Much excitement followed the recent discovery of new planets. A whole set of planets, at just the right distance from their sun, neither too hot nor too cold for life to prosper. Right now, we can only speculate about the possibility of life on these planets, and I already placed my pessimistic bet: probably not. You are welcome to disagree, and I would like to be wrong on this. In any event, what is exciting is that there is now the very good chance that within my lifetime, we will have some concrete evidence for or against the hypothesis that life exists wherever it can.
Signs of Life
These data will not come from direct visits and collecting samples. Travel across such distances may remain forever beyond human abilities. However, much can be learned from light that is reflected off the planet’s surface. It will tell us whether the planet has an atmosphere, and whether it contains oxygen, or whether there is something else in it that points to life.
If someone would observe us from afar, the presence of oxygen in our atmosphere would give us away immediately. Oxygen is rapidly absorbed and turned into minerals, were it not constantly renewed by plants through photosynthesis. An atmosphere with oxygen or anything like it, anything that cannot be explained by the ordinary chemistry of rocks, liquids and gases would point to the presence of life on a planet.
It’s good to see that people get excited about this kind of discovery, and NASA did an excellent job of spreading the news about it. But here is the real question, the question that should come first: what is life?
The biochemical evidence only points to the presence of life, but it does not really tell us what it is that makes life so very different. Here is one way to answer the question: where there is life, there is true uniqueness of being. A living being is truly one, and it is so in a way that no non-living being can ever be. Think about it: you can split a rock into two, and you have two rocks. But you can’t do the same with a living being. There are exceptions, but you can probably see what I mean, and you can certainly see it when you look at the basic building blocks of life—the living cell. A living being has an organizational unity that cannot be simply cut into two without destroying what is there. This is what make it different from rocks.
You might think that the same is true for atoms or molecules: they, too, become something very different when split into two. But they lack something else: they lack individuality. Any two hydrogen atoms are exactly the same, and any two atoms or any two molecules made by the same arrangement of atoms are exactly alike. There is nothing at all by which we can tell them apart. Atoms and molecules are indivisible unless destroyed, but they are not different individuals. They are exactly the same.
Unity and Individuality
Living beings have both an inner unity that makes them indivisible unless destroyed, but they are also one in the sense that no two living beings are exactly identical. They have unity and individuality. And this is what I find most significant about life: that it gives rise to unique beings, one of a kind and one in themselves. And at the same time, they are also one in the larger sense, one in the unity of all creation, as they all originate in the same origin of all living beings on this planet. But the uniqueness of each living being adds so much to the richness of of what exists on this planet. In each living being, something new begins: a new being.
The medieval Franciscan philosopher Duns Scotus did much to improve our understanding of what it means to be an individual being, an individual exemplar of a species. He emphasized that the essence of each being is not only the essence of its kind, but also the essence of its individuality. He called it “haecceitas,” or “this-ness.” It is what makes one individual this individual, rather than another one of the same kind. When we look at the world at its smallest, the atoms and molecules that make up our world, then individual identity becomes a very fuzzy concept. In the non-living world, there are really only atoms and molecules that keep being rearranged in ever different ways. In life, however, the richness of diversity of being emerges in its fullness. And this is what makes life so important: there is so much of it, and each and every exemplar is something new, a new beginning, and a a new expression of God’s will in all creation.
It would be incredibly exciting if we did found life on another planet. So much would be learned about the origin of life if we saw it begin a second time somewhere. But, as I said at the outset, I rather doubt that we will see it. The uniqueness of life might mean that it happened just once, that the life we see on our planet is all the life that there is in the universe. If it is true, it makes life all the more important, and it tells us all the more of its value. And this is life: the irreplaceable uniqueness that gives value and meaning to creation. Life is what is to be revered in creation, and what gives rise to individual beings, such as ourselves, each of us loved and willed by God.