Evolution News and Views (ENV) provides original reporting and analysis about the debate over intelligent design and evolution, including breaking news about scientific research.

Evolution News and Views
Intelligent Design NEWS
 

Stephen Meyer at the University Club: Why Are We Still Debating Darwin?

Signature in the Cell

In his "Socrates in the City" talk in Washington last week, Steve Meyer asked: "Is there a scientific controversy about the theory of evolution?" After quoting many spokesmen for official science who deny the existence of any such controversy, or any reason to doubt evolutionary theory whatsoever, Meyer showed that there are significant reasons to doubt both biological and chemical evolutionary theory.

He first addressed the problems associated with chemical evolutionary theory, which "attempts to explain the origin of the first life from simpler pre-existing chemicals." Here he explained the critical question of the origin of genetic information. This is the problem he addressed in his book Signature in the Cell, a problem that has beset all attempts to explain the origin of life by reference to undirected chemical evolutionary processes.

The most important idea for laymen to grasp is that of biological information. It's difficult to understand "exactly what information is," Meyer has written. It's not a physical thing. He quotes the evolutionary biologist George Williams as saying that information "doesn't have mass or charge or length," and matter "doesn't have bytes." It follows that matter and information belong to "two separate domains."

Information in biology is best understood as analogous to software code. Recall Bill Gates's comment: "DNA is like a computer program but far, far more advanced than any software ever created."

Software is a set of instructions for a new program in a computer. Likewise, DNA contains a set of instructions for the assembly of parts, namely proteins, within a cell. In the 19th century the cell was thought to be simple. Darwin and his contemporaries had no way of knowing just how complex it was. The cell today is sometimes compared to a high-tech factory. (Except it's much more complex than that -- factories can't replicate themselves.)

Here is the key question: How did the requisite information get into the DNA in the first place? Without it, the first cell would never have been constructed and life would never have started. So the question about information is closely related to the question: How did life begin?

Charles Thaxton, a co-author of The Mystery of Life's Origins, told Meyer that the origin-of-life question is still unanswered. When Ben Stein asked Richard Dawkins in Expelled how life began, Dawkins said he had no idea. Stanley Miller performed a famous experiment in 1952 showing that some amino acids can be generated artificially, but that was as far as they could get. They were far short of life itself. (And even Miller's experiment has been criticized for not simulating actual conditions on the early Earth.)

Nucleotides arrayed along the backbone of the DNA molecule form triplets called codons. In the language of the genetic code, these three-digit codons are commands that the cell interprets when constructing proteins. There are codons that signify start commands, stop commands, and codons for signaling each of the 20 amino acids used in proteins. They convey information by virtue of their sequence, not their chemical properties. DNA is like written language in that respect. For example, both s-a-l-t and l-a-s-t contain the same four letters, but convey different meanings based on their sequence alone. When sequenced correctly, nucleotides in the DNA instruct the cell to use its molecular machinery to link amino acids into proteins. The precise sequence of these amino acids, specified by the DNA, is crucial to ensuring that a protein is properly assembled and functional. That's how DNA embodies functional information.

In 1953 Watson and Crick described the double helical structure of DNA but no one has yet explained the origin of the information DNA contains. This creates a problem for those trying to explain the origin of life as a result of undirected processes. If the nucleotide sequence in the DNA were different, proteins wouldn't function, or they probably would not even get built to begin with. "So the information in DNA and its companion molecule RNA is a huge stumbling block for evolution," Meyer said.

He mentioned the famous Dawkins comment that biology is the study of complex things that appear to have been designed for a purpose. But we are talking about actual, not apparent design. No undirected chemical process that we know of can produce the information necessary to account for the origin of the first living cell.

Just as useful computer code comes from programmers, so functional information comes from intelligence. It comes from mind, said Charles Thaxton. Darwin's geologist friend, Charles Lyell, said that in trying to understand events in the remote past, we should look for causes now in operation. Mind fits that bill. Intelligence, or mind, or conscious activity, is the only known cause of the kind of sequence-specific, information-rich code that we see in biology.

Thus, we infer that the ultimate origin of biological information is best explained as proceeding from the design of an intelligent agent or agents. All other proposed explanations have failed; none cites a cause that is known to produce information.

Meyer said a few words about the reaction to Signature in the Cell. No one has demonstrated that there is a better chemical evolutionary explanation for the appearance of information, said Meyer. Some critics insist that Darwinian mechanisms can get the job done. But processes such as natural selection can't take place until life is already up and running. "Invoking biological evolution is to miss the whole point of the book," Meyer said.

Until we have a living and self-replicating cell, we have no way of introducing natural selection into the picture. "Nothing I've said to this point challenges Darwin directly," Meyer added. But then Darwin himself never successfully refuted the design argument. Nor do those who cite Darwinian processes.

At this point, Meyer transitioned to the second part of his talk. Here he explained that biological evolutionary theory, which "attempts to explain how new forms of life evolved from simpler pre-existing forms" also faces formidable difficulties. In particular, the modern version of Darwin's theory, or neo-Darwinism, also has an information problem. The mutation and natural selection mechanisms have failed to explain the origin of the new information necessary to build fundamentally new forms of life, or even just new proteins.

Before going on, Meyer distinguished three meanings of evolution. First "change over time," which no one disputes. Second, the claim that this change has occurred in a continuous way, giving us the "branching tree picture" that was the only diagram in The Origin of Species. Third we have natural selection with mutation, or "copying errors in the DNA." They are analogous to copying errors in digital code.

The errors change the information in the DNA, supposedly providing the grist for natural selection. "We are expected to believe that random mutations provide the new information that is necessary to build new proteins, new cells, new traits, organs and tissues that arise in the process of evolution," Meyer said. But can natural selection generate enough information to build new forms of life?

In a "sneak preview," Meyer said his next book would be about the Cambrian explosion -- the geologically sudden appearance of most of the major animal forms and body designs. It is a dramatic event in the history of life; new body plans -- for example arthropods, chordates and brachiopods -- appeared suddenly about 530 million years ago. There's a geological stratum in China where many new animal phyla appear within a few million years. This pattern doesn't match that "continuously branching tree" that Darwin drew. Nothing that can plausibly be called a precursor appears in the strata below the Cambrian.

More importantly, the same information problem arises: What would it take to build one of those new body plans? "You need a big instruction set, just for one body part." The trilobite has a compound, lens-focusing eye. "Each new cell for each new tissue had dedicated proteins. And the proteins in turn need instructions for them to be built." It's hard to believe that mutation could generate the new information required.

Random changes in DNA are supposed to generate new sections of code. But how? Meyer discussed the 1966 Wistar Institute symposium in which MIT mathematicians and others expressed doubts about the plausibility of the story.

We have already seen that DNA and software must have something called "sequence specificity" if they are to provide functional information.

"What we know from all codes and languages is that when we are dealing with specificity of sequence as a condition of function, random changes degrade function much faster than they ever come up with something new," Meyer said.

There's a combinatorial problem. A bike lock with four dials and ten digits gives 10,000 possibilities, only one of which opens the lock. Ten dials would give us 10 billion possibilities. But the protein alphabet has 20 possibilities at each site and the average protein has about 300 amino acids in sequence.

Meyer explained that, in the case of proteins, unlike the bike lock, there are many functional arrangements of amino acids among the possible combinations. Nevertheless, the ratio of functional sequences to the total number remains prohibitively small. How rare are the functional sequences? A colleague of Meyer's, Doug Axe, with a PhD from Caltech, looked into this question while doing research at Cambridge University.

Using the method of Site Directed Mutagenesis, Axe found the ratio of functional to all possible sequences for a protein 150 amino acids in length to be an absurdly small 1 to 1074. That search space is larger than the number of atoms in the Milky Way galaxy. So we have a "hideous search problem." Multiplying that low probability by the total number of organisms reduces the problem somewhat, but not enough to make it remotely plausible that mutation and natural selection could produce one functional protein of modest length during entire history of life on earth.

Not just any old jumble of amino acids makes a protein. Similarly, chimps typing at keyboards will have to type for a long time before they get a complete, error-free, meaningful sentence of 150 characters. They'll get letters of the alphabet because they use typewriters. The problem is they have to get the letters in the right order. The required sequence is both complex and specified.

"Lots of biophysicists are aware of the problem," Meyer said. "We have a small needle in a huge haystack. It's a problem that neo-Darwinism has not solved. And notice that there's a mathematical rigor to this which has not been a part of the so-called evolution-creation debate."

Meyer concluded by emphasizing that there is a huge disparity between the alleged consensus about contemporary evolutionary theory and the many formidable, and increasingly quantifiable, problems with the theory that are known in the technical scientific literature.