Abiogenesis
There is no natural progression from the absence of numbers to “one”. I don’t mean zero. It is possible to get from zero to one; it might take an infinity, but the logic of the numberline permits it. The real problem is that there is no incremental progress between an absence of numbers and their existence. It is impossible to build towards the concept of “one”, gradually. What about life? Is it possible to get from “no life” to “life”? Or is the logic as ungiving as the philosophy of the numberline? Unlike numbers life after all is material. The answer feels like it should be simpler. It feels like a progression should be possible. Given matter, that is molecules and the right chemical conditions, will “life” emerge? Stated in the affirmative this is the theory (and study) of “abiogenesis”.
At this stage, it is important to clarify, that this is in no way a question about God, or creation. Or at the very least, it doesn’t have to be. There is always room for a little bit of God either way, if you feel like it. Even if matter can self-assemble into living cells, the question of why it happens, to what purpose, remains, and God is back on the agenda. For those who prefer even more God than that, there are theological interpretations for conscious and unconscious life and so forth. My point is simple: if you experience existential anxieties, these will not be settled by whether or not “abiogenesis” is possible. But it is one heck of a proposition!
The art of good science is about finding the right question to ask. A good question has a logical answer, leaves little room for misinterpretation and lays bare its assumptions. So for a discussion on “abiogenesis” I would propose this: “In the absence of divine intervention, is it possible to find a set of chemical conditions, which will give rise to cellular life?” In what follows, I expand a little on the premises of the question, and do my best to arrive at an answer.
“In the absence of divine intervention” — I am not assuming there is no God, just that perhaps she was busy at the moment matter came alive, or will be looking away when we, humans have a go at genesis in a test tube.
A focus on “cellular life”
The theory of Abiogenesis has its roots with Aristotle, who believed in “spontaneous generation”. Aristotle believed that life sprung out of other life, so that bees were created out of flowers and maggots from decaying flesh. Aristotle’s genius is not to be questioned. He used his tools to the best possible assessment of the world around him. His tools were his eyes. He watched maggots consume dead flesh, bees fly towards flowers and he inferred that life produced more life, spontaneously. He lacked the tools that would have allowed him to see that while life is a pre-requisite for other life, generation is not spontaneous.
If Aristotle had a microscope, he would have seen that generation requires reproduction, and begins at a cellular stage. This may seem like a simple statement today, but it is only simple because it rests on innumerable observations over the centuries that have passed since Aristotle’s time. Here is the view from where we stand today*. We have good reason to believe that all life on our planet is cellular, it is encoded for by DNA, a code we call “universal” because it translates into similar molecular messages across the lifeforms we have studied, and it evolved gradually from a common unicellular ancestor LUCA (or last universal common ancestor). Possibly a thermophilic bacterium living by a hydrothermal vent in the middle of the ocean.
[*It is possible that there is something else entirely out there, tucked away in a corner of the universe. So let’s not lose creative steam here, just acknowledge the limits of what we know and set aside the “unkown unknowns”.]
If something like LUCA was the first cell on Earth, that gave rise to all subsequent life, the question at the heart of modern abiogenesis is really to ask if we can create a synthetic cell in a test tube.
“…is it possible to find a set of chemical conditions…”
Is it possible to find a set of chemical conditions, apply them on a random soup of molecules that would give spontaneous life to something resembling LUCA? I would have to go with “No”. There is a wide array of theories about how LUCA came to be, for example starting with self replicating RNA molecules that existed in a primordial soup heated by intense sun radiation in the absence of oxygen. But even if they are historically plausible (which many are), a re-inactment in a test tube is beyond the aspiration of biologists. It would of course also be the only hard proof. The odds are too slim and the hypotheses too far fetched to merit the investment of time and energy to prove them. It also appears that time is an essential ingredient to the process, so abiogenesis from random matter over the course of an experiment (which is inevitably short) is impossible under these premises.
However, biologists have come a long way towards designing and modifying existing cells. Scientists led by J. Craig Venter have gone so far as removing all genetic material from an existing cell and replacing it with synthetic DNA (manufactured in vitro), without killing the organism. The resulting healthy, reproducing living bacterium cell, lovingly referred to as Syn1.0, contains no original DNA, so is “synthetically designed” based on parts (genes) of known function. While this doesn’t fit the strict criteria for “abiogenesis” (the chassis for the synthetic cell is another living cell), it is a hallmark of our current understanding of cellular biology.
The production of synthetic cells in 2010, prompted US President Barack Obama to launch a bioethics review and outraged the Vatican. It is only so long that you can hold onto the premise of a “no God” without running into questions that are larger than life itself.
Here is a link to the Nature editorial on synthetic cells created by Craig Venter’s research team: https://www.nature.com/news/minimal-cell-raises-stakes-in-race-to-harness-synthetic-life-1.19633
