Does the information in DNA point to a designer?

DNA stores the instructions for building proteins in a four-character chemical code. Just as letters convey a message by their arrangement, Meyer writes, particular sequences of bases along DNA convey precise instructions for building proteins, the property Francis Crick’s “sequence hypothesis” described^{[source 1]}.

Meyer’s argument, developed at length in Signature in the Cell (2009), concerns the origin of the first living cell, before natural selection could operate^{[source 2]}. He argues that chance is far too improbable to produce the information in even a minimal cell, that chemical laws cannot explain it because DNA’s sequence is not dictated by chemical attraction between its parts, and that no theory of undirected chemical evolution has explained it^{[source 1]}.

Meyer treats the possible explanations in turn. Chance alone, he argues, is ruled out by the vast number of possible sequences compared with the tiny fraction that produce working proteins. Chemical necessity is ruled out because the bases can attach along the DNA backbone in any order, which is what lets DNA carry information in the first place. Combinations of chance and selection, he argues, cannot help before there is a self-copying system for selection to act on, and he contends that proposals such as the RNA world presuppose the very information they are meant to explain^{[source 1][source 2]}.

His case is meant to be positive, not only a gap. Drawing on William Dembski’s concept of specified complexity^{[source 3]}, he argues that in our uniform experience, information of this kind arises from minds: a computer program from a programmer, a newspaper from a writer^{[source 1]}. He compares the inference to the search for extraterrestrial intelligence, which would treat an information-bearing radio signal from space as evidence of an intelligent source^{[source 1]}.

Meyer also argues that resistance to design is philosophical rather than evidential. When the Big Bang theory first implied that the universe had a beginning, he writes, many scientists disliked its implications but accepted it because the evidence supported it; “today a similar metaphysical prejudice confronts the theory of intelligent design,” which he says must likewise be judged on the evidence^{[source 1]}.

Critics’ first objection is that the argument rests on what origin-of-life research has not yet explained. No researcher proposes that a cell assembled by chance; Pross and Pascal, for example, describe chemical selection among replicating molecules, in which more stable replicating systems tend to win out, as the route by which chemistry could become biology^{[source 5]}. Critics read progress of this kind as reason to keep looking for a natural explanation rather than to conclude design.

Second, critics dispute the concept of information. Wesley Elsberry and the computer scientist Jeffrey Shallit argued that Dembski’s “complex specified information” is not a well-defined quantity that can be calculated for biological systems, and that his arguments contain significant errors^{[source 3][source 4]}. Shallit also points to experiments and simulations in which evolutionary processes increase information, contrary to Dembski’s claims^{[source 3]}. Dembski and the engineer Robert Marks reply that successful evolutionary simulations work only because their programmers build in information about the target, which they call active information^{[source 8]}.

Shallit adds that information in the ordinary, measurable sense can increase through evolutionary processes. He cites Thomas Schneider’s computer simulation showing how Shannon information may increase under mutation and selection^{[source 3]}. Dembski described Schneider’s work as smuggling in information that only appeared to be generated for free; Shallit replies that Schneider never claimed to be producing Dembski’s complex specified information in the first place, so the charge misses its target^{[source 3]}.

Third, critics question the analogy behind the inference. The information in human artifacts comes from minds we already know exist and can observe at work; the origin of life was a one-time event in the remote past. Extending the analogy to an unobserved designer, they argue, goes beyond what experience can support, an objection to design arguments that goes back to David Hume^{[source 6]}. Meyer replies that his inference rests on what is known about the causes of information, not on an analogy: intelligence is the only cause known to produce it^{[source 1]}.

How life began remains unsolved; Addy Pross and Robert Pascal call it “one of the more challenging scientific questions of all time”^{[source 5]}. Meyer’s argument addresses a real open question, and his critics agree on that much. They disagree over whether an unsolved problem is evidence for design or a research program still under way.

Origin-of-life researchers have proposed general principles to guide the search. Pross and Pascal argue that “all stable (persistent) replicating systems will tend to evolve over time towards systems of greater stability,” where the stability that matters is the dynamic kind found in systems that keep copying themselves, not the static stability of ordinary chemistry^{[source 5]}. Whether principles like this can account for the information in the first cell is exactly what remains open.

Meyer’s design inference has not been adopted in origin-of-life research, and Dembski’s measure of specified information has not been taken up in information theory^{[source 3][source 4]}. Proponents argue that this reflects the field’s commitment to finding only natural causes^{[source 2]}.