DNA contains no information

Regan Penaluna writes: When we talk about genes, we often use expressions inherited from a few influential geneticists and evolutionary biologists, including Francis Crick, James Watson, and Richard Dawkins. These expressions depict DNA as a kind of code telling bodies how to form. We speak about genes similarly to how we speak about language, as symbolic and imbued with meaning. There is “gene-editing,” and there are “translation tables” for decoding sequences of nucleic acid. When DNA replicates, it is said to “transcribe” itself. We speak about a message — such as, build a tiger! or construct a female! — being communicated between microscopic materials. But this view of DNA has come with a price, argue some thinkers. It is philosophically misguided, they say, and has even led to scientific blunders. Scratch the surface of this idea, and below you’ll find a key contradiction.

Since the earliest days of molecular biology, scientists describe genetic material to be unlike all other biological material, because it supposedly carries something that more workaday molecules don’t: information. In a 1958 paper, Crick presented his ideas on the importance of proteins for inheritance, and said that they were composed of energy, matter, and information. Watson called DNA the “repository” of information.

Less than a decade later, George Williams, an influential evolutionary biologist, elaborated on this idea. He described genes to have a special status distinct from DNA, and to be the message that the DNA delivers. In a later work, he likened genes to ideas contained in books. A book can be destroyed, but the story inside is not identical to the physical book. “The same information can be recorded by a variety of patterns in many different kinds of material. A message is always coded in some medium, but the medium is really not the message.” In his book The Blind Watchmaker, Dawkins gives perhaps the most forthright description of this view: “airborne willow seeds… are, literally, spreading instructions for making themselves… It is raining instructions out there; it’s raining programs; it’s raining tree-growing, fluff-spreading, algorithms. That is not a metaphor, it is the plain truth. It couldn’t be any plainer if it were raining floppy discs.”

But do genes truly contain information in the same sense as words, books, or floppy discs? It depends on what we mean by information. If it’s the meaning represented by the words, books, or floppy disks, then no. Many philosophers agree that this kind of semantic information requires communication: an agent to create the message and another to interpret it. “Genes don’t carry semantic information, though. They weren’t made as part of an act of communication. So genes don’t literally represent anything, as people sometimes say,” explains Peter Godfrey-Smith, a professor of philosophy at CUNY. [Continue reading…]

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