As a result of the failure of the chance hypothesis to explain the origin of life, Dean Kenyon and Gary Steinman proposed a novel solution: life’s origin is due to physical necessity, not chance (Biochemical Predestination, 1969).  Like many others in their day, Kenyon and Steinman were proponents of the protein-first model, maintaining that the first life was based on proteins rather than DNA (DNA came later).  They got around the utterly implausible odds of forming proteins by chance by just denying that chance was involved at all.  They suggested that law-like processes direct the self-organization of chemicals, making the origin of life inevitable, not some lucky happenstance.  Just like electrostatic forces draw sodium and chloride together in ordered patterns to form crystals, some (yet-to-be-discovered) natural law organized biochemicals to form the biological information that makes life possible. 

As evidence for their view that proteins could self-organize to form the basis of life, they pointed to the fact that amino acids bond with certain other amino acids better than others, making certain sequences more likely than others.  This explained how the biological information necessary for life could arise without DNA, RNA, and the transcription-translation process.[1]

Eventually, however, Kenyon came to question his model.  He recognized that even if it could explain the origin of biological information, he still needed to explain the origin of DNA as well as how protein synthesis transformed itself from a self-organizing and self-originating process to one that depended entirely on DNA transcription and translation.  He dismissed the possibility that proteins constructed DNA because the information flow in modern cells is unidirectional, and it’s in the complete opposite direction: information flows from DNA to proteins, not vice-versa.  Because DNA wholly determines the amino acid sequencing of proteins, and because there is no evidence suggesting or reason to think this order was ever different in the past he eventually abandoned the protein-first model.  DNA must have come first.  But based on his knowledge of its chemical properties, he doubted that DNA possessed the same sort of self-organizational properties he thought were present in amino acids.  He was forced by the evidence to abandon his proposal that life originated by necessity.

Interestingly, the year before Kenyon and Steinman published their theory that life originated by chemical necessity, Michael Polanyi wrote a brilliant essay in which he argued that the laws of physics and chemistry cannot, in principle, explain the origin of biological information.  Physical laws cannot determine the arrangement of the chemical constituents of life anymore than the laws of physics determine how ink is arranged on paper to convey information.  As Polanyi explained in a later paper:

Biological systems, like machines, have…functions and forms inexplicable by chemical and physical laws. The argument that the DNA molecule determines genetic processes in living systems does not indicate reducibility. A DNA molecule essentiality transmits information to a developing cell. Similarly, a book transmits information. But the transmission of the information cannot be represented in terms of chemical and physical principles. In other words, the operation of the book is not reducible to chemical terms. Since DNA operates by transmission of (genetic) information, its function cannot be described by chemical laws either. The life process is essentially the development of a fertilized cell, as the result of information imparted by DNA. Transmission of this information is nonchemical and nonphysical, and is the controlling factor in the life process. The description of a living system therefore transcends the chemical and physical laws which govern its constituents.”[2]

If biological information cannot be reduced to chemicals and laws, it could not have originated from them either.  The fact of the matter is that the laws of physics allow for a large number of chemical arrangements, the overwhelming majority of which convey no information whatsoever. 

More importantly, Polanyi pointed out that law-like processes directing chemical bonding would actually prohibit the generation of information.  Laws determining the bonding of chemicals would invariably produce repetitive regularities.  So if some natural law required that guanine bond to cytosine, thymine bond to guanine, adenine bond to thymine, and cytosine bond to adenine, the only possible DNA sequence would be “CGTA” which would appear repetitively along the DNA backbone.  Information, however, requires specified variability (irregularities).  It is oxymoronic to think regularity can explain irregularity.  If natural laws determine the bonding properties of DNA and/or amino acids—and hence their arrangement—DNA would be incapable of generating the variability required to originate biological information.  Even if the CGTA-CGTA-CGTA repetitive sequence was biologically meaningful, every gene would code for the same protein.  Life, however, requires a wide array of proteins to carry out all the functions of the cell.

To illustrate the problem, consider the English alphabet.  If some grammatical law governed our alphabet so that out of necessity, whenever we write the letter A it must be followed by the letter D, and whenever we write the letter D it must be followed by the letter Y, and whenever Y then L, whenever L then J, whenever J then Q, whenever Q then E and so on, it would be impossible to convey meaningful information.  For example, if I wished to communicate that “a cat walked past my house today,” once I wrote “A” I would have to follow it by “DYLJQE.…”  Such grammatical laws would create repetition and meaninglessness, not information.  The same is true of the DNA and amino acid alphabets.  Since life requires information, and information requires specified variability, DNA and/or proteins cannot be the product of law-like self-organization.

For Meyer, the final nail in the coffin for self-organization models is the structure of the DNA molecule itself.  Self-organizational models require that there be multiple chemical bonds of differing strength that are capable of determining a specific arrangement of chemicals.  The DNA molecule, however, lacks the chemical bonds necessary to create such bonding affinities.  There is only one chemical bond (N-glycosidic bond) that bonds each nucleotide base to its binding site on the sugar-phosphate backbone, so there is no chemical property along either of the two backbones that can determine the order in which nucleotides bind to it.[3]  Any of the four nucleotide types can attach themselves to any binding site on the backbone with equal ease, no one being favored over another. 

While there are no bonding affinities on the backbone of DNA that can determine nucleotide sequencing, are there any bonding affinities between the nucleotide pairs along the longitudinal axis in the center of the molecule that might do so?  No.  While there is a weak hydrogen bond between the two nucleotides that form nucleotide pairs (between adenine and guanine, and between cytosine and thymine), there are no chemical bonds between the nucleotides along the longitudinal axis in the center of the molecule where the genetic information is stored.  Without any chemical bonds linking one nucleotide/nucleotide pair to the nucleotide/nucleotide pair above and below it, there is nothing to necessitate that the nucleotides be arranged in any particular order.  So even if there was some natural law that could cause chemicals to self-organize, the DNA molecule lacks the necessary properties on which this law could act (the same is true of RNA).  

In the same way that natural laws can cause magnetic letters to stick to a magnetic board but are incapable of determining that they be arranged to spell out a meaningful message such as “Take out the trash when you get home,” natural laws may explain the properties of the chemicals necessary for life but they are wholly incapable of determining that they arrange themselves into biologically meaningful information.  Information cannot be explained by, or attributed to law-like forces.  There is only one known source for generating information: intelligent agency.  In the same way that an intelligent agent is required to arrange the chemical properties of ink to communicate functionally meaningful information, and in the same way an intelligent agent is required to arrange the letters on a magnetic board to convey functionally meaningful information, so too it stands to reason that an intelligent is required to arrange nucleotides into sequences capable of conveying biologically meaningful and functional information. 

As an explanation for the origin of life, both chance and physical necessity are bankrupt.  But what if they work together?  Could they get the job done?  We’ll address this question in the next installment, focusing on the prevailing theory of life’s origin: the RNA World hypothesis.


[1]Even if self-organization theories could explain the origin of biological information in DNA, they would still have to explain the origin of the transcription and translation process.  How did RNA originate, and how did it come to acquire the function of unwinding and transcribing genetic information?  How is it that there arose a precise correspondence between the codons (nucleotide triplets) on mRNA and amino acids (carried by tRNA)?
[2]Michael Polanyi, “Life Transcending Physics and Chemistry,” Chemical & Engineering News, Vol. 45, No. 35, August 21, 1967, pp.54-66, p.56.
[3]The backbone is itself held together by a sugar-phosphate bond, and each of those bonds is bonded to the sugar and phosphate above and below it.