Friday, May 11, 2012

Read Along: Chapter 7—Why is the Universe Just Right for Life?

Today we continue with Chapter Seven in the Read Along with Apologetics 315 project. This is a chapter-by-chapter study through the book Is God Just a Human Invention? And Seventeen Other Questions Raised by the New Atheists by Sean McDowell and Jonathan Morrow. (Hear an interview about the book here.) Below you will find an audio intro for Chapter Seven, a brief summary of the chapter, a PDF workbook with questions for the chapter, and some notable quotes. You’re also encouraged to share your comments and feedback for each chapter in the comment section below. Feel free to interact!

[Audio Intro] – Sean McDowell introduces this chapter.
[Chapter 07 Study Questions] (with kindle locations) – PDF study guide.
[Podcast Feed RSS | Podcast in iTunes] – Click to subscribe to the audio.

Chapter Seven: Why is the Universe Just Right for Life?
(pages 95-107)

Chapter seven looks at the fine-tuning of the universe for life. From the expansion rate of the universe, to the tuning of the four fundamental forces, to the fine-tuning of the constants, the authors summarize some of the main reasons physicists acknowledge that the universe is delicately balanced for life. They also point out the atheistic objections to pointing to a fine-tuner, such as the weak anthropic principle, “who designed the designer?”, and the multiverse hypothesis.

Jay Richards contributes an essay responding to the objection that the fine-tuning argument doesn’t “go far enough” to point all the way to the Christian God. However, Richards argues that the argument goes just as far as it is supposed to.

Notable quotes:

What happens when we try to assign a probability to the fine-tuning of all the known constants of nature? Oxford physicist Roger Penrose concluded that such a task would be impossible, since the necessary digits would be greater than the number of elementary particles in the universe.6 This level of precision completely dwarfs human technology and innovation. (p. 97)

Given all the possible variations of the constants, why do we happen to find ourselves in a universe capable of supporting life? Merely claiming that we could not observe ourselves in any other universe offers no explanation for why we are actually in a fine-tuned universe in the first place. (p. 98)

Does this mean that multiple universes, if they were ever discovered, would undermine God? Absolutely not! We would still be left with the question as to what generated our fine-tuned universe, and any system that generates a habitable universe must itself be fine-tuned. The multiverse hypothesis simply moves the fine-tuning problem up one level, asking why multiple universes are able to sustain life. (p. 100)


  1. How would you respond to the “who designed the designer” objection?
  2. How would you respond to the weak anthropic principle objection?
  3. Why does the multiverse hypothesis not defeat the design hypothesis to account for fine-tuning?
Recommended Reading
Next Week: Chapter 8—Has Science Shown There is No Soul?


  1. Gavin May 12, 2012

    "1. If the balance between gravity and expansion rate were altered by on part in one million billion billion billion billion billion billion there would be no galaxies, starts, planets or life. To put another way, if there was one more grain of salt the universe would not have expanded and one less and it would have expanded too quickly."

    This is not true. I'm not saying there are different opinions about this or that some models of the universe don't give this result. There is no question how this calculation should be done. All of the numbers required to do the calculation are well known. This calculation has been done in many places and scientists all agree on the result. I personally know how to do the calculation and can check it. The "one grain of salt" result in wrong. In fact, it is ridiculous.

    Have you felt the gravitational pull of one grain of salt? No, it's too small. Yet here the authors are claiming that this pull is enough to collapse the universe. An extra grain of salt is not enough. An extra galaxy is not enough. An extra billion galaxies is not enough. An extra billion, billion galaxies is probably enough.

    Here is my question. How is it that the authors look at all of the evidence that evolution, through random variation and natural selection, is responsible for the complex information life and conclude that it is just too improbable to be believed, then turn around in the very next chapter and claim, without a hint of reservation, that a single grain of salt would crush the universe?

    This isn't an isolated incident. They frequently show great skepticism towards well established scientific knowledge then assert with great confidence claims with little or no supporting evidence. In some instances I can understand a little confusion, but this grain of salt mistake shows a complete lack of seriousness.

  2. Brian Auten May 12, 2012


    May I ask if you are reading the book, or just the extracted quotes? I just want to see where you are coming from here, as this quote is talking about the initial conditions of the universe at the point of singularity, and it sounds to me as if you are talking about the universe as it is now.

    The fine-tuning of the universe is really not in dispute by anyone. It's the question of what accounts for the fine-tuning that is in dispute.

  3. Gavin May 12, 2012

    I have the book in front of me, and I have to apologize for putting a paraphrase in quotes. Here is the exact quote.

    "If the initial mass of the universe differed by as little as one grain of salt, there would be no universe. Add one grain of salt and the universe would not have expanded; take one grain away and the universe would have expanded too quickly to form galaxies, solar systems, and habitable planets."

    You are correct that there are real fine-tuning issues. However, this quote does not touch on any of them. This is what I find so frustrating. They say "Let's look at a couple examples of this exquisite fine-tuning," then two of the three examples (this one and planets) are not actually examples of fine tuning. Maybe it doesn't matter to them as long as they make their point, but it does show, as I said, a complete lack of seriousness.

  4. Gavin May 12, 2012

    I intended stay positive, and I haven't done that. Readers at this blog have shown an admirable interest in learning about the universe. I should have focused on satisfying that curiosity rather than unleashing my frustration with the book's authors. Let me try to write something helpful, since many of you seem eager to learn.

    I can go trough the three "examples of this exquisite fine-tuning" and tell you the natural explanation for each. We have greater confidence in some of the explanations than others. I will start with the area where we are most confident first. If anyone is interested, I will continue.

    The Earth is indeed a very nice planet for life, there are certainly many such planets.

    Using observatories like the Hubble Space Telescope, we have learned a great deal about the stars and galaxies in our universe. The part of the universe that we can see contains about 100 trillion galaxies. Spiral galaxies are common, but not the most common. There are probably trillions of spiral galaxies. Each of those contains hundreds of billions of stars. Most of those stars are in the habitable part of the galaxy. Stars that can support life are common, but not the most common. Each spiral galaxy probably contains billions of stars that can support life. That means that there are at least a billion trillion stars in the observable universe that can support life.

    In addition to the right kind of star, life also needs the right kind of planet. Over the last few years the Kepler mission has shown that planets are very common. Kepler is a space telescope that continuously watches 500,000 stars for evidence of planets. Thousand of planets have been seen. Kepler can only see planets that come directly between us and their star, so the number seen tells us that most stars have many planets, just like the Sun. Many of these planets are the right distance from their star (in the habitable zone). Many of these systems have large planets that can clean up dangerous comets and asteroids. Many of these systems have Earth size planets, although these are difficult to see. We have seen Earth size planets in the habitable zones of some of these stars. Solar systems like ours do not seem to be especially rare. In our observable universe there are probably a billion billion planets that are the right size, in the right orbit, in the right sort of solar system to support life.

    The only remaining issue is the Moon. We have a very difficult time seeing moons around planets orbiting other stars, so it is impossible at this time to say how common they are. We know that our Moon formed from the debris ejected when Earth was hit by a Mars size planet billions of years ago. This sort of event is probably common, since the formation of solar systems involves a lot of collisions. How often that forms a moon is something I don't know. Many of the planets in our solar system have moons, but most of them are not big enough to stabilize the planet's spin axis. Based on what we know, the presence of a nice moon is probably rare, but not incredibly rare. That still means billions of habitable planets in the observable universe, just as a result of natural galaxy and planet formation.