In 250 words or less.
One of my favorite Terrence McKenna raps talks through the evolving complexity of the universe. here's a sample (longer McKenna transcript here):
Out of atomic systems come chemical systems. Out of chemical systems comes the covalent hydrogen bond, the carbon bond, complex chemistry that is pre-biotic or organic. Out of that chemistry comes the macro-physical systems that we call membranes, gels, charge transfer complexes...this sort of thing. These systems are the chemical pre-conditions for life. Simple life, the life of the prokaryotes, the life naked un-nucleated DNA that characterized primitive life on the planet.
Out of that life come eukaryotes, nucleated cells and then complex colonies of cells, and then cell specialization - leading to higher animals, leading to social animals, leading to complex social systems,
I get from this a sense of precipitation. Energy, matter, form, biology, culture all precipitate from this cooling entity we call the universe. I think this has deep implications for the evolution of biology and the evolution of culture across the universe.
Think of this. An ocean, teeming with bits. We are some of those bits. One day (one cosmic aeon, choose your term), we wake up in a rock pool. The ocean level has gradually settled and we are now in a discrete region.
We float in the water, perhaps climb on the walls a bit but in a few more days, some of us start to wonder how we got here. What event caused us to be created in this pool. We measure the parameters of this pool, it is a wonderful pool just fit for our habitation. Some of our bravest swim all the way to the bottom of the pool and dig around. They find strange, ancient material and we develop a theory that our biology grew from the bottom of the pool upwards.
Some of our craziest begin to wonder if there are other pools. If there are other pools, are there also other beings like us? Are the unique, possibly random events that led to our existence availble in those other pools? Did beings like us also emerge from the bottom of their pools? Would they look like us?
Others decide that is there are other pools, there's probably lots of cool stuff in them, so we better get there first. They develop the technology to see outside our pool and gradually build craft that can hop over the wall and send back messages. We find other pools.
So you can see where this is going. The emergence of life on Earth wasn't the result of a unique event, building up from a set of specific environmental criteria leading to the current wave of genetic activity.
No, it's the reverse. We are living in a discrete pool of material, separated from other similar pools only by time, space and gravity. Because biology exists on earth, we can know that it exists elsewhere, because we are no more than a part of the gradually cooling muck of the cosmic orogony.
Certainly, I invoke some poetic license in this.
There's an interesting span where maybe occasional bits othe ocean splash over into our rock pool, and sometimes one or two of us are swept out and back in again. But that's a different post, don't want to get on an unintended tangent.
Another unintended tangent would be the few who never forgot that once there was a space where 'space' did not exist.