Why Is The Universe Complex?

We live in a stunningly complex universe.  Stunningly, we do not know why or how. In the next series of blogs I intend to do my own best to explore this issue. It is of the deepest importance to understanding our world and ourselves.

I do not know how much progress you and I can make.

We’ll see.

Let’s begin where the physicists start. In the Standard Model of particle physics and General Relativity there are about 23 “constants of nature.” These are numbers, often measured to high precision, that are put in “by hand” into the equations of physics to get them to describe our universe.

Physicists claim that these 23 constants of nature must be finely tuned to nearly exactly the values they have in order for our universe to be complex.  Were the values very different we would not get stars, galaxies, complex atoms, chemistry, or life.  We might get a universe that flashed into existence for an instant then disappeared. Or we might get a universe that expanded so rapidly that all that would exist would be hydrogen in a starless empty space.

I want to make two initial points in this first blog on the subject:  
First, and critically to the subject of these blogs, the fine tuning of the constants of nature are at best a necessary condition for the universe to be complex. They are absolutely not yet a sufficient account of “why the universe is complex,” the main  purpose of these efforts.

Second, we face the profound issue of “why” the constants of nature are so finely tuned. Since we have, at present, no THEORY for the values of these constants, put in by hand, physics has the following choices:

  1. God tuned the constants of nature.
  2. If the values of the constants were very different, life would not have evolved, so physicists would not have evolved to wonder why the constants of nature are what they are.  This idea has led to the postulate that we live in just one of vastly many universes, a “megaverse”, the constants of nature have different values in different universes, and we happen to be lucky enough to be in a universe with the “right” values of the constants of nature.  This view is called “The Weak Anthropic Princiiple.” The term, “Anthropic” stands for the fact that we live in a universe where life and physicists could evolve.  A fine discussion of this view is in Leonard Susskind’s The Cosmic Landscape.
  3. Our one universe somehow evolved the values of its constants, and perhaps its very laws, such that the universe we live in is the only universe and is complex.  I want this view to be true.   For it to be true, there must be processes by which the laws and the values can both evolve.  I hope to discuss this in later blogs.


I return to the primary question of these blogs: Why and how did the universe become complex?  And I make a final point in this short blog.  Eric Chaisson, a Tufts University physicist, in Cosmic Evolution has shown convincingly that the energy density per gram tissue per second increases in cosmic evolution, for example in stars, in the evolution of life and in the evolution of or cultures.  The data look convincing.  Now energy per unit time is power, so Chaisson is talking about a power density per gram increasing in cosmic evolution.

I take Chaisson’s data, and ask: How in the world might that increase in power density have occurred? We’ll start trying to answer this in subsequent blogs.

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