The Anthropic Cosmological Principle

Aryzel

Many of the fundemental forces of nature seem extremely well tuned to specific values to allow the existance of humans. If these values were even slightly different we wouldn't exist.

The Anthropic Principles, (there a two versions),
basically try to explain this coincidence.

The Weak Principle:
If the values were different we wouldn't be here to notice, so the values have to be like this.

The Strong Principle:
There are many possible universes and we are in the one that suits us.

Problems with Weak Principle:
Its a hell of a coincidence, the weak principle is basically like winning the lotto every week of your life. Nice but a bit suspicious, but no impossible.

Problems with Strong Principle:
Those extra universe are mighty hard to find, if you could prove infinite universes exist then, its probably correct.


Every time i see the Anthropic Principles discussed its always those two arguments, and dispite the fact that you can't add anything beyond what's above the arguments tend to go on for ages.

But what i always thought, but i don't remember seeing anywhere is, i suppose the 'Anthropic (Intelligent Life is Easy) Principle' :P

Anthropic - Intelligent Life is Easy - Principle
Regardless of the basic forces, ect. of the universe you'll probably get Intelligent life eventually.
All you need for intelligent life is information storage, communication and feedback.

Problem with Anthropic - Intelligent Life is Easy - Principle
Don't know what are the requirements for intelligent life,
Information storage, communication and feedback, seem about right, but.....
Also don't know if Intelligent life is emergent. What concentration of the requirements and what time scales are needed for the intelligence to emerge.
Don't know if most universe setups would provide these requirements, although this could be shown i suppose, mathematicaly create other universes and see how many of them can provide the requirements.


The Easy Life principle is similar to the Strong principle.
You'd be swapping infinite universes (still possible though) for infinite ways of creating intelligent life.

The Easy Life principle would probably be more open to proof than the multiple universe one, which seem impossilbe to prove. And the Weak principle is a bit dodgy, as much as i'd be happy winning the lotto every week, i'd start to wonder after a while. :P

Stark

Research is showing the infinite universes possiblity to be quite likely. They're even showing how pocket universes with their own laws of physics are popping up all the time within our own universe.

Our universe is quite likely a pocket universe within another universe that just happened to have the right conditions to survive (enough explosive force for a big bang, not collapsing on itself and not expanding too far).

albertw

Originally posted by Aryzel
Many of the fundemental forces of nature seem extremely well tuned to specific values to allow the existance of humans. If these values were even slightly different we wouldn't exist.

Many of the forces of nature may appear well tuned on Earth to allow the existance of humans. But forces are forces and not tuned to anything.

For exmaple gravity is not tuned for anything, gravity is a force dependent on the mass of the planet and the distance you are to it. It suits us on earth as the planet happens to be the right size.
The planet hapens to be close enough to the sun to be warm (ish!) and to have a molten core to generate a magnetic filed. But electromagnetism isn't tuned for humans.

The same forces of nature act here as they do everywhere else. It just happens that the Earth is well paced and the right size, and of the right composition to suit us.

Cheers,
~Al

Aryzel

k.oriordan:
Yes, using theories multiple universes appear to exist, but i haven't heard of any ideas to prove they exist in reality. What physical proof can be shown? It can be shown to be possible but proof is a another story.

albertw:
You're right the Earth is in exactly the right place for life. But thats not a problem, there are tons of planets in the universe, the fact Earth is right for us, is just a matter of probability.

The Anthropic Principle is the same thing, just applied to the universe. I should have made it a bit clearer what i ment by the tuning of forces.

The force of gravity is as you said dependent on distance and mass. as you double your distance the gravity drops to a quater. But it doesn't have to, gravity could be so strong that planets collapse into black holes, or so weak that stars could never form.

There are 4 fundemental forces, Gravity, Electromagnetism, Strong Nuclear Force, Weak Nuclear Force. And they all interact in various ways. There is also the expansion of the universe, the virtual partical force, cant think of its name, where particals pop in and out of existance ect.

Their strengths and interactions all have specific values, similar to the way the earth is the right distance from the sun to have water.

But there is no requirement for those forces to have the specific values we see, with slightly different Strong and Weak nuclear forces the very atoms that make up the matter in the universe would not have formed.

That reminds me, other possibility, the values of the universe might be built in, it appears Gravity and the rest can have any values, but they might not, it is possible the forces values naturally are what we see. But then your back to the Weak Principle, how likely is it that the natural values suit us....

rde

If you're looking for proof of multiple universes, you can approach it from two directions; the quantum mechanical approach (which I can't really speak authoritatively on), and the inflation approach (which I can't either, but know a bit more about).

There's little doubt now that the big bang happened, and there's relatively little doubt (but it's not certain) that inflation was a major component of the really early universe. This theory has it that there are many, many, many universes (possibly not infinite), and that each one can have its own set of parameters with regard to the speed of light, the mass of the electron, etc, etc. Obviously, most of those universes can't support life (or atoms, for that matter). We know of one that can, and because it can we're around to as questions.

John Gribbin explained it a lot better than I ever could; check out http://www.biols.susx.ac.uk/home/John_Gribbin/cosmo.htm

Gleanndún

did ne1 ever think---a basic law of biology really---that our universe inst suited to us, that rather we are suited to our universe?

joshcork

Well the principle is more of... if this isn't so we would be here to notice it, not that the universe is built around us or we adapted to it were just luck and observant.
On reading a couple of books on various astro physics related topics an example of this anthropic principle is beryllium, which i think when it was being created during the big bang was a critical element necessary to build on for heavier elements. I'm not sure but someone like roger penrose predicted something like that before and experimental data was aquired I'll look it up and get it right.
Anyway this beryllium element decays very fast under normal circumstances and it was only luck i suppose that a couple of electron volts allowed it to survive long enough to be built on and elements such as carbon got created.