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The Anthropic Principle
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by William H. Keith

After watching a pass of the ISS the other evening, and seeing an episode of “The Universe” about the evolution of the Solar System, I got to talking with a friend about about the Anthropic Principle – the idea that we’re here to see the universe because the universe as we see it is the one that was fit for us to develop, or (alternatively) the universe is the way it is because we’re here to see it.  Since I think best on the keyboard and most of our discussion was on e-mail, I may as well let my webster post the gist of it here as an essay.


Okay... there are four types or levels of the Anthropic Principle as it has been developed so far. They are:

1. Weak Anthropic Principle. Basically, we're here so of COURSE the universe is fine-tuned to our needs. This is a tautology, obviously, which is why it's called "weak." It doesn't explain anything, but merely observes that if the universe was different, we wouldn't be here to say so.

2. Strong Anthropic Principle. States that the eventual emergence of life and intelligence is predestined by the laws and constants of inanimate nature. Again, it doesn't say "why," but observes that conditions seem fine-tuned to make the evolution of intelligence inevitable.

3. Participatory Anthropic Principle. States that observer participation--as suggested by the Copenhagen Interpretation of quantum mechanics [i.e. an observer is necessary to collapse quantum wave functions into a living or a dead cat]--actually shapes the universe for the observers' needs. This is tough to wrap your head around, since we as observers presumably weren't around at the Big Bang.

4. Final Anthropic Principle. States that once life has arisen anywhere in this or any other universe, it will expand exponentially until it is coterminous with the boundaries of the metaverse itself.

These four philosophies are not necessarily mutually exclusive.

One scientist observed that all anthropic reasoning in fact amounted to a fifth level: the Completely Ridiculous Anthropic Principle," or CRAP.

The statement that we must have evolved to fit the existing conditions of this universe is, of course, absolutely correct. It's also valid when considering other possible types of life Out There. A favorite contention of mine in my SF is that OUR kind of life, carbon-based and living on the surface of a planet with liquid water--may be a relative rarity throughout the Galaxy, that the most common forms of life in the universe will be:

1. Critters living in under-ice oceans of tidally heated moons like Europa, or at the liquid-water interface deep in the crusts of internally/radioactively heated worlds like Mars or Pluto.

2. Critters living in the atmospheres of gas giants like Jupiter.

3. Critters living on extremely cold worlds like Triton or Titan, where ice is solid rock and ethane and methane are liquid.

4. Machine intelligences developed by a very large number of alien biological species that evolved and died off billions of years ago. Their progeny has been expanding through the cosmos since.

In the case of the first three, such worlds are FAR more likely to occur than something like Earth, precariously and temporarily balanced in the Goldilocks Zone. In the case of Number 4, the scales of time and space argue against organic life forms inheriting the cosmos. Given the fact that the universe is over 13 billion years old, where Earth itself is only 4.5 billion years old, the chances are far greater that machine intelligences or immortal combinations of organic and machine components are the true inheritors of the universe.

However, the Anthropic Principles go way beyond a simple statement of life evolving to fit its environment. We're talking here about the evolution of a universe that is capable of producing stars or planets in the first place, or of existing long enough for life to form at all.

The Astronomer Royal of England, Martin Rees, addressed this in a book called Just Six Numbers: The Deep Forces That Shape the Universe. Fascinating stuff. He points out that there are six fundamental numbers that shape the cosmos... and slight variations in any one of them would have had a drastic effect on the possibility of life and emergent intelligence. Here they are.

1. N: The ratio of the Electrical Force to the Gravitational Force. The Electrical Force is 10^36 times stronger than gravity. [A child's magnet easily out-pulls the entire Earth.] If gravity were a tad stronger, galaxies would have formed much more quickly, would be much smaller, and they would be so densly packed that it would be tough for stable planetary systems to form. Heat would dissipate faster, stars would age more quickly, and stellar lifetimes would be a million times shorter... hence, no time for the evolution of planets or life.

2. Sigma: The strength of the Strong Force binding protons and neutrons together within the atomic nucleus relative to the repulsive electrical force between positively charged protons. The number works out to .007, and defines the ability of simpler elements to fuse into more complex ones, creating the entire range of elements on the Periodic Table. If the number were .006 instead of .007, protons could not closely bond with neutrons, deuterium would not be stable, and there would be no way for hydrogen to fuse into helium. No stars, and no heavy elements. If Sigma were .008, the natural repulsive force between protons would have been immediately overwhelmed, all protons would have bonded with one another in the first instants of the Big Bang and there would have been no hydrogen left from which to form everything else.

3. Omega: Rate of Cosmic Expansion. If the rate is exactly 1, the universe is flat, and continues expanding at a uniform rate, and possibly, one day in the remote future, slowing to a precisely balanced halt and remaining static. If it is more than 1, the universe is closed and collapses on itself, a closed universe. If less than 1, the universe expands so quickly that galaxies might not have a chance to form, an open universe. The point as it relates to the Anthropic Principle is that Omega is close enough to 1 that the universe has lasted 13.7 billion years without collapsing. Had it been significantly younger with a greater Omega, the universe would have destroyed itself before life could evolve. Even if the universe was 8 - 9 billion years old when it collapsed, there would not have been time for enough first-generation stars to go nova and seed the cosmos with the heavy elements necessary for solid planets. If there were no galaxies, the conditions necessary for new star formation and the dispersal of heavy elements would not have been present. The fact that Omega is so excruciatingly close to 1 seems to be an important factor on the life-friendliness of the cosmos.

4. Lambda: The strength of universal antigravity. This is in opposition to Omega, of course--the recent discovery that the cosmos' expansion is accelerating rather than slowing or remaining static. The force became dominant, overwhelming the universal expansion, about six billion years ago. Had it been stronger, not only the universe but all of matter, down to the last proton, would have torn itself apart long ago, a watershed physicists call "the Big Rip." Even a slightly stronger Lambda might have prevented the formation of galaxies. As suggested above, galaxies are necessary for the evolution of life because pressure waves within the spiral arms trigger new star formation, hence the collapse of stars and the dissemination of heavy elements from the resultant supernovae which go into making new generations of stars and planets.

5. Q: The amount of wrinkling in space, a number defined as 10^-5. Had the primordial fireball been perfectly uniform, smooth, and featureless, with a value smaller than 10^-6, stars and galaxies would never have formed. The entire universe would be a thin, cold, expanding soup of hydrogen. Had Q been larger than 10^-5, the early fireball would have been "lumpy," with areas much larger than galactic clusters [like our Local Group] forming large-amplitude waves inside the fireball that would have collapsed most matter into black holes. Any gas left over would have formed tight, densely packed galaxies not conducive to the formation of stable planetary orbits.

6. D. The number of extended spatial dimensions. We have three of them, though String Theory demands either ten or eleven dimensions, with the extras very, very tightly closed up inside the boundaries of elementary particles. We now think that electrons and photons are 1-dimensional superstrings vibrating within an 11-dimensional matrix. If there were only two extended dimensions, gravity would diminish in direct proportion to distance, rather than by the inverse cube law of three-D. If there were more than three extended dimensions, gravity would be weaker, and planetary orbits would be unstable. Suns might not fuse, planets and stars might not even form.

To these, I would add 7. G, the Gravitational Constant, which I suppose is just another form of N. But quite apart from the electrical force, if the force of gravity were stronger, stars would be smaller, denser, and faster-burning, hence shorter-lived. If weaker, planets and stars might not have formed at all, or fusion might not be possible, so, no stars form.

Current M-Theory, which has arisen out of recent Superstring Theory, provides us with an almost infinite variety of ways and means for the cosmos to assemble itself. Why, then, did we get what we got? Specifically, why these six numbers, at precisely the values necessary for the universe to form as we now see it? So far as we understand things now, there is no reason why ANY of these numbers should not have been something randomly different. The more we look at these numbers, the more we are forced to consider one or more of the Anthropic Principles as a governing or constraining factor.

Now--don't get me wrong. I am NOT a proponent of Intelligent Design--ID--as currently promulgated by folks who want to sneak Christianity in the back door. Virtual energy fluctuations in the vacuum COULD have spontaneously given us the primordial fireball, with no intelligent agent necessary. We don't need a God to explain the universe. And maybe there were a trillion trillion trillion universes that came into existence randomly and went nowhere before one--ours--happened by chance to get all six numbers right and produce us.

But when I'm thinking Big Thoughts, as I'm wont to do occasionally, I consider the following:

Physicist Frank Tippler has hypothesized a moment he called the Omega Point at the end of time, when all available light paths [hence information] would be available as the universe fell together in the Big Crunch. That was written before we discovered Lambda, of course. We now know there will be no Big Crunch. But the principle remains: in ten billion years' time--or 100 billion years or even more--might intelligence have evolved to the point where it could create new universes for itself, thereby escaping the Doom of entropy? And in so doing, would it deliberately instill constraints on the way the new universe evolved to maximize the chances for life and intelligence to evolve there?

Or might they create a new universe with such constraints in order to migrate from their dying universe to ours?

This would be one way to resolve the inherent paradox in the Participatory Anthropic Principle. Super-intelligent, godlilke beings in the LAST universe created THIS one with just the right values for Sigma and Lambda and the rest to allow for the rise of intelligence. [Think of the kicker in Sagan's novel Contact, at the very end, where we discover that the number pi, in Base-11 counting but expressed in binary, I think it was, draws a perfect circle inside the number some hundreds of billions of decimal places in as a kind of signature by the Creator.]

Without invoking inter-universal travel, we could also imagine an end-time ultracomputer traveling back in time to the instant of the Big Bang in order to impose the necessary order. Talk about tautologies!

Here's another. Suppose Tippler's end-point alien civilization was a kind of ultra-supercomputer, perhaps blending all of the evolved intelligence of an entire ancient universe together in a single instrumentality. Suppose that this cosmic computer, to dredge up that hoary old cliche of a pulp-SF phrase, could create simulations of life and reality... kind of like the experiments in virtual life we have going on in computer labs now, in fact. The denizens of such virtual worlds would have no way of experiencing the real universe Outside. Think of the movie Matrix, where what we think of as reality is computer code generated by a powerful AI set in the year 23-something, so that we don't know that we are organic batteries grown in robotic farms.

Indeed, the only clue to the true nature of our existence might lie in the statistical unlikeliness of the numbers that define the universe. We're stuck inside the universe, we can't see out or look in at ourselves from outside... but we can look at Lambda and Q and D and the others and say.... "Wait a second! Reality is... artificial! It was deliberately fine-tuned to allow us!"


Or consider this: if said hyper-intelligences created such a system, they might use it to run thousands... millions... billions of virtual simulations in order to probe and study the nature of existence and life through infinite possibilities. If that is the case... what is more likely statistically? That we are the very first evolved life to consider doing such a thing, but we're not yet technologically proficient enough to do it? Or that we are one of the near-infinite number of iterations that follow, residing within virtual realities?

Again, the only clue might be... is our universe essentially random? Or are there fine-tuned constraints that suggest... stage props? A Man Behind the Curtain?

Or think about this: if hyper-intelligent aliens fill their universe, then conspire to create a new universe to follow theirs--if, in fact, as the Final Anthropic Principle suggests, life must expand to totally dominate and control its universe... what's more statistically likely? That we are in the first such universe? Or that we're experiencing one of a near-infinite succession of created universes that follow the first? Again, the apparent fine-tuning suggests artificial manipulation, as well as the possibility that those universal numbers become progressively tighter and more precise with each iteration, a successive cosmological evolution.

Or this: Such speculation actually provides the very best resolution for the Fermi Paradox that I can imagine. The Fermi Paradox, of course, is the observation by Enrico Fermi that if life and intelligence are common, the first truly interstellar species would have appeared on the galactic stage something like four to eight billion years ago. Even if travel at faster than light speed is absolutely and forever impossible, such a species, if it was mature enough not to destroy itself, would be able to expand throughout the entire Galaxy, colonizing life-friendly worlds, rearranging lifeless matter into Dyson Spheres or even grander cosmic engineering projects in no more than 200 million years... and possibly in as brief a time as 10 million years. In other words, they should be here already, and so, as Fermi famously stated, where are they? Okay, maybe we're the first--someone has to have that honor--or maybe there is some built-in trap that destroys intelligent species before they can spread across the Galaxy, or maybe we won't find them until we can tune in on modulated neutrino beams or pick up on the Transcended Metaphysical Telepathic Channel on our hyperwave sets

But what if, as many SETI researchers are beginning to think, there's nobody else out there? That would be as profound a result for SETI as the discovery of intelligent aliens--perhaps more so. As it happens, I don't buy this one myself. I think the universe is teeming with both life and intelligence, and that we'll have proof of this within a few more decades. But the Great Silence must have a cause, and one valid possibility is that we're alone. This seems so freakishly unlikely that a reasonable explanation would be that this iteration of reality was created in order to study US. No aliens required. The sheer size and scope of the universe is there because life--on this one tiny dust-mote planet--requires it. [i.e. the universe had to be big enough to expand as it has for 13.7 billion years to allow galaxies to mature to an age permitting the seeding of heavy elements, so life could appear, so we could appear, and so on.]

Or consider this: if said intelligences are running an ongoing virtual simulation, how would they study it? Interact with it? Perhaps by downloading their minds or "souls" into lifeforms within the simulation?

Kind of like our Earthly concept of reincarnation; we download into bodies, experience life, then go back Home to examine and integrate what we've learned.... Hmmmmm.

Possible idea(s) for the next non-fiction book.


All text copyright (c) William H. Keith
This page was last updated on 08/12/2012

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