Thursday, May 28, 2015

The universe across eight thresholds of complexity

David Christian discusses Big History at Here's some of that discussion. Since he identifies eight (8) thresholds I've inserted numbers in brackets to help identify them:
We tell it—this is just a convenience—across eight thresholds of increasing complexity. [1] The first is the Big Bang itself, the creation of the universe. [2] The second is the creation of stars. Once you have stars, already the universe has much more diversity. Stars have structure; galaxies have structure. You now have rich gradients of energy, of density, of gravity, so you've got flows of energy that can now build more complex things.

[3] Dying stars give you the next threshold, which is creating a universe with all of the elements of the periodic table, so it's now chemically richer. You can now make new materials. You can make the materials of planets, moons, and asteroids. On some planets, particularly rocky planets, you get an astonishing chemical diversity....

Life is a [5] fifth threshold; planets are a [4] fourth threshold. One of the wonderful things about this story is that, as you widen the lens, I'm increasingly convinced that all these very big questions that we're asking that seem impossible when seen from within the disciplinary silos begin to look manageable from the large scale. Let me give two examples. One is life itself.

I have a feeling that within this story it's possible to offer a fairly simple but powerful definition of what makes life a different level of complexity from the complexity of, say, simple chemical molecules or stars, or galaxies. With life, you get complex entities appearing in extremely unstable environments. Stars create their own environments so that they can work mechanically. If you have complex things in very unstable environments, they need to be able to manage energy flows to maintain their complexity. If the environments are constantly changing, they need some mechanism for detecting changes. That is the point at which information enters the story.

What were just variations in the universe suddenly become information, because something is responding in a complex way to those variations. Something like choice enters the story because no longer do living organisms make choices mechanically; they make choices in a more complex way. You can't always guarantee that they're going to make the same choice. That's where natural selection kicks in.
And now we seem to have a slip in the numbering:
If you move on to human beings ( [5] our fifth threshold of increasing complexity) you can ask the question, which students are dying to ask: What makes humans different? It's a question that the humanities have struggled with for centuries. Again, I have the hunch that within this very broad story, there's a fairly clear answer to that. If all living organisms use information about their environments to control and manage the energy flows they need to survive—biologists call it metabolism—or to constantly adjust—homeostasis—then we know that most living organisms have a limited repertoire. When a new species appears, its numbers will increase until it's using the energy that its particular metabolic repertoire allows it to fill.

Yet look at graphs of human population growth and something utterly different is going on. Here, you have a species that appears in probably the savanna lands of East Africa, but it doesn't stay there. During the Paleolithic—over perhaps 200,000 years—you can watch the species, certainly in the last 60,000 years, slowly spreading into new niches; coastal niches in South Africa. Blombos Cave is a wonderful site that illustrates that. Then eventually desert lands, forest lands, eventually into ice age Siberia, across to Australia. By 10,000 years ago our species had spread around the world.

This is utterly new behavior. This is a species that is acquiring more, and more, and more information. That is the key to what makes us different.
At this point I'm going to switch over to the website for The Big History Project and just list the rest:

[6] Collective Learning: How humans are different.

[7] Agriculture: How farming sows the seeds of civilization.

[8] The Modren Revolution: Why change accelerates faster and faster.

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From time to time I've taken a somewhat different look at the big picture. For example:

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