Polkinghorne discusses the origins and aims of natural theology in this series. It does not offer truth, but rather a “best explanation” for the world, answering primarily meta-questions. Two such questions asked by Polkinghorne are, “Why is science possible at all?” and “What makes the universe so special?” To explore the answers, he looks at the ability of human minds to penetrate mysteries of the natural world as well as the fine-tuning of the universe necessary to produce the fruitfulness of life.

Every field of science has unanswered questions and gaps in our understanding. Scientists typically view these as open research questions. Others sometimes argue that if science can’t explain how something happened, then God must be the explanation. Such arguments are called “god-of-the-gaps” arguments. The risk in these arguments is that science is always developing. If gaps in scientific knowledge are the basis for belief in God, then as scientists fill in the gaps, the evidence for God disappears. The God of the Bible, however, is much more than a god of the gaps. Christians believe that God is always at work in the natural world, in the gaps as well as in the areas that science can explain.

I ask the question, “Why is the universe so special?” Now scientists don’t like things to be special; we like things to be general, and our natural anticipation would have been that the universe is just a common specimen of what a universe might be like.

Fine-tuning refers to the surprising precision of nature’s physical constants, and the beginning state of the Universe. To explain the present state of the universe, even the best scientific theories require that the physical constants of nature and the beginning state of the Universe have extremely precise values.