cosmos. After the universe's disintegration, Empedocles asserts, love will combine the elements into one mass and start the cycle all over again.
Empedocles may have formulated his ideas with other Greek philosophical currents in mind. Copleston narrates that, in the sixth century B.C.E., the philosopher Heraclitus affirmed that the universe is diverse and continually changing, even as there is a divine unity that permeated it. For him, fire was the element underlying the cosmos, but the fire produced a variety of effects, resulting in the orderly universe that is now before us. Although the cosmos has a lot of diverse things that are in tension with one another, such tension maintains a balance that is conducive for order and our survival. "God," for Heraclitus, is this order of the universe, and we should conduct our lives according to this cosmic reason (Copleston 40-43).
In the fifth century B.C.E., Zeno of Elea argued that there is no motion and multiplicity in the universe, for that is merely an illusion. Actually, everything is one, as far as he's concerned (Copleston 58)!
So there seems to have been an issue of unity vs. separation in the philosophy of the sixth-fifth centuries B.C.E. Heraclitus thought that the existence of distinct things in the universe was actually consistent with its order, perhaps because different things could work together by doing their specific roles (compartmentalization). But Zeno may have viewed such a scenario as too messy, so he desired the order of there being only one thing in existence. And Empedocles posited a tension between unity and division, holding that both were assets and liabilities in terms of the creation and maintenance of the cosmos.
As I look at the universe, I see love and strife. Different things work together and contribute to our survival. The inside of a cell, for example, has distinct parts that perform their unique functions and ensure life. At the same time, there is also division and destruction, such as disease, animals eating one another, etc. And yet, paradoxically, even that division and destruction contribute to order. Animals eating one another can prevent the overpopulation of one animal group, etc.
In terms of Christian ethics, God created us different, yet he wants us to love one another, to see ourselves as somehow united with other human beings. Within the body of Christ, there are Christians with different spiritual gifts, yet they are all part of one body. Paul points out that a human body has different parts that help it to carry out its functions, and he likens that to the local church: diverse people work together in unity for a common purpose (I Corinthians 12).
My reading today reminds me of Madeleine L'Engle's A Wind in the Door. See A Wind in the Door for my comments. In that book, L'Engle encourages people to be themselves--authentic. Yet, she also points out that total autonomy and selfishness are a path to destruction. For her, there should be diversity and unity. So I guess she would agree more with Heraclitus, assuming I defined his position correctly!