Saturday, January 8, 2011

A Basic Principle: Equilibrium

My education started with physics.  Though I no longer consider it the only true science, I still think it's an excellent place to start.

If there is one principle from physics that has stuck with me through everything, and which I think can be applied in almost every field, it's the concept of "equilibrium."  I think this idea has long been neglected by philosophers in favor of overly-fashionable, abstruse theories like quantum mechanics and relativity.

In logic, the science of rational thought, all of your most fundamental principles are extremely simple and easy to understand.  For example, "the principle of noncontradiction" simply states that a proposition cannot be both true and false.  It's obvious, yet the philosopher Aristotle built an entire system of thinking based on the idea.

The "principle of equilibrium" (as I call it -- I don't know if anyone has yet thought to name it) is basically this idea:

A system or process is only stable if any slight modification tends to shrink and disappear.

This principle, like the principle of noncontradiction, is easy to understand.  It actually applies in most cases where the word "equilibrium" or "balance" is used.  We say that a person "has his balance" if they can be pushed slightly and remain upright.  Anyone who doesn't recover from being pushed has "lost their equilibrium."

This principle is used everywhere in physics, though rarely in explicit form.  For example, the first question a physicist asks when calculating the structure of a star is: "How does it maintain equilibrium?" or more specifically, "How does the burning of nuclear fuel (outward pressure) balance the gravitational pull of the star on itself (inward pressure)?"  They know that this equilibrium must hold because, otherwise, most stars would either explode or collapse.  In fact, by keeping track of this balance between gravity and nuclear fusion, physicists can calculate with pretty good accuracy when a star will lose it and meet one of those two fates.  (When a star explodes, it's called a supernova.  When it collapses completely, it's called a black hole.)

As I see it, the principle of equilibrium is fundamental to our universe.  I do not mean to claim that all, or even most questions can be answered using this principle.  However, basically everything must obey the principle of equilibrium or fall apart -- especially living systems.  The human body must maintain just the right temperature, just the right saltiness, just the right level of insulin, just the right acidity -- the list goes on and on.  The only reason we manage to live from minute to minute, despite having just eaten 300% worth our daily value of salt in a bag of pretzels, is that our body has evolved countless mechanisms for maintaining equilibrium.  When there's too much acid, the body sets in motion a number of chemical reactions to neutralize it.  Otherwise a bit of heartburn could be fatal. 

Evolution itself is an equilibrium process.  Darwin never put it this way, but the evolution of a species is always a matter of balancing mutation and selection, resources and consumption, births and deaths.  When a species falls out of balance, it either dies out and goes extinct, or spreads without control and causes other species to die out.

I could give an endless list of thinkers or schools of thought that have realized the all-importance of equilibrium, from Lao Tzu, to the Stoics, to early modern astronomers, to chaos theorists.  I could also list and describe in detail many various everyday examples, from boiling water to combustion engines. I could also talk in detail about how to formulate this concept in terms of differential equations.  But my only goal here is to introduce the principle in an intuitive form.  If I've done my job right, you can go think of more examples yourself.

A good strategy you can use is to think in terms of "feedback."  The classic example of feedback we all know is when a microphone is placed too close to one of its speakers.  If you do this, the tiniest noise from the speakers is then amplified to a deafening shriek ("positive feedback").  To maintain equilibrium, the microphone must be far enough away that any noise emitted from the speakers will be quieter next time around ("negative feedback").

From this point of view, the principle of equilibrium simply states that positive feedback leads to instability, and negative feedback to balance. 

Another thing to keep in mind is that many systems display both equilibrium and nonequilibrium properties. Boiling water is a great example of this.  The reason boiling water stays at a constant temperature is that any extra heat given to the water from the stove will simply cause it boil faster, rather than increasing its temperature.  However, this is not a total equilibrium, because more water is boiled away than condenses back in the pot.  You can understand this simply by noticing that we have an equilibrium in temperature, but a disequilibrium in amount of water.

Living things also tend to display a mixed nature like this.  All species, if given enough food, will tend to increase in number exponentially.  (Two bunnies have four bunnies, four bunnies have eight bunnies, etc.)  This is a form of positive feedback, because any small number of creatures will give rise to a great number in a short time.  The reason the world doesn't explode with trillions of bunnies, however, is that there are only so many carrots.  In reality, every wild rabbit has to struggle to find food and survive.  If too many survive, there will be a carrot shortage and the numbers will diminish again.  This is typically how equilibrium is maintained in evolution.  This is an important point to keep in mind through what I'll be discussing later on.  But don't worry if it's not entirely clear yet:  I'll come back to it again and again, each time from a different point of view.

Let me, very quickly, summarize the upshot of these ideas for understanding the problem of "progress."  Modern progress is a massively non-equilibrium process.  It involves exponential economic growth, with -- as the pundits would have it -- no end in sight.  I beg to differ, though.  Most feedback tends to get out of hand rather quickly (exponentially fast, in fact). 

And that's exactly what's happening.  World resource use has skyrocketed at a faster-than-exponential rate for last three hundred years.  Odds are, the end of this spurt of growth will happen sooner rather than later. I'm sure you've seen those graphs showing how the population has shot straight up over the past century.  To make matters worse, resource consumption per person has also been growing exponentially. 

But let's put this in perspective.  Thousands of civilizations have risen and fallen over the last 10,000 years.  When I finally realized that civilization is always a nonequilibrium state (back in November of 2008) it struck me that the cultural dilemma we are facing is far from new.  It would not be a matter of finding some new "radical" solution (we are already drowning in radical solutions) but of rediscovering whatever it is that has allowed peoples and their cultures to regain equilibrium in the past.

In the next several posts, I'm going to review the history of our planet to see what the principles of evolution and equilibrium can tell us about the rise of human civilization 10,000 years ago.

1 comment:

  1. I am loving your blogs! I sat down this morning and made the decision to catch up with all of your blogs, one at a time, one day at a time. But turned out, it's just been too fascinating to stop reading and now I've read the entire thing! It's amazing the journey you took us through, sharing your perspectives of the worlds you were living in. I had no idea the degree of separation in these fields. Your bursts of insights along this journey are incredible! Excited for your next blog! :)