In addition to the parameters and constants necessary for life in the universe, there are also fascinating characteristics of a planet that are necessary for it to support complex life. Recent discoveries demonstrate that there are at least two dozen such characteristics that must be in place for life to be possible on a planet. These include its consisting of the correct mass; being orbited by a large moon, having a magnetic field; manifesting an oxygen-rich atmosphere; orbiting a main-sequence, G2 dwarf star; and being in the correct location in the galactic habitable zone. Each of these factors has to occur in the right place at the right time with respect to the same planet in order for complex life to even be a possibility there. The probability of these factors converging is so infinitesimally small that many cosmologists and astrophysicists now admit that it's more reasonable to believe that a divine designer was involved than to assume it all happened by chance.

Of course, not everyone is happy with this conclusion. Some are working overtime to find alternative theories to explain these phenomena without divine intervention. In fact, there are a few serious objections that we should address. The first is that these highly unlikely events can be explained without God if a very large number of universes exist besides our own, each with its own parameters and constants. If there are a very large number of universes and they were all produced randomly, most of them would surely include parameters that are life prohibiting. But if the number of universes is large enough—maybe infinite—then some of them, by sheer chance, might have just the right parameters for life. Luckily for us, the argument goes, our universe happens to be one that has the right parameters. 

One big problem with this objection is that there is no scientific evidence that it is true or even possible. It's purely speculative. Science fiction writers are having a heyday with the idea, but the scientific facts are lacking, to say the least. 

Another problem is that if there are an infinite number of universes, then those must have been produced by some kind of a "many-universe generator." But this generator itself must be a very sophisticated device in order to produce countless universes. I mean, even my toaster needs to be well designed to toast bread (though I'm not so sure it was really well designed, since it often pops my toast onto the kitchen floor!). How much more so a universe maker who produces countless universes, including finely tuned ones like our own. What kind of an incredible intelligence could account for such an astounding machine or process such as that? 

Yet another objection I often hear is this: if the evidence points to a divine designer, then who designed the designer? If we don't need to answer that question, it's argued, then why do we need to worry about a designer of our universe? While this is an interesting challenge, it misses the simple point that the universe is better explained by design than by chance. 

Consider this example: suppose you went on a deep-sea expedition and came upon what seemed to be an under­water city. It was unique, like nothing you'd ever seen before. Suppose there were structures apparently designed to sustain oxygen-breathing creatures (like us), including rooms from which water could be evacuated, long tubelike tunnels that could pump in oxygen from above the water, and various inlets that could be used for transportation purposes. 

In this scenario, it would seem far more reasonable to believe that there was a designer who created this place than to suppose that it came into being purely by chance. But we would not need to forgo the claim that an intelligent being designed the city just because that intelligent being itself may be in need of further explanation. So the question of whether or not God needs further explanation, though an interesting one, has no bearing on this argument about our finely tuned universe.