Here's one article that made me think about it:
Even before reading that, I had lately been thinking about how diversity is the condition for the greatest forms of unity. An illustration: what is more one, a cup of water or a man? Now certainly the water is more uniform in its constitution, whereas man is made up of so many diverse parts which are sometimes more less essential. Yet the man has a unity which the water does not. You can take a cup of water and divide it in two without having changed it very much--you could put the parts back together and it would be as if nothing happened. Man on the other hand has such a unity that if you cut something off, it will probably not attach as easily and (depending on what you cut off) it might make that man cease to be a man altogether.
It's interesting that the greatest mysteries of the Faith also involve unity, not unity without distinction, but a higher sort of unity. I believe in one God. A fairly simple statement. Yet of God I will say The Father is God, the Son is God, the Holy Spirit is God and also The Father is not the Son, the Son is not the Father, and the Holy Spirit is not the Father or the Son. One in essence, one in everything, except that by which they are opposed: relative opposition. This relative opposition is all that distinguishes the persons who are one God.
Then the other great mystery of the Faith: the Incarnation. Jesus Christ is true God and true man, yet he is not two persons on account of this. Jesus Christ is one person who is eternally God and assumed human nature to himself, not such that he was joined to a person distinct from himself, but so that he the divine Word was indeed man without ceasing to be God.
Those are the most extreme cases, where the unity and the distinction are greater than found anywhere else.
Another example where distinction is necessary for unity: producing offspring. Perhaps the most interesting aspect of evolutionary biology is the how the diversity of sexes came to be. If asexual organisms are capable of reproducing without aid from another, why would they change so that diversity of sex would be necessary for reproduction? Similar questions have come to my mind: Is it better to be a plant than to be an animal since you're able to make your own food without moving? Or even as above, is it better to be water since you don't need to eat at all? The answer is probably no. Although being a man is far more difficult than being any other kind of material creature, it is certainly worth the effort.
|Yes, a live-action picture of mitosis|
[I'm skimming Wikipedia as I write this. Found a great quote: "A third theory is that sex evolved as a form of cannibalism. One primitive organism ate another one, but rather than completely digesting it, some of the 'eaten' organism's DNA was incorporated into the 'eater' organism." That's pretty gnarly...]
Having looked at sexuality on merely a biological level, there is also the social level. Skipping person to person friendships (not because they're unimportant), some of the greatest things simply speaking involve the diversity of many members. Three examples: the universe, the state, and the Church. St Thomas argues that the greatest good in the universe is the very order of the universe itself (God is the greatest good outside the universe). Because this includes every creature, but in such a way that each one is fittingly related to every other creature, this will certainly outdo any other order of diverse things to be found in the universe.
The state is another important example. This is hard to see for many, since our government is pretty lame sometimes, etc. But a state is more than its government! It's you and me, and the people who own the grocery store, and the people who work at McDonald's, and the people who start and educate and study and schools. A state is constituted by many persons who all share a common life in some way or another. Whatever problems there are, this order is present and always at work even if you do not notice. I'm not in constant fear of my life. Not because I could take on anyone who came at me with a knife, but because I'm surrounding by people who are formed in virtue (to the extent that they wouldn't do that) and those who would like to do it are dissuaded by the laws and the customs that bring upon them all sorts of unpleasant consequences. Also, if I didn't live in a state, I would have to kill/grow/scavange for everything I ate. Ain't nobody got no time for that. And learning too: I would have to discover everything on my own.
And then there is the Church. This is what is described in 1 Corinthians 12, especially with the image of the Church as the Body of Christ. We started by contrasting the human body with the uniformity of water. This ordered diversity, as it is assumed in Christ, then becomes the image of the unity of the entire community of those in the Church. In a later post, I will go back to considering the kingdom of heaven (especially as in Matthew) and how the descriptions of Christ always involve, not only the God, but also the bad who have a role in the story of the kingdom of heaven. This resolving of the good and evil (which is always involved in the kingdom of heaven) is still distinct from the unity of the members in the body of Christ (who are apostles, prophets, teachers, etc.) and also the unity of the head with the body, of Christ with Church, of a husband and his spouse.
And there's always more... Like friendship. And how this all relates to the mind. And music. And art. And Hegel, "Matter is to gravity as spirit is to freedom." But more later.