Transcendent Life?

A reader recently wrote to ask whether she could purchase an article—specifically the cover story in the Aug. 21, 1967, issue—from the C&EN Archives. The answer, of course, is that she could, for $10. (As of January 2012, ACS members will be able to download 25 journal papers, book chapters, and C&EN Archives stories for free each year.)

C&EN Deputy Editor-in-chief Maureen Rouhi got the e-mail, and she brought the article to my attention. Its title is “Life Transcending Physics and Chemistry,” and it is a 13-page, lavishly illustrated (for C&EN), philosophical essay by Michael Polanyi, one of the seminal scientist/philosophers of the 20th century. It is not the kind of essay I associate with C&EN.

I spent most of that evening reading and re-reading Polanyi’s essay and thinking about it. He makes two central points early in the essay, the first concerning DNA. “A DNA molecule essentially transmits information to a developing cell,” he writes. “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.”

He also writes, “I differ … from most biologists by holding that no mechanism—be it a machine or a machinelike feature of an organism—can be represented in terms of physics and chemistry. This principle precludes the possibility of biology ever becoming a molecular science.”

I think it is clear that advances over the past 40 plus years show that Polanyi was wrong—biology has become a molecular science. What fascinates me is trying to understand why he was wrong because he was a very sophisticated thinker.

In an argument that is far too complex to reprise here, Polanyi makes a strong case that the origin of any particular genetic sequence, and, by extension, the origin of life itself, cannot be explained on the basis of chemical and physical principles alone. However, when he uses the analogy between DNA and a book to state that transmission of genetic information “is nonchemical and nonphysical,” he is mistaken. Genetic information is encoded in DNA’s structure, and while we might not be able to determine the provenance of that information through chemical and physical principles, transcription itself is a profoundly chemical process that we now understand in quite some detail.

Likewise, when Polanyi compares biological structures to machines and insists that both are irreducible to chemical and physical principles, he is arguing at the level of cells and organs. With the structure of a molecular machine like the ribosome in hand, its form and function are, in fact, wholly described by chemical and physical principles.

Polanyi writes, “The machine is a machine by having been built and being then controlled according to the principles of engineering. The laws of physics and chemistry are indifferent to these principles; they would go on working in the fragments of the machine if it were smashed.” He continues, “Returning now to living beings, we may start by observing that to speak of life as something to be explained by the laws of physics and chemistry is strictly speaking absurd, for physical and chemical processes do not determine by themselves any finite system.” In the realm of molecular machines operating within the well-defined confines of living systems, this assertion simply isn’t true. If a ribosome were figuratively smashed, some aspects of its chemistry would cease to function; as a machine, its “engineering principles” are indistinguishable from its chemistry.

If this seems somewhat esoteric, Polanyi’s arguments, or ones very similar to them, continue to resonate with some nonscientists who object to aspects of the scientific endeavor to fully understand life (C&EN, June 4, 2001, page 56).

I’ll return to another interesting aspect of this 1967 issue of C&EN in next week’s editorial.

Thanks for reading.

Author: Rudy Baum

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  1. I haven’t read the article, but are you sure Polanyi wasn’t simply criticizing reductionism in biology? Polanyi was well-known for arguing (in other articles from the 60s for instance) that the structure and function of DNA are as much constrained by higher-order processes as they are by the basic chemistry of phosphates and nucleotides. If that’s what he is saying then I completely agree with his assertion that biology is not a wholly molecular science. There are several emergent properties of biological systems that cannot be uniquely reduced to their molecular foundation. For instance, the chemical reactions involved in transcription and translation can tell us nothing about when and why certain genes are expressed.

    I find it hard to believe that Polanyi, writing in 1967, was unaware of the spectacular advances in biology that molecular approaches had made possible until then. So I am not sure whether he is completely rejecting a physiochemical basis for life or whether is just saying that the underlying laws of physics and chemistry don’t uniquely code for the higher-order functions of life (in which case he is simply saying that the “how” does not tell us much about the “why”). If it’s the latter than I agree with him.

  2. @Curious Wavefunction: Polanyi wrote exactly what I quoted him as writing: “This principle precludes the possibility of biology ever becoming a molecular science.” He did not assert it could not be “a wholly molecular science”; he asserted that it could never be a molecular science.

    I think Polanyi’s analogy between a book and a DNA is also fundamentally flawed. A book’s information content is encoded in a symbolic logic of language. There is nothing symbolic about the information content of DNA–it’s entirely embedded in DNA’s structure. As to transcription and translation, are you suggesting that something other than chemical reactions are involved in turning on or off gene expression?

    I did not suggest that Polayni rejected a physicochemical basis of life in the essay published in C&EN. He said that biology could never be a molecular science, and in that, he was wrong. I don’t know where you draw the line between higher-order functions of life that fall into the “how” category of things and those that fall into the “why” category.