Editor’s note: This article is an excerpt from a chapter in the newly released book The Comprehensive Guide to Science and Faith: Exploring the Ultimate Questions About Life and the Cosmos. We are presenting Dr. Meyer’s chapter as a series, in which this is the second post. Find the full series so far here.
As I noted, Darwin attempted to explain the origin of new living forms starting from simpler preexisting forms of life. Nevertheless, his theory of evolution by natural selection did not attempt to explain the origin of life — the origin of the simplest living cell — in the first place. Yet there now is compelling evidence of intelligent design in the inner recesses of even the simplest living one-celled organisms. Moreover, a key feature of living cells — one that Darwin knew nothing about — has made the intelligent design of life scientifically detectable.
In 1953, when Watson and Crick elucidated the structure of the DNA molecule, they made a startling discovery. The structure of DNA allows it to store information in the form of a four-character digital code. Strings of precisely sequenced chemicals called nucleotide bases store and transmit the assembly instructions — the information — for building the crucial protein molecules and machines the cell needs to survive.
A Famous Hypothesis
Francis Crick later developed this idea with his famous “sequence hypothesis,” according to which the chemical constituents in DNA function like letters in a written language or symbols in a computer code. Just as letters of the English alphabet may convey a particular message depending on their arrangement, so too do certain sequences of chemical bases along the spine of a DNA molecule convey precise instructions for building proteins. The arrangement of the chemical characters determines the function of the sequence as a whole. Thus, the DNA molecule has the same property of “sequence specificity” that characterizes codes and language.
Moreover, DNA sequences do not just possess information in the strictly mathematical sense described by pioneering information theorist Claude Shannon. Shannon related the amount of information in a sequence of symbols to the improbability of the sequence (and the reduction of uncertainty associated with it). But DNA base sequences do not just exhibit a mathematically measurable degree of improbability. Instead, DNA contains information in the richer and more ordinary dictionary sense of alternative sequences or arrangements of characters that produce a specific effect. DNA base sequences convey instructions. They perform functions and produce specific effects. Thus, they not only possess “Shannon information,” but also what has been called specified or functional information.
The Genetic Code
Like the precisely arranged zeros and ones in a computer program, the chemical bases in DNA convey instructions by virtue of their specificarrangement — and in accord with an independent symbol convention known as the genetic code. Thus, biologist Richard Dawkins notes that “the machine code of the genes is uncannily computer-like.”1 Similarly, Bill Gates observes that “DNA is like a computer program, but far, far more advanced than any software we’ve ever created.”2 Biotechnologist Leroy Hood likewise describes the information in DNA as “digital code.”3
After the early 1960s, further discoveries revealed that the digital information in DNA and RNA is only part of a complex information processing system — an advanced form of nanotechnology that both mirrors and exceeds our own in its complexity, design logic, and information-storage density.
Where did the information in the cell come from? And how did the cell’s complex information processing system arise? These questions lie at the heart of contemporary origin-of-life research. Clearly, the informational features of the cell at least appear designed. And, as I show in extensive detail in my book Signature in the Cell, no theory of undirected chemical evolution explains the origin of the information needed to build the first living cell.4
Too Much Information
Why? There is simply too much information in the cell to be explained by chance alone. And attempts to explain the origin of information as the consequence of prebiotic natural selection acting on random changes inevitably presuppose precisely what needs explaining — namely, reams of preexisting genetic information. The information in DNA also defies explanation by reference to the laws of chemistry. Saying otherwise is like saying a newspaper headline might arise from the chemical attraction between ink and paper. Clearly something more is at work.
Yet the scientists who infer intelligent design do not do so merely because natural processes — chance, laws, or their combination — have failed to explain the origin of the information and information-processing systems in cells. Instead, we think intelligent design is detectable in living systems because we know from experience that systems possessing large amounts of such information invariably arise from intelligent causes. The information on a computer screen can be traced back to a user or programmer. The information in a newspaper ultimately came from a writer — from a mind. As the pioneering information theorist Henry Quastler observed, “creation of information is habitually associated with conscious activity.”5
Information and Prior Intelligence
This connection between information and prior intelligence enables us to detect or infer intelligent activity even from unobservable sources in the distant past. Archeologists infer ancient scribes from hieroglyphic inscriptions. SETI’s search for extraterrestrial intelligence presupposes that information embedded in electromagnetic signals from space would indicate an intelligent source. Radio astronomers have not found any such signal from distant star systems. But closer to home, molecular biologists have discovered information in the cell, suggesting — by the same logic that underwrites the SETI program and ordinary scientific reasoning about other informational artifacts — an intelligent source.
DNA functions like a software program and contains specified information just as software does. We know from experience that software comes from programmers. We know generally that specified information — whether inscribed in hieroglyphics, written in a book, or encoded in a radio signal — always arises from an intelligent source. So the discovery of such information in the DNA molecule provides strong grounds for inferring (or detecting) that intelligence played a role in the origin of DNA, even if we weren’t there to observe the system coming into existence.
Next, “The Logic of Design Detection.”
- Richard Dawkins, River out of Eden: A Darwinian View of Life (New York: Basic, 1995), 17.
- Bill Gates, The Road Ahead (New York: Viking, 1995), 188.
- Leroy Hood and David Galas, “The digital code of DNA,” Nature 421 (2003), 444-448.
- Stephen Meyer, Signature in the Cell: DNA and the Evidence for Intelligent Design (San Francisco, CA: HarperOne, 2009), 173-323.
- Henry Quastler, The Emergence of Biological Organization (New Haven, CT: Yale University Press, 1964), 16.