Biology and Spirituality, part 1

from “Song of Myself”
Walt Whitman

I celebrate myself, and sing myself,
And what I assume you shall assume,
For every atom belonging to me as good belongs to you....
My tongue, every atom of my blood, form’d from this soil, this air....

The past and present wilt—I have fill’d them, emptied them,
And proceed to fill my next fold of the future.
Listener up there! what have you to confide to me?
Look in my face while I snuff the sidle of evening,
(Talk honestly, no one else hears you, and I stay only a minute longer.)
Do I contradict myself?
Very well then I contradict myself,
(I am large, I contain multitudes.)
I concentrate toward them that are nigh, I wait on the door-slab.
Who has done his day’s work? who will soonest be through with his supper?
Who wishes to walk with me?
Will you speak before I am gone? will you prove already too late?
Where do we come from? What are we? Every human culture addresses these questions in some way. Origin myths are part what makes a people a people. What is ours? For Unitarian Universalists today, it’s a story informed by science, which means it is continually revised. Still, we are a faith tradition, not a scientific association.

Where do we come from? What are we? Answers of Unitarian Universalists are many and various and not all consistent. To paraphrase Whitman: Do we contradict ourselves? Very well then we contradict ourselves. We are large. We contain multitudes.

Our faith tradition, informed by science, reaches beyond science in two regards. First: awe, wonder, mystery, transcendence. The first of the sources of the living tradition we share articulated in the Unitarian Universalist Association bylaws is:
“Direct experience of that transcending mystery and wonder, affirmed in all cultures, which moves us to a renewal of the spirit and an openness to the forces which create and uphold life.”
We look to science to inspire some transcending mystery and wonder – and scientists themselves often feel a sense of mystery and wonder evoked by their explorations – but if they speak of it, they are then speaking not as scientists but as simple human beings.

Second: meaning. The fourth principle of Unitarian Universalism declares our "covenant to affirm and promote a free and responsible search for truth and meaning." Science gives us our best current guess about what is true about the way our world may operate in predictable ways – while teaching, also, a humility of understanding that no truth is final and settled. But meaning – what science’s findings mean for who we are, for the ethics and values that guide our life, for the purposes we may construct for being alive – that is beyond the purview of science itself. We can use scientific findings in the construction of meaning of our lives, but that construction is not itself science’s job.

Science inspires our spiritual lives the way science may inspire poetry. Poets draw on science as Whitman did when he wrote: “Every atom belonging to me as good belongs to you.” As spiritual people -- which is to say, people confronting transcendent mystery and wonder and seeking the meaning of and to our lives -- we draw on science in the way poets sometimes do.

And we ask: What is our place in the grand order of things? For instance, are we alone in the universe?

There are an estimated 100 billion stars in the Milky Way galaxy. If we are very generous and assume 10 planets per star, that gives us a trillion planets in our galaxy. And there are perhaps about 200 billion galaxies. Surely in all that vastness this pale blue dot we call Earth can’t be the only place where life appeared.

Well, let’s think through what the barriers are to the development of life. First, habitability. A habitable planet would be one with liquid water and most of the planets out there are either too hot or too cold. A very rough but plausible estimate would be one in a thousand planets are habitable. If one in a thousand are habitable, then 1 trillion planets means 1 billion habitable planets out there.

The next barrier is stability: it has to have a climate that stays benign over eons. It’s quite difficult to get that much stability because astronomical forces tend to push a planet towards freezing or frying. Our moon – unusually large for a planet our size, and just the right distance away -- gives Earth a stable axial tilt and a slow rotation rate – which helps us have a more-or-less stable climate. Maybe one in a thousand planets in the habitable zone have long-term climate stability. Now the billion planets is down to a million.

As scientist and writer Stephen Webb looks at the remaining barriers to the sort of sophisticated technological life that humans have developed on Earth, he continues to use the very rough guess of about one planet in a thousand making it through each barrier. He says:
“Life must start -- the million becomes a thousand. Complex life forms must arise -- the thousand becomes one. Sophisticated tool use must develop -- that's one planet in a thousand galaxies. To understand the universe, they'll have to develop the techniques of science and mathematics -- that's one planet in a million galaxies. To reach the stars, they'll have to be social creatures, capable of discussing abstract concepts with each other using complex grammar -- one planet in a billion galaxies. And they have to avoid disaster -- not just self-inflicted but from the skies, too. That planet around Proxima Centauri, last year it got blasted by a flare. One planet in a trillion galaxies.” ("Where Are All the Aliens?" 2018)
But our best guess is that there probably are only 200 billion galaxies. So, Stephen Webb concludes, “I think we’re alone.”

This is a rather disappointing conclusion. I love to imagine other star-faring civilizations out there – but as best we can guess, the probability of that is, sadly, low. Very simple life, though, according to Webb’s rough estimations, may well be on about a 1,000 planets in our galaxy alone – but it’ll be single-celled prokaryotes.

Prokaryotes may have started here on Earth as soon as 3.5 billion years ago. But the jump from prokaryotic life to eukaryotic is a huge jump. Stephen Webb simplifies his calculation by assuming that each of the successive barriers he lists is cleared by one out of every thousand planets that had cleared the previous stages. But from what I’ve gathered, it’s really that jump from prokaryotic to eukaryotic that’s the big one.
As Ed Yong writes,
“For roughly the first 2.5 billion years of life on Earth, bacteria and archaea [the two forms of single-celled prokaryotes] charted largely separate evolutionary courses. Then, on one fateful occasion, a bacterium somehow merged with an archaeon, losing its free-living existence and become entrapped forever within its new host. That is how many scientists believe eukaryotes came to be. It’s our creation story: two great domains of life merging to create a third, in the greatest symbiosis of all time. The archaeon provided the chassis of the eukaryotic cell while the bacterium eventually transformed into the mitochondria. All eukaryotes descend from that fateful union.” (I Contain Multitudes 9)
Eukaryotes include all the animals, plants, fungi, and algae. Thus, every animal, plant, fungus, and algae emerged from that one highly improbable fluke. An archaeon absorbed a bacteria and somehow they both survived it, and lived on as a conjoined organism. It was still single-celled, at first, but now it was a cell with a nucleus, surrounded by mitochondria, each with its own distinct DNA. This changed everything. The bacteria part, the mitochondria, provided an extra source of energy, allowing cells to get bigger and become more complex.
“There’s a huge void between the simpler cells of bacteria and archaea and the more complex ones of eukaryotes, and life has managed to cross that void exactly once in four billion years. Since then, the countless bacteria and archaea in the world, all evolving at breakneck speed, have never again managed to produce a eukaryote. How could that possibly be? Other complex structures, from eyes to armor to many-celled bodies, have evolved on many independent occasions, but the eukaryotic cell is a one-off innovation. That’s because, as [biochemists] argue, the merger that created it – the one between an archaeon and a bacterium – was so breathtakingly improbable that it has never been duplicated, or at least never with success.” (I Contain Multitudes 9-10)
Once – in four billion years. Scientists in laboratories haven’t been able to come close to getting an archaeon to absorb a bacterium and have them survive together – yet somehow it happened.

We’ll pick up from there in part 2.

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