Why is the universe so big, and why is so much of it hostile to life?

Chris Kyle, Navy SEAL
Chris Kyle, Navy SEAL, can hit a very small target from a mile away – very improbable

Review: In case you need a refresher on the cosmological and fine-tuning arguments, as presented by a professor of particle physics at Stanford University, then click this link and watch the lecture.

If you already know about the standard arguments for theism from cosmology, then take a look at this post on Uncommon Descent.


In my previous post, I highlighted three common atheistic objections to to the cosmological fine-tuning argument. In that post, I made no attempt to answer these objections. My aim was simply to show that the objections were weak and inconclusive.

Let’s go back to the original three objections:

1. If the universe was designed to support life, then why does it have to be so BIG, and why is it nearly everywhere hostile to life? Why are there so many stars, and why are so few orbited by life-bearing planets? (Let’s call this the size problem.)

2. If the universe was designed to support life, then why does it have to be so OLD, and why was it devoid of life throughout most of its history? For instance, why did life on Earth only appear after 70% of the cosmos’s 13.7-billion-year history had already elapsed? And Why did human beings (genus Homo) only appear after 99.98% of the cosmos’s 13.7-billion-year history had already elapsed? (Let’s call this the age problem.)

3. If the universe was designed to support life, then why does Nature have to be so CRUEL? Why did so many animals have to die – and why did so many species of animals have to go extinct (99% is the commonly quoted figure), in order to generate the world as we see it today? What a waste! And what about predation, parasitism, and animals that engage in practices such as serial murder and infant cannibalism? (Let’s call this the death and suffering problem.)

In today’s post, I’m going to try to provide some positive answers to the first two questions: the size problem and the age problem.

Here’s an excerpt for the size argument:

(a) The main reason why the universe is as big as it currently is that in the first place, the universe had to contain sufficient matter to form galaxies and stars, without which life would not have appeared; and in the second place, the density of matter in the cosmos is incredibly fine-tuned, due to the fine-tuning of gravity. To appreciate this point, let’s go back to the earliest time in the history of the cosmos that we can meaningfully talk about: the Planck time, when the universe was 10^-43 seconds old. If the density of matter at the Planck time had differed from the critical density by as little as one part in 10^60, the universe would have either exploded so rapidly that galaxies wouldn’t have formed, or collapsed so quickly that life would never have appeared. In practical terms: if our universe, which contains 10^80 protons and neutrons, had even one more grain of sand in it – or one grain less – we wouldn’t be here.

If you mess with the size of the universe, you screw up the mass density fine-tuning. We need that to have a universe that expands at the right speed in order to form galaxies, stars and planets. You need planets to have a place to form life – a place with liquid water at the surface.

And an excerpt for the age argument:

(a) One reason why we need an old universe is that billions of years were required for Population I stars (such as our sun) to evolve. These stars are more likely to harbor planets such as our Earth, because they contain lots of “metals” (astronomer-speak for elements heavier than helium), produced by the supernovae of the previous generation of Population II stars. According to currently accepted models of Big Bang nucleosynthesis, this whole process was absolutely vital, because the Big Bang doesn’t make enough “metals”, including those necessary for life: carbon, nitrogen, oxygen, phosphorus and so on.

Basically, you need heavy elements to make stars that burn slow and steady, as well as to make PEOPLE! And heavy elements have to be built up slowly through several iterations of the stellar lifecycle, including the right kinds of stellar death: supernovae.

Read the rest! These arguments come up all the time in debates with village atheists like Christopher Hitchens and Richard Dawkins. It’s a smokescreen they put up, but you’ve got to be able to answer it using the scientific evidence we have today. They always want to dismiss God with their personal preferences about what God should or should not do. But the real issue is the design of the cosmological constants that allow life to anywhere. That’s the part that’s designed. And that’s not a matter of personal preference, it’s a matter of mathematics and experimental science.

One last parting shot. If God made the universe have life everywhere, the first thing atheists would say is “See? Life evolves fine by itself without any God!” The only way to recognize a marksman is when he hits a narrow target (not hostile to life) from a wide range of possibilities that have no value (hostile to life). We don’t credit Chris Kyle for hitting the wall above an Islamic terrorist from a mile away, we credit Chris Kyle for hitting an Islamic terrorist a mile away. The design is not how much of the universe is hospitable to life versus how much is hostile to life. The design is in the cosmological constants – where we are in the narrow band that is hospitable to life and not in the huge regions that are hostile to life.

You can read the best explanation of the design argument in this lecture featuring Robin Collins. That link goes to my post which has a summary of the lecture. He has a new lecture that I also blogged about where he extends the fine-tuning argument down to the level of particle physics. I have a summary of that one as well.

5 thoughts on “Why is the universe so big, and why is so much of it hostile to life?”

  1. Thank you for adding that marksman part near the end – that is something I had not considered – I added that to my “A Wasteful Universe?” apologetic. Very useful. One question:

    Does the solution you provided in (a) necessitate life evolving from non-life naturally, or does it merely show that in order for life to be sustained, a certain amount of time (and thus, space) had to pass? I guess that there is nothing that prevents God from specially creating at the point that the universe had evolved to in which life could be sustained, especially given the astronomical odds against life evolving from non-life?


    1. Life from non-life is ridiculous. What I am talking about is being able to make useful things like stars that burn a long time, steadily, and human bodies. That requires heavy elements, and they take a long time to make.

      Yes, God can do whatever he wants, but if he wants us to figure it out, then he uses mostly natural processes – except for the parts where he functions as a mind, sequencing the individual components like a software engineer would. But even software engineers use computers governed by natural laws to write their code.


      1. I agree 100%. Let me get a bit more specific. When you wrote:

        “What I am talking about is being able to make useful things like stars that burn a long time, steadily, and human bodies. That requires heavy elements, and they take a long time to make.”

        Then, the atheist is going to say “Oh, so you have the universe evolving through these long periods of time until you have an earth in a solar habitable zone, and a solar system in a galactic habitable zone, and then – what – God steps in and creates life? Or life evolves naturally from non-life just as the universe evolved naturally?”

        Please forgive me for being dense here, WK. You probably answered me, I am just wondering what the next event is. If we say “OK, God stepped in and created man and the different kinds,” then would not the atheist reply “But, He could have made everything in the universe in place without going through billions of years of universe evolution.” (I think some Christians do believe that God did precisely that and that the universe, thus, has the appearance of age. But, I know there are issues with that solution too.)

        Again, please be gentle in your reply: you are light years, pun intended, ahead of me in this area. I am NOT trying to devolve into an OEC versus YEC discussion either. Just trying to understand my next chess move with this important post you have made. That is my only motivation, not to drive you nuts, OK?


        1. Yeah God stepped in and put in the information for the first living cell, animal forms (Cambrian) and humans.

          There is no other candidate to put in the biological information than an intelligent agent. Naturalism cannot do that.


          1. Yes! That is what I was thinking! And to answer my own question on not making the universe in place, WLC made a good point about how God is not limited in resources (time, space, matter) like engineers would be. He can take His time and enjoy His creation in the same way that an artist does. He is both engineer and artist. (And a LOT of other things too, obviously.)

            One final question – please forgive me: is there any evidence that God had His hand directly involved in the shaping of the various habitable zones before life began, or did He merely set the initial conditions that would necessitate same – with near unbelievable accuracy and precision? Or is this an open question?

            Thanks, WK!


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