Is DNA Really Information, or Is That Just a Metaphor?
Words such as information, code, transcription, translation, editing, and proofreading are common in molecular biology.
But does this language describe something objectively present in the cell, or are scientists simply borrowing convenient metaphors from human communication and computers?
If biological information is only a metaphor, an argument for design based upon information could appear to rest upon the language used to describe DNA rather than upon the biology itself.
Why This Matters
This objection goes to the heart of the biological-information argument.
If the case for design depends merely upon calling DNA a "language" or the genetic code a "code," then terminology could be mistaken for evidence.
We therefore need to distinguish the metaphors used to explain molecular biology from the physical relationships that actually occur inside living cells.
Response
Not every use of the word "information" in biology means exactly the same thing. Some uses describe statistical relationships. Others refer to sequence specificity, heredity, regulation, signaling, or functional effects.
Claims that DNA contains messages in precisely the same sense as a written sentence can therefore go beyond what molecular biology establishes.
Nevertheless, there is an objective molecular relationship beneath the terminology. The nucleotide sequence of a protein-coding gene affects the sequence of RNA produced from it. During translation, nucleotide triplets in messenger RNA are related to particular amino acids through transfer RNAs, aminoacyl-tRNA synthetases, ribosomes, and other components of the translation system.
Those sequence-dependent relationships exist regardless of whether we call them a language.
Intelligent Design therefore need not depend upon proving that DNA is literally equivalent to human writing or computer software. The more substantial question concerns the origin of a system in which sequences are stored, copied, recognized, translated, regulated, and connected with biological function.
Question That Remains
How should biological information be defined?
Which informational descriptions identify distinctive properties of living systems, and which are primarily useful analogies?
Most importantly for this investigation, how did the physical system connecting nucleotide sequences with functional molecular outcomes originate?