A “Fine-Tuned” Universe as Proof of a God?

There are many scientists who believe that, if one or more physics constants of the universe had varied only slightly, they would have produced a universe incapable of supporting life. For example, if one constant had been slightly different, the universe would have collapsed back in upon itself before life had a chance to form.

Some religious people look at this supposedly “fine-tuned” universe and claim it is proof that a god exists who did the fine-tuning. Let us examine this claim.

God of the Gaps

At heart, this is a god-of-the-gaps argument. It says that since we can’t think of a natural way that the odds would have resulted in life in the universe, that “god did it.” However, we have no knowledge of what this god is, nor what mechanism it uses to accomplish anything. Therefore, “god” is not an answer to anything.

Religious people claim that we aren’t entitled to a “free lunch” when it comes to assuming a natural explanation for life in the universe, but “god” is the ultimate free lunch–no explanations are ever provided.

The Universe

The vast, vast majority of the universe is decidedly inhospitable to life. Outer space is deadly to anything other than, perhaps, microbes–and the majority of planets, moons, and asteroids aren’t much better.

Judging by what we observe now, the universe will continue expanding forever, creating a “big chill” effect. Heat energy will be so dissipated that no life will be possible. A person alive just before this happens won’t view things as so “miraculously fine-tuned” as some religious people do today.

Our Sun

While natural conditions are favorable for life on Earth now, this won’t be true in about five billion years. At that point the sun’s supply of hydrogen will run out and it will begin to fuse helium into heavier elements. The sun will expand and engulf the Earth, wiping out all life. Even a billion years from now, all water will have boiled off the Earth, making life improbable, if not impossible. Again, a person alive just before either of these events occurs won’t view things as so “miraculously fine-tuned” as some religious people do today.

The Earth

Apart from the physics constants of the universe, some religious people claim that the Earth itself is so fine-tuned for life (proper distance from the sun, the right kind of elements, etc.) that only a god could have established it. This, of course, is the same god-of-the-gaps type argument we encountered with the “fine-tuned” universe.

An obvious natural explanation is that, given the likelihood of trillions of planets existing in the universe, it would only take a tiny fraction of them to have the right kind of conditions to produce some type of life. If only one planet per galaxy had life on it, that would still amount to 100 billion planets and at least 100 billion different species.

Limited Knowledge

The fined-tuned universe argument for a god assumes that what we think we know about the universe today is accurate. But this is cutting edge physics, and what we believe to be true today is far from certain. Even now there is much dispute among physicists as to how much these constants of the universe can vary and still produce a universe capable of leading to life.

Multiple Universes

Extraordinary odds against life in one universe become a near certainty if there are many universes. If many universes exist (sometimes called a “multiverse”), or many “bubble universes” exist within a single universe, and each universe or bubble universe has its own set of random constants, then life will almost certainly arise in at least one of these universes or bubble universes. (For example, roll a set of dice long enough and you will eventually get two sixes.)

While there is, as yet, no evidence for other universes, their existence is more plausible than the existence of a god. After all, we know it’s possible for universes to exist–we live in one. We have no evidence that it is possible for gods to exist.

A Fine-Tuned God?

Those who believe a “fine-tuned” universe proves the existence of a god admit there is some slight margin for variance in these physics constants of the universe. But what about the god they believe exists? Could that god be anything other than exactly what it is? If not, then there is zero margin for variance for that god. So, as improbable as the existence of life in the universe may seem, the existence of a god would be even more improbable.


The track record of naturalistic science for answering questions about the natural world far exceeds the track record of supernatural “revelation.” The existence of a god seems more improbable than life arising in the universe. “God” has not provided us with any answers and has instead raised more questions.

August Berkshire is president of Minnesota Atheists.

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7 Responses to “A “Fine-Tuned” Universe as Proof of a God?”

  1. June 14th, 2010 at 9:20 am

    Uncle Bob says:

    Could add some other problems to the list. It begs the question of what an “undesigned” universe would look like? What does it compare to?

    Also assumes that the “God” desires life in the first place. Maybe He desired black holes and life was an irrelevant byproduct.

    Just a couple off the top of my head. Good article.

  2. June 14th, 2010 at 10:15 am

    Reginald Selkirk says:
  3. June 14th, 2010 at 10:18 am

    The Phytophactor says:

    If you think this a finely-tuned universe for life, then you must accept that this universe,or other universes, could be less well tuned, and indeed, hostile to life. Either way, that we exist in a hospitable, at least for a time, universe, where else would we be if the result of a natural process? So to think this in some way argues for a god/tuner is to not understand the argument at all. If the cosmic dice come up hospitable, good for life, and the possibility that an intelligence species can begin to comprehend it all, and if not a lucky roll, then who would know? Never thought the anthropic principle was a very strong argument.

  4. June 14th, 2010 at 11:11 am

    The Science Pundit says:

    Proponents of the “fine tuning” argument invariably suffer from the misconception that the laws of nature are prescriptive rather than descriptive. The whole argument rests on the notion that subatomic particles and moving objects and gravitational and electromagnetic fiels, etc. are al following some sort of “rule book”, and that a “Grand Tinkerer” can therefore adjust some dials and make the universe a different place.

    But the laws of nature are NOT prescriptive! They are our descriptions of how we observe nature to work; and they are (to varying degrees) rough estimates at that. It’s not that the universe would be a very different place if the physical constants were slightly different, it’s that a very different universe would have different constants (assuming the required measurements could even be made in such a universe).

    I know it sounds like I’m splitting hairs, but I see the whole “fine tuning” argument as gibberish in a world where the laws of nature are descriptive. The argument seems just as silly as if I were to say that “the universe would be a vastly different place if the ratio of a circle’s circumference to its diameter were just slightly different than π” or that “the universe would be a vastly different place if 2+2 were slightly different than 4”. It sound like a fun premise for a science fiction story, but a cogent argument for the existence of gØd? Hardly.

  5. June 14th, 2010 at 3:46 pm

    abb3w says:

    Fine tuning also presumes “life anything like we understand it”.

  6. June 14th, 2010 at 3:56 pm

    Ken says:

    Ah yes. The “If things were different, they wouldn’t be the same” argument. I’ve heard it far too often.

  7. November 17th, 2010 at 7:10 pm

    Bil says:

    Has anyone heard of David Hume? This is simply the argument from design, with all of its problems. As for the ‘odds’ of life, it is irrelevant. What are the odds of my existence? Of my parents meeting to make me? Of a particular sperm and egg meeting to make my mom? My grandma? My great-grandma? I hope you get the picture – something has to happen, and we happen to live where life is possible. Fine tuning literally means nothing. Oh, and should I even mention that we still would need to explain how the designer was designed?

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