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Our future, our universe, and other weighty topics


Thursday, January 23, 2014

The Origin of Life “Breakthrough” That Isn't

Today the very popular web site digg.com has a link to a story about an MIT assistant professor who seems to think he has come up with a big, important breakthrough regarding the origin of life. The digg.com site has the sensational breathless headline Did This Guy Figure Out How Life Came From Matter? When we open the link we find an article that begins by saying, “Jeremy England, a 31-year-old physicist at MIT, thinks he has found the underlying physics driving the origin and evolution of life.”

There is then a summary of England's ideas, with a link to a paper he wrote, and to a Powerpoint-style pdf file that he created. England has some complicated reasoning designed to show that there may be thermodynamic heat-related reasons why molecules might change or make copies of themselves in order to achieve heat dissipation. I have no idea whether England's basic idea is correct, but I think even if it is correct, it is light-years away from being an explanation for how life came from matter.

Here are the most basic components of life:
  1. The genetic code. This is a symbolic or semantic system wherein certain combinations of nucleotides represent particular amino acids, quite similar to the way that certain combinations of letters (such as DOG) represent particular objects.
  2. DNA and RNA molecules. These are not just complicated molecules, but molecules that use the genetic code. Each DNA molecule is a kind of instruction book on how to make a particular type of life, and that book is written in the language of the genetic code.
  3. Cells. These read the instructions in the DNA molecules, and use them to create proteins from amino acids. Cells have to “understand” the genetic code as well as the DNA and RNA molecules do.
Explaining the origin of all of this ends up being an incredibly difficult problem, and England's work does very little to help solve this problem. England claims to have found reasons why certain molecular systems might tend to reach a more organized state because of thermodynamic reasons. So what? You can explain how water becomes more self-organized when it freezes, but that is not relevant to the origin of life.

One of the key issues in the origin of life is whether or not there would have existed the building blocks needed for the appearance of the first RNA molecules. As explained here, there are reasons for doubting that there would have existed the ribose sugars, nucleotides, and nucleosides needed for RNA molecules to originate. Does England discuss the issue? No, he apparently says nothing about the chemical state of the Earth at the time of the origin of life.

Another difficult thing to explain is the origin of the genetic code. How did mere chemicals turn into the semantic representation system needed for the origin of life, before Darwinian evolution began? England gives us zero insight on this issue, which he completely ignores. England's paper doesn't even mention the genetic code. The word “genetic” does not even appear in his paper. Nor does his 70-page PDF file contain any use of the word “genetic” or the phrase “genetic code.”

Does perhaps this “origin of life breakthrough” have at least some observations or experiments to back it up? No, there are none. Neither the scientific paper nor the PDF file mentions any new observations or experiments. It's all pure math and physics equations.

Does England perhaps have some chemistry breakthrough that will explain the great mystery of how we got the “miniature programming language” of the genetic code or RNA from mere chemicals? No, apparently neither his PDF file nor his paper has any chemistry at all in it – it's all pure physics.

In this link England is quoted as saying this: “You start with a random clump of atoms, and if you shine light on it for long enough, it should not be so surprising that you get a plant.” I think this naive statement shows a lack of insight about the huge problems involved in explaining the origin of life. A problem of explaining the origin of a hugely complicated, well-coordinated system and its semantic framework of the genetic code (with many parts working in harmony) is apparently reduced in England's mind to a problem of getting some more random atoms to combine.

Here is how most scientists view the relation of the main sciences: physics gives rise to chemistry and chemistry gives rise to biology. The thesis can be stated like this:

Physics → Chemistry → Biology

Although true to some extent, this thesis fails to explain all of biology, because we really don't understand properly how biology can get started from mere chemistry. But one thing seems very clear to me: you will never be able to explain the origin of biology by skipping chemistry, and trying to go straight from physics to biology. 
 
So work such as England's, using nothing but physics, will never be a real explanation for the origin of life. The visual below illustrates my point.