What is the Anthropic Principle?

Michael Anissimov
Michael Anissimov

The Anthropic Principle is the simple fact that we live in a universe set up to allow our existence. If the universe were any other way, we would not exist, and would hence be unable to make any observations. Since it was introduced by the theoretical physicist Brandon Carter in 1973, the Anthropic Principle has progressively come into vogue among the physics and philosophical communities, providing a simple explanation for some otherwise very perplexing coincidences. For example, why are certain physical constants so oddly fine-tuned? While some people view this as evidence for a supernatural creator, materialists simply observe that if it were any other way, we wouldn't be here.

The Anthropic Principle states that the universe had to be the way it is for people to exist.
The Anthropic Principle states that the universe had to be the way it is for people to exist.

Due to the Many Worlds Interpretation of quantum mechanics, many physicists have come to view our universe as one among many--possibly an infinite number, or superset of universes sometimes called "the multiverse." Though we know nothing about the underlying process which could generate such universes, presumably it is random, leading to universes with a variety of different sizes, ages, densities, dimensions, and fundamental physical laws.

Considering a multitude of randomly generated universes, it seems as if many would be hostile to the existence of the delicate, self-perpetuating arrangements of matter known as life. Even a smaller subset would include intelligent observers. If consciousness is only exhibited by a subset of intelligent minds, then there may even exist universes populated by unconscious intelligences, or the hypothetical entities known in philosophy of mind as "zombies." These fascinating lines of thought all follow from the recognition of the far-reaching consequences of the Anthropic Principle.

Anthropic reasoning has been employed in areas ranging from superstring theory--the effort to create a unifying theory of quantum gravity--to predicting the future of the human race; to guessing at the fate of the universe. Use of the Anthropic Principle has been criticized for its almost-eerie ability to contribute to inductive processes in a variety of domains. Also, because it is so new and unusual, critics claim this pricincple has been overextended in certain areas. For example, in The Anthropic Cosmological Principle, John Barrow and Frank Tipler introduce a "Final Anthropic Principle," which states that once intelligent life comes into existence in the universe, it will never die out. Such gung-ho extensions of the Principle have rallied skepticism among certain thinkers. Others feel it is simply too broad to make useful, testable, specific predictions.

Michael Anissimov
Michael Anissimov

Michael is a longtime wiseGEEK contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

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Discussion Comments


I see only two possible answers to the anthropic principle: Intelligent agency as a cause or infinite universes. While I am open-minded to multiverse theories, they present serious problems, give us no evidence of their existence and they don't answer everything anyway.

Some things are still impossible, even with infinite attempts. The example of "unconscious intelligence" is oxymoronically impossible, no matter how many universes there are. The answer to achieving consciousness is not "just add more universes".

What we know from quantum mechanics about the role of conscious awareness in giving attributes to matter tells us that conscious intelligence not only *did* cause the universe at the Big Bang, but that what we perceive as reality is still constantly being formed by intelligence.

I have to agree with Post no. 5. Intelligent agency causes the universe. The more we learn, the more certain that becomes.


The only possible cause of reality is an information process. Things are defined by how they relate to other things. The Multiverse is infinite possibilities without cause. Everything has a cause and love is the only eternal one.

The universe was created so beings could relate to each other, discover love and join the host of beings serving the eternal cause, which is love.

To those who have wisdom, the Anthropic Principle reveals the hand of God behind nature. All one needs to do to prove it is design a reality capable of creating conscious life with free will.

To believe something as complex as reality could have come about by chance and have no cause, reveals a blindness beyond logic is operating in the world. What exactly was the forbidden fruit? Did it open eyes or close them?


@JessicaLynn - Theories and principles can often be headache inducing. I think that is because sometimes people try to make theories and ideas overly complicated. The anthropic principle is basically just saying the universe exists and consequently so do we. Very obvious.

I think the madness begins when people start asking "what if" and talking in circles.


This anthropic principle definition is very interesting. The theory works on an astronomical level as well as a cellular level. The processes and reactions in the human body and just as specific and fine tuned as the laws of the universe.

For example there have to be many specific chemical conditions for processes such as respiration and circulation to occur in the human body. Respiration and circulation are essential to life so in being organized the way it is the body is set up to allow for life.

These kind of theories normally give me a headache but this one actually makes sense to me.


@anon137166 - I guess it is! But on a bigger scale. One person wouldn't be able to have thought if s/he didn't exist, and people wouldn't be able to measure the universe if it wasn't appropriate for us.

I wonder how much of our understanding is limited by us being what we are. Maybe other universes are so different that they would be hostile to any sort of life that we could conceive of or understand--doesn't mean that they couldn't have some kind of life. Or maybe I just watch too much Star Trek!


the anthropic principle is very similar to descartes' "I think. Therefore i am."

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