The origins of life present paradoxical meanings for humanity. 1) It is one of the central parts of big history that describes a series of common origins and it is one of the origins that begins a process of enormous diversification. Out of many chemicals comes one cell and then many life forms. 2) The origins of life required bringing together elements and chemicals in enormously complex relationships; this is part of the big history account of increasing complexity. A process of increasing complexity runs from the big bang to the relationships of billions of people within a contemporary digital culture. However, this increasing complexity is by far the exception rather than the rule. Most carbon is not directly part of life forms.
The idea of global, human relationships – of being a citizen of the world – resonates with only some people at best. Given the second law of thermodynamics, we expect increasing disorder; increasing complexity requires increases in availability of energy. Not becoming more complex, or even becoming less complex, is far more common. 3) So far, we have evidence of life originating only once, on Earth, and yet given that the universe is homogenous and isotropic, and we have evidence of thousands of other habitable planets just within our local area of the Milky Way, it must be commonplace throughout the universe. 4) The coming together of sets of relationships produces tenacious life that has persisted for some 3.8 billion years. Yet, some people also perceive how fragile it is, depending on so much for it to continue. Most seem rather unconcerned.
Paradoxical Meanings of Origins of Life
- Common origins Diversification
- Complex, sustained relationships More common to remain unrelated
Life unique to Earth?
- A marvel that it happened at all
Expectation of it being commonplace
- To be expected
- Tenacity of relationships Fragility of life
Initial Discussion of the Themes
In this presentation, I will draw out the paradoxical meaning for humanity from the scientifically verifiable facts about the origin of life. This is part of the effort made by some in big history regarding how to understand our place on Earth and in the universe. The International Big History Association defines big history as “the integrated history of the Cosmos, Earth, Life, and Humanity, using the best available empirical evidence and scholarly methods.” The origin of life is one of the key thresholds or transitions that are commonly listed in works on big history, or the scientifically based narrative of the major steps between the big bang and humanity. (e.g. Brown, Chaisson, Christian, Spier). Since the Miller-Urey experiment in 1952, there has been significant advances in understanding how chemical evolution led to and combined membranes, metabolism, and reproduction in response to the environment. Still, there is not yet consensus on exactly how this occurred some 3.8 billion years ago, much less a replication of the process in a modern laboratory. Big historians who do not hold their degrees in the field of biochemistry look with interest to the accessible work of those who are in that field in order to keep big histories up to date and accurate. I will argue in my presentation that there is a paradoxical meaning in big history for humanity. The first is that it is an account of common origins. The entire known universe began in a single big bang, as far as we know.
On Earth, it appears that all currently existing life forms have descended from a single origin of life; and so far, we have evidence of life only on Earth. Some 3.8 billion years later, a small band of homo sapiens in East Africa seem to have been the common ancestors for all currently living humans. In this regard, we have a scientific basis for our common ground, perhaps even our common good. We often seek an evidence-based reason for unity. On the other hand, after the big bang, there has been such an expansion that our universe perhaps is some 93 billion light years across, although we can only see as far as 13.8 light years from us. Huge numbers of galaxies have long since sped beyond our view. A common big bang goes along with the majority of existence expanding out of view. After the origins of life, an almost infinite variety of life forms developed, many having little to nothing to do with each other. What comfort it is to a antelope having common origins with a snarling lion is unclear. And human cultures have diverged significantly since our ancestors all lived in a small band in Africa; many of them oblivious or hostile to each other. We face evidence of r astounding diversity and ultimate heat death or separation. Exactly how life originated, it involved an incredibly complex series of relationships. The first prokaryote cell was the most complex set of relationships that we know of to the date of its origin in the universe. The theme of increasing complexity is important within big history; we see the development of quarks within protons and neutrons, atomic nuclei with electrons, elements within chemicals, biochemistry to life, increasingly complex life forms, ecosystems and social species, human kinship, villages, cities, nations, empires, and global systems. It is the story of how we got here. Yet, it is incredibly atypical. Vast hydrogen clouds from the big bang exist without any increase in complexity. Vast numbers of prokaryote cells exist today without themselves having become eukaryote cells or any more complex life forms.
Most people seem to exhibit little interest in being “citizens of the world,” must less than of the universe. Increasing complexity is highly unlikely, yet here we are. The universe is homogenous and isotropic. Laws of physics work everywhere. We know now that there are great numbers of habitable planets in the local area of the Milky Way. Throughout the universe, there must be untold numbers of planets with the same chemicals and similar enough conditions to have experienced the origin of life. It must be commonplace. But as Enrico Fermi asked, “So where is everybody?” Not only have we found no evidence for intelligent life, we so far have not found evidence for any life beyond Earth at all. If we find evidence for microbial life on Mars from billions of years ago, we will be ecstatic. Is life a marvelous, one-time occurrence on Earth or is the Universe filled with it? If we find evidence of it having existed on Mars, should our response just be, “Well, of course.”
In the United States, a major political issue is being “pro=life” or “pro-choice.” In big history, it makes little sense to talk about the universe or Earth having been pro-life just because a complex process leading to the origin of life occurred. What we do see is a complex process of chemical evolution that led to life that is impressively tenacious. Life has not only marvellously originated, it has persisted through an oxidation event and now six great periods of extinction. At the same time, we are worried by how fragile life is; how it depends on a huge number of “Goldilocks” conditions to survive. Awareness of the complexity of what was required for life to have originated – and survived – has led many to greater commitment to protecting it. A paradox is that even more people seem quite uncommitted to any such goal.