Anthropic Principle

"A life-giving factor lies at the centre of the whole machinery and design of the world." John Wheeler

"everything about the universe tends toward humans, toward making life possible and sustaining it" Hugh Ross

"... the Anthropic Principle says that the seemingly arbitrary and unrelated constants in physics have one strange thing in common--these are precisely the values you need if you want to have a universe capable of producing life." Patrick Glynn

The Anthropic Principle was first suggested in a 1973 paper, by the astrophysicist and cosmologist Brandon Carter from Cambridge University, at a conference held in Poland to celebrate the 500th birthday of the father of modern astronomy, Nicolaus Copernicus. The Anthropic Principle is an attempt to explain the observed fact that the fundamental constants of physics and chemistry are just right or fine-tuned to allow the universe and life at we know it to exist. (see Cosmic Matters). The Anthropic Principle says that the seemingly arbitrary and unrelated constants in physics have one strange thing in common--these are precisely the values you need if you want to have a universe capable of producing life. The universe gives the appearance that it was designed to support life on earth, another example of Paley's watch.

• Gravity is roughly 1039 times weaker than electromagnetism. If gravity had been 1033 times weaker than electromagnetism, "stars would be a billion times less massive and would burn a million times faster."
  
• The nuclear weak force is 1028 times the strength of gravity. Had the weak force been slightly weaker, all the hydrogen in the universe would have been turned to helium (making water impossible, for example).
  
• A stronger nuclear strong force (by as little as 2 percent) would have prevented the formation of protons--yielding a universe without atoms. Decreasing it by 5 percent would have given us a universe without stars.
  
• If the difference in mass between a proton and a neutron were not exactly as it is--roughly twice the mass of an electron--then all neutrons would have become protons or vice versa. Say good-bye to chemistry as we know it--and to life.
  
• The very nature of water--so vital to life--is something of a mystery (a point noticed by one of the forerunners of anthropic reasoning in the nineteenth century, Harvard biologist Lawrence Henderson). Unique amongst the molecules, water is lighter in its solid than liquid form: Ice floats. If it did not, the oceans would freeze from the bottom up and earth would now be covered with solid ice. This property in turn is traceable to the unique properties of the hydrogen atom.
  
• The synthesis of carbon--the vital core of all organic molecules--on a significant scale involves what scientists view as an astonishing coincidence in the ratio of the strong force to electromagnetism. This ratio makes it possible for carbon-12 to reach an excited state of exactly 7.65 MeV at the temperature typical of the centre of stars, which creates a resonance involving helium-4, beryllium-8, and carbon-12--allowing the necessary binding to take place during a tiny window of opportunity 10-17 seconds long. Taken from God the Evidence by Patrick Glynn
  

The fact that we are living and can observe the universe, implies that the fundamental constants must be "just right" to produce life. There is an element of circular reasoning here, because if the constants were not "just right", we would not be here to observe the universe. However, the fact is that the universe does not seem to be a random or chance event. We can postulate a many universe scenario, in which only one or some universes produce life, but we cannot validate that scientifically because we only live in one of those universes.

Here are some definitions, first from Barrow and Tipler:

Weak Anthropic Principle (WAP): The observed values of all physical and cosmological quantities are not equally probable but they take on values restricted by the requirement that there exist sites where carbon-based life can evolve and by the requirements that the Universe be old enough for it to have already done so.

Strong Anthropic Principle (SAP): The Universe must have those properties which allow life to develop within it at some stage in its history. Because:

1. There exists one possible Universe 'designed' with the goal of generating and sustaining 'observers'. Or...
   
2. Observers are necessary to bring the Universe into being (Wheeler's Participatory Anthropic Principle (PAP)). Or...
   
3. An ensemble of other different universes is necessary for the existence of our Universe (which may be related to the Many_Worlds interpretation of quantum mechanics).
   

Final Anthropic Principle (FAP): Intelligent information-processing must come into existence in the Universe, and, once it comes into existence, it will never die out.

The above is taken from Anthropic Principle

Copernicus suggested the sun-centred model of the planetary system rather than an earth-centred model. 500 years later the Anthropic Principle puts mankind back to centre-stage. The Anthropic Principle refutes the Darwinist's claim that we are the product of mere chance. The universe is not so random as we thought. We have a universe with a beginning and designed for man.

Books:
The Anthropic Cosmological Principle by John D. Barrow, Frank J. Tipler (Contributor) - 706 p.
Rare Earth : Why Complex Life Is Uncommon in the Universe by Peter Douglas Ward, Donald Brownlee (shows what makes planet earth suitable for life - habitable zones of the universe, factors include the Moon, Jupiter, continental drift).
The Privileged Planet: How Our Place in the Cosmos Is Designed for Discovery by Guillermo Gonzalez, Jay Wesley Richards
The Case for a Creator: A Journalist Investigates Scientific Evidence That Points Toward God by Lee Strobel
The Origin of the Universe (Science Masters Series) by John D. Barrow
The Physics of Immortality : Modern Cosmology, God and the Resurrection of the Dead by Frank J. Tipler
The Creator and the Cosmos : How the Greatest Scientific Discoveries of the Century Reveal God by Hugh, Ph.D. Ross. 185 p.
Beyond the Cosmos: What Recent Discoveries in Astrophysics Reveal About the Glory and Love of God by Hugh Ross
A Brief History of Time by Stephen Hawking
Stephen Hawking's Universe : The Cosmos Explained by David Filkin, Stephen Hawking
God : The Evidence : The Reconciliation of Faith and Reason in a Post-Secular World by Patrick Glynn (Ch 1 deals with the evidence from the big-bang and the anthropic principle)
Links
Design and the Anthropic Principle by Hugh Ross
The Designed 'Just So' Universe Walter L. Bradley, Ph.D.
The Completely Radical Anthropic Principle - Richard Harter's World
Does the Anthropic Principle indicate that God exists? - Krishna
Quantum Mechanics, a Modern Goliath by Hugh Ross, Ph. D.
Tipler's Physics of Immortality Rant / Review by John Walker October 26, 1994
Astronomical Evidences for the God of the Bible by Hugh Ross, Ph.D.
The Anthropic Principle: Yet Another Version?
Anthropic Principle, see also Cosmic Matters
anthropic-principle.com - good links
Barrow and Tipler on the Anthropic Principle vs. Divine Design William Lane Craig
Design In Nature: The Anthropic Principle by Donald B. DeYoung, Ph.D.*
Anthropic Principle We may occupy a preferred place or preferred time in the Universe (we may also occupy a preferred universe)
An Incredible Balancing Act, God, the Anthropic Principle and Inflation
An impertinent resumé of the Anthropic Cosmological Principle by Daniel Berger
Other related links:
The Structure and Evolution of the Universe - NASA
Albert Einstein Online
Astronomy 201/211 Winter Lectures - 33 lectures on astrophysics and cosmology - must visit