Without evolution it would not be easy to understand features of living creatures that seem poorly designed or serve no functional purpose. We see snakes with tiny legs buried inside their skins and flightless beetleswith wings. We humans possess an unnecessary appendix. How to explain these vestigial organs? Evolution says it is because snakes, flightless beetles, and humans are all descended from creatures that needed those organs to survive.

Still, evolution remains a theory with clear limits. When Dawkins subtitles one of his books “How the Evidence of Evolution Reveals a Universe Without Design” he shows no awareness of these limits. When Dennett invokes evolution as an all-purpose explanation in cosmology psychology culture, ethics, politics, and religion, he too goes way beyond the evidence.

Here we must distinguish between the empirical and metaphysical aspects of evolution. Dawkins and Dennett are metaphysical Darwinists. Biologist Stephen Jay Gould once termed them “Darwinian fundamentalists.” He faulted them, as I do, for using a powerful but quite circumscribed theory to account for phenomena that fall entirely outside its biological reach. Consider three massive features of life that evolution cannot account for.

Evolution cannot explain the beginning of life. Darwin didn’t even try. He assumed the first living thing, and then he tried to show how one living thing could be transformed into another. In 1953 there was considerable excitement when Stanley Miller generated amino acids by sending an electrical discharge through a combination of water, hydrogen, methane, and ammonia. This excitement subsided when it was subsequently established that the atmosphere of the early earth was mostly made up of carbon dioxide and ammonia.

So Miller’s experiment was not relevant to showing how life could have arisen out of non-life through random chemical interactions. Moreover, life involves a lot more than the generation of amino acids. The biggest problem is taking simple chemicals like amino acids and generating proteins and other essential components of life. The origin of life, biologist Franklin Harold confesses, is one of the “unsolved mysteries in science.”

The simplest living cell is one of the most complicated structures on earth, containing within it more information than multiple sets of the Encyclopedia Britannica. “The genetic code.” writes Richard Dawkins, “is truly digital, in exactly the same sense as computer codes.” As Dawkins shows, each DNA molecule is an algorithm in biochemical code with a built-in capacity for transcription and replication.

Harold remarks that even a bacterial cell “displays levels of regularity and complexity that exceed by orders of magnitude” anything found in the nonliving world. Besides, “A cell constitutes a unitary whole, a unit of life, in another deeper sense: like the legs and leaves of higher organisms, its molecular constituents have functions…. Molecules are parts of an integrated system, and in that capacity can be said to serve the activities of the cell as a whole.”

The cell, in other words, shows the marked signature of design. It is crucially important to recognize that this basic template of life, with all its intricate machinery of RNA and DNA, came fully formed with the first appearance of life. Evolution presupposes cells that have these built-in capacities. And scientists have found that the first traces of life go back between 3.5 and 4 billion years, only a short time after the earth itself was formed.