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On Prebiotic Chemistry, Synthetic Chemist James Tour Urges an Admission of Ignorance

Tour Waterloo.jpg

Last time we checked in with Rice University’s great synthetic chemist James Tour, he had just delivered a slashing lecture at the University of Waterloo on the problem of life’s origin. The specific theme was how “clueless” science actually is about abiogenesis, the enigma of life from nonlife. He apologized for a “painfully technical” approach, but added, “I simply know of no other way to expose the hypocrisy of the conjectures based on the evidence.”

That was intense enough. Now writing in the online journal Inference, he turns up the heat by a few clicks (“Animadversions of a Synthetic Chemist“). It’s an awesome performance, painfully technical in places, but the pain is mitigated because it turns out the guy can write.

Taking aim at biologists who assume the matter of prebiotic chemistry is well in hand, he sets out this way:

Life requires carbohydrates, nucleic acids, lipids, and proteins. What is the chemistry behind their origin? Biologists seem to think that there are well-understood prebiotic molecular mechanisms for their synthesis. They have been grossly misinformed. And no wonder: few biologists have ever synthesized a complex molecule ab initio. If they need a molecule, they purchase molecular synthesis kits, which are, of course, designed by synthetic chemists, and which feature simplistic protocols.

Polysaccharides? Their origin?

The synthetic chemists do not have a pathway.

The biologists do not have a clue.

As Howard Glicksman emphasizes in his “Designed Body” series here at Evolution News, evolutionary biologists can describe things but are less well equipped to describe what it take for those things to work. That’s where the insights of a physician like Dr. Glicksman, or an engineer — see this morning’s post by Steve Laufmann — come in.

So too, a synthetic chemist understands the difficulties of OOL in a way other scientists really can’t:

Chemists study molecules. Synthetic chemists make them. What nature does is anyone’s guess. The molecules that we make are made to perform certain functions. The initial design is important. Sometimes molecular designs are computer-assisted, but more often than not, the initial steps are done on paper. A target must first be drawn or otherwise designated. This is no trivial task. In some cases, chemists have seen the target in a related system; in other cases, they guess the target’s properties on the basis of its molecular weight, its shape, its addends, and its functional capacities.

This is just the beginning.

The essay is long and rich — I won’t pretend to do it justice. Read it, in part because as I said, Tour can turn a phrase.

So far as life goes, as Teacher’s is the great Scotch, water is the great solvent.

The article isn’t an argument for intelligent design, but, instead, for humility. Also, for honesty. Writes Dr. Tour, who designs nanocars and nanotrucks:

In nature, molecular structure is confirmed by using complex molecules, the process akin to a glove fitting a hand. Whence that glove? It, too, had to be derived from a biological synthesis, with confirmation of its structure by a yet another glove that recognized its precise sequence, shape, and stereochemistry.

Designing nanoncars is child’s play in comparison to the complexity involved in the synthesis of proteins, enzymes, DNA, RNA, and polysaccharides, let alone their assembly into complex functional macroscopic systems. There are apparently a great many gloves in nature.

Like Teacher’s Scotch, this part may burn a bit going down if you’re not accustomed to it:

The world’s best synthetic chemists, biochemists, and evolutionary biologists have combined forces to form a team — a dream team in two quite distinct senses of the word. Money is no object. They have at their disposal the most advanced analytical facilities, the complete scientific literature, synthetic and natural coupling agents, and all the reagents their hearts might desire. Carbohydrates, lipids, amino acids, and nucleic acids are stored in their laboratories in a state of 100% enantiomeric purity.

Would the dream team — please — assemble a living system?

Take your time, folks, take a few billion years.

Nothing? Well, well, well.

Let us assume that all the building blocks of life, and not just their precursors, have been made to a high degrees of purity, including homochirality where applicable — the carbohydrates, the amino acids, the nucleic acids, and the lipids. They are stored in cool caves, away from sunlight, and away from oxygen. These molecules are indifferent to environmental degradation.

And let us further assume that they are all stored in one comfortable corner of the earth, not separated by thousands of kilometers or on different planets.

And that they all exist not just in the same square kilometer, but in neighboring pools where they can conveniently and somehow selectively mix with each other as needed.

Now what? How does the dream team assemble them without enzymes?

Very well. Give the dream team polymerized forms: polypeptides, all the enzymes they desire, the polysaccharides, DNA and RNA in any sequence, cleanly assembled.

Ready now?

Apparently not.

He concludes:

Those who think scientists understand the issues of prebiotic chemistry are wholly misinformed. Nobody understands them. Maybe one day we will. But that day is far from today. It would be far more helpful (and hopeful) to expose students to the massive gaps in our understanding. They may find a firmer — and possibly a radically different — scientific theory.

The basis upon which we as scientists are relying is so shaky that we must openly state the situation for what it is: it is a mystery.

You mean in informing impressionable students on questions of origins, it may be a legitimate option, even an advisable one, to frankly admit that science doesn’t have everything all figured out? Not even close? Acknowledge that the most fundamental question of all, how life came about, remains thoroughly obscure, plagued by “massive gaps in our understanding”? You mean tell the truth, instead of lying? Well, well, well. What a concept.

Photo: James Tour, courtesy of University of Waterloo via YouTube.