When Scientific Theorists Use “Prestige by Association” Ploys

There is a persuasion technique that we can call “prestige by association.” The technique is used by someone who tries to give himself extra prestige by associating himself with someone or something more respected, famous, rich, successful or admired. Below are some examples:

1. A person who runs a not-very-reputable investment company will be careful to collect any pictures he can get of himself with well-known or respected people, and to display such pictures as framed photos visible to anyone who comes to his office.
2. A president or political candidate who dodged military service will favor “photo ops” in which he is seen side-by-side with military heroes.
3. A person who had some remote connection with a respected institution will make much mention of this thin connection. For example, a person who merely graduated from a community college, but who later wrote a short article in some magazine published by Harvard may frequently refer to himself as a “Harvard-published author.”
4. An author publishing some nonsensical claims in a book may tell us that the book now resides in the Library of Congress, a claim that may impress people who do not realize that anyone can submit to the Library of Congress a book as long as it is 50 pages long.
5. If your friend knows someone who knows movie star Jennifer Lawrence, your friend may try to trumpet this connection, almost making you think that he is one of Jennifer Lawrence's inner circle – even if Jennifer would never be able to recognize him.

The same “prestige by association” tricks are often used by scientific theorists trying to build up the reputation of some doubtful scientific theory. The strategy is to make your dubious scientific theory sound more credible by trying to establish some association or mental link with some other scientific theory that has more prestige. Below are some examples of how this “prestige by association” trick was used by various theorists:

1. When some theorists advanced the extremely dubious idea that human behavior is strongly influenced or largely controlled by genes, they christened this implausible theory “behavioral genetics,” thereby trying to borrow some of the prestige of the well-established science known as genetics.
2. When theorist Gerald Edelman advanced a complex speculative theory of the brain, he labeled it “Neural Darwinism,” trying to get some prestige by association. But the theory bears little resemblance to anything taught by Darwin.
3. When theoretical physicist Lee Smolin advanced some weird theory that new universes are being formed when black holes collapse, he called this theory “cosmological natural selection,” trying to get some prestige by association from the biological theory of natural selection (even though there is scarcely any resemblance between his non-biological theory and doctrines about natural selection in biology).
4. Theorists trying to bolster the prestige of the Darwinian theory of the origin of species by natural selection will often discuss that theory while discussing very prestigious theories such as special relativity and the theory of electromagnetism that make precise numerical predictions that have been exactly verified. The aim is to leave the reader with the impression that Darwinism is in the same class with such exact mathematical theories. No mention will be made of the fact that Darwinism, unlike such theories, does not make exact numerical predictions that have been verified.
5. The theory of cosmic inflation is a separate theory from the Big Bang theory. The Big Bang theory maintains that the universe arose from an incredibly dense state 13 billion years ago, possibly from a state of infinite density. The cosmic inflation theory is a theory that the universe underwent a super-short phase of exponential expansion during a tiny fraction of its first second. The evidence for the Big Bang theory is pretty good, but there is no good evidence for the cosmic inflation theory. Repeatedly the proponents of the cosmic inflation theory have tried to play “prestige by association” tricks by trying to get people to conflate the fairly well-established Big Bang theory with the purely speculative cosmic inflation theory. They do this by describing the cosmic inflation theory as “the modern version of the Big Bang theory” or “the current version of the Big Bang theory.” Such claims are inaccurate, as the Big Bang theory and the cosmic inflation theory are two separate theories, and evidence establishing the first is not evidence establishing the second. Similarly, proponents of the cosmic inflation theory may refer to it as “the inflationary Big Bang theory,” trying to give their speculative cosmic inflation theory some of the credibility of the Big Bang theory.

Recently the press office of Stanford University has given us another example of scientific theorists playing “prestige by association” games. We have an article in which the author tries to give the completely groundless and entirely speculative “string theory landscape” theory some “prestige by association” by linking it to the Big Bang theory. The article states, “The latest draft of the scientific story of genesis is called the String Theory Landscape,” as if the “string theory landscape” theory was some version of the Big Bang theory. This is entirely false. The “string theory landscape” theory is not a theory of the origin of the universe, and is not a version of the Big Bang theory.

The article also tries to give a much-needed prestige boost to string theory by trying to link it or associate it with the cosmic inflation theory. There are two reasons why this attempt is absurd. The first is that it's a case of trying to bolster the prestige of one empirically groundless theory by associating it with another empirically groundless theory. For just as there is no evidence for string theory, there is no evidence for the cosmic inflation theory (not to be confused with the more general Big Bang theory). So if you're a string theorist trying to bolster your prestige by associating your theory with cosmic inflation theory, it's kind of like some Big Foot theorist trying to bolster his prestige by joining forces with a Loch Ness monster theorist.

Another reason the attempt to bolster the prestige of string theory by associating it with cosmic inflation theory is laughable is that the two theories are unrelated. Cosmic inflation theorists have churned out nearly 1000 different papers giving versions of cosmic inflation theory, and virtually none of these papers ever relied on the assumptions of string theory. String theorists have churned out more than 1000 different papers giving versions of string theory, and virtually none of these relied on the assumptions of cosmic inflation theory. A New Scientist story talks about a study that “suggests it may be difficult to reconcile string theory with the widely accepted theory of inflation.” It quotes a Princeton scientist saying, “I think the fact that it is difficult to combine inflation and string theory is very interesting.”

The Stanford University article gives us this bad reasoning:

This diversity, they say, is key to explaining certain baffling features of our universe, like the fact that several parameters in physics and cosmology appear to be curiously fine-tuned for life forms like us to exist. Perhaps the most glaring example is the cosmological constant, which relates to a universal repulsive force that is pushing space-time apart. Physicists have struggled to explain why the tiny value of this constant just happens to lie within the narrow band that allows stars and planets to form and biological life to evolve. But if there are innumerable universes, each with differing laws of physics, then it should not be surprising that we inhabit one where the cosmological constant is small – if things were any different, we could not exist to marvel at the coincidence.

But actually, it should be incredibly surprising that we inhabit a universe where some vastly improbable set of coincidences occurred, because you don't change the likelihood of such coincidences occurring in any one of those universes by imagining other universes. The likelihood of something very improbable happening in any one random trial does not change by increasing the number of trials (for example, your probability of winning a million dollars at a Las Vegas casino is not increased the slightest if there are a trillion universes filled with casinos). So imagining the “innumerable universes” other than ours is pointless. What's happened is that our string theorists have made an elementary error in logic, confusing the likelihood of “some universe” being fine-tuned for life with the likelihood of “our universe” being fine-tuned for life.

Such elementary errors in logic are not rare among PhD's, such as when biologists suggest that natural selection is the cause of complex biological innovations, when there is no natural selection effect related to a biological innovation (no “survival of the fittest” effect) until after that biological innovation appears. This is the elementary reasoning error of maintaining that a consequence of an effect is the cause of that effect, which is kind of like reasoning that the thundercloud appeared because the city street got soaked by the thunderstorm. We must always remember that a man who has a PhD is just as prone to commit elementary reasoning errors as someone who does not have a PhD. Our different tribes of scientists (such as the string theory tribe)  are belief communities just as much as the Amish and Sikhs and Scientologists are belief communities, and in many a belief community bad reasoning can be so normalized that it may be hard for a member of the community to see how large a logic error he may have committed.

String theory maintains there are 10 or more dimensions of space. This idea has flunked a recent observational test. A recent headline reports, “University of Chicago astronomers found no evidence for extra spatial dimensions to the universe based on the gravitational wave data.”

LIGO gravitational wave detector

Postscript: Stanford University has now completed its five part goofy exposition of the Fake Physics of the "string theory landscape."  Its more laughable parts include:

(1) Scientist Andrei Linde babbling about infinite copies of you in the multiverse. 

(2) A scientist named Dimopoulos making the silly claim that the "richness" of string theory "tells you that there are many universes."

(3) The claim that the "string theory landscape" with 10 to the five hundredth power universes "elegantly explains why the universe appears to be so eerily fine-tuned for life."  The theory doesn't do that, and if you look up the definition of "elegant" you will see that in a scientific context it means a solution that is simple; but nothing could be less simple than imagining 10 to the five hundredth power universes. 

There's a lesson you should derive from the third example (which repeats an untruth discussed here). It is that when scientists say something about one of their theories, the exact opposite may be true. So a theory described as "brilliant" by a scientist may be very stupid; and a theory described as "proven" by a scientist may be groundless and inconsistent with observations. 

Real physics involves equations, and there is no way to ever write an equation that yields another universe or a multiverse.  You never get another universe doing real physics calculations. Multiverse fantasists may try to impress us by writing papers with equations, but none of their equations ever yields another universe after the equal sign. 

Fast Tree: A Science Fiction Story

In the year 2045 Nat Watkins should have been happy with his lot in life. His wife Matilda was a genetic engineer who had invented a product called Fast Trees that was a huge success. The success of the product had made the couple five million dollars.

When Matilda first discussed the idea of genetically engineered Fast Trees with Nat, he told her it would never work. People like natural things in their backyard, Nat argued, not a genetically engineered tree. But Matilda was insistent that the product would succeed. She said the main reason few people plant trees in their back yards is that the trees take years to reach a decent size. But, Matilda explained, a genetic engineer like her could remedy that defect, by using gene-splicing to create a tree that would grow two meters every month.

Matilda was right. After she got the genetic engineering right, Fast Trees became popular all over the country. People loved the idea that they could plant a tree in April and get a good shade tree by July or August.

Nat should have been happy with his clever wife and the financial bonanza she had produced. But there was only one problem. Matilda was middle-aged and plain-looking, and Nat had developed a big crush on a much younger and prettier woman named Vanessa who lived down the street. Slowly an evil idea began to grow in Nat's mind: that he could kill his wife, and be left with the family fortune to do anything he pleased, such as wooing the lovely Vanessa.

For weeks Nat thought about ways he could commit the crime of killing his wife. Then one day he came home and found his wife in the back yard planting a tree. 

“We've made so much money from Fast Trees, it's about time we had one in our own yard,” said Matilda. She had dug a large hole in which to plant the tree sapling. Next to the hole was a large pile of soil and the tree sapling. 

At this point a terrible thought entered Nat's mind. This is my golden opportunity, he thought to himself. Now that she's dug that hole, I'll just kill her with the shovel, and bury her in the hole.

BANG! Nat struck his wife's head with the shovel, and she fell to her knees. BANG! Nat hit his wife's head again with the shovel, and she fell to the ground, twitching. BANG! Nat hit his wife's head again with the shovel, and she died.

Nat then threw Matilda's body into the hole. He asked himself: what should I do with the Fast Tree sapling? He decided to throw that into the hole also. Then he filled up the hole, tossing all of the soil from the pile of soil into the hole. He then covered up the filled hole with a sprinkling of leaves. 

Nat then began to tell a story that his wife had ran away with another man. He began to spend some of the family fortune on fancy cars, gambling, and wild parties. Meanwhile, the Fast Tree planted in the back yard began to grow very quickly, just as genetically engineered Fast Trees always did.

One day Nat was having a wild party with several beautiful young women including Vanessa. There was loud music and much drinking. But suddenly the party was interrupted by a loud noise.

BANG! There was a sound of something rapping on the window. BANG! The loud sound was heard again. BANG! The third rapping sound caused Nat to wonder if this could be the police coming to investigate his wife's disappearance. Nat went to the window.

“Oh, it's only a branch rapping against the window,” said Nat. The branch was a branch of the Fast Tree, which in the two months since Matilda's murder had now grown to a height of four meters.

Nat felt a chill when he looked at the branch that was knocking on the window. The end of the branch had finger-like protruding twigs that made the branch resemble a human hand.

There was no further noise from the branch that day. The next day Nat was alone watching his holographic wall-screen. He was again disturbed by a rapping noise.

BANG! The tree branch knocked on the window. BANG! The loud sound was heard again. BANG! The third rapping sound caused Nat to notice that it had been three raps against the window, just like on the previous day.

There were no more knocks of the branch against the window. The next morning Nat had a troubling thought. He remembered he had killed his wife using three blows with a shovel. And each night the branch had rapped on the window, it had banged three times. Nat asked himself: was this just a coincidence?

Nat was troubled, and he tried to smother his worries with alcohol and partying. The next night he again entertained friends, including the young Vanessa. There was more loud music and laughing conversation. But then the sounds returned.

BANG! The tree branch knocked on the window. BANG! The loud sound was heard again. BANG! The third rapping sound caused Nat to lose his composure.

“Bang, bang, bang!” hollered Nat. “BANG, BANG, BANG! Have you noticed that the accursed tree branch always bangs the window three times? It's like the branch was trying to remind me of the three blows I struck to my wife's head!”

“What's that?” said Vanessa. “You told me your wife had left you, not that you hit her three times on the head. I'd better leave, and let you work this out in your own mind.”

Vanessa left, and drove immediately to the police. She told about what Nat had said. The next day the police arrived at Nat's house with a search warrant. Using one of the new portable X-ray scanners, they scanned the back yard, and quickly found the shape of a buried body. They dug up the Fast Tree that was two months old. They found that the roots of the tree had become completely entwined with the heart of a decaying corpse. It was the corpse of Nat's murdered wife Matilda.

Presented with the evidence, Nat confessed the murder. He was sentenced to life in prison.

After his imprisonment, there was debate about the strange case. Some said that the banging of the strange branch with a hand-like end must have been somehow caused by the spirit of Nat's wife Matilda, who may have haunted the tree entwined with her corpse. Others said it was all just a coincidence.

Which of these was right? The answer will never be known in this mortal life.

The Poor Design of Online Heart Risk Calculators

A few days ago the Washington Post published an article criticizing the reliability of online heart risk calculators. But the article failed to discuss the main reasons why such calculators are poorly designed. Let's look at some of the reasons why the average heart risk calculator is likely to do a poor job of alerting you if you have a relatively high risk of a heart attack over the next ten years.

Reason #1: The calculators ask for inputs on current cholesterol levels rather than asking about your lifetime eating habits.

All of about 8 or 9 online heart risk calculators I've looked at ask for your current total cholesterol level and the level of your HDL or “good” cholesterol. There are some big problems with doing that. The first is that a large fraction of all people don't remember what their latest HDL reading was. If you are like most people over 50, you probably remember whether your latest cholesterol reading was above 200, but don't remember what your HDL reading was. In such a case you will be unable to proceed when you come to a calculator such as the calculator here.

Another problem is that your latest cholesterol reading may not be a very good indicator of your current eating habits. Many people alter their eating habits in the weeks before taking a scheduled blood test, in hopes of getting a better cholesterol reading.

A third reason is that your heart attack risk depends relatively little on your current cholesterol level, and more on your lifetime eating habits. A heart attack can occur when plaque builds up in your arteries. The likelihood of that happening depends on your eating habits over the past few decades. Let's imagine two people, Ed and Sam, both age 60. Ed has been eating tons of red meat for four decades, but in the past year has reformed his eating habits, and brought his total cholesterol down to 200. Sam for the past 40 years has been eating little food high in bad cholesterol, and lots of food high in good cholesterol. But in the past year he's slipped a little, and his total cholesterol is now 220. Which has a higher chance of heart attack? It's Ed, not Sam, despite Ed's current lower cholesterol – because your lifetime eating habits determines how much plaque is in your arteries.

It would seem that rather than asking about your latest cholesterol reading (requiring an HDL number you probably don't know), our heart risk calculators should instead be asking about your lifetime eating habits.

Reason #2: None of the calculators has an input for resting heart rate.

There have been many scientific studies indicating that a person's resting heart rate has a large effect on a person's chance of having a heart attack or suffering sudden cardiac death. In the large Framingham heart study, the average resting heart rate for a male was 64 beats per minute. A much larger FitBit data set (derived from millions of users of FitBit devices) suggests that the average heart rate for male 60-year-olds in the US was about 62 beats per minute. But what if your resting heart rate is 70 beats per minutes or 80 beats per minute or 87 beats per minutes? According to numerous studies such as this one, your risk of heart failure or sudden cardiac death is much higher – perhaps as much as 300% higher for someone with a heart rate greater than 85 beats per minute.

Given the significance of heart rate, and the ease in which anyone can get their own resting heart rate by holding their wrist and using a clock, there would seem to be no excuse for not having a heart rate input slot on every online heart risk calculator. But how many such calculators have such a thing? None of them do.

Reason #3: Most of the calculators don't allow you to specify whether you have a family history of heart disease.

Most of the online risk calculators use what is called the ASCVD algorithm, and such calculators do not ask you whether you have any family history of heart disease. For example, the first calculator I get when I do a Google search for “heart risk calculator” is a calculator that does not ask me for whether anyone in my family had a heart attack.

But there is one online heart risk calculator that uses the “Reynolds risk” formula for computing heart risk, and that calculator does ask me “Did your mother or father have a heart attack before age 60?” When I choose “Yes,” my calculated 10-year heart attack or stroke risk jumps from 8% to 13%. So evidently whether your father or mother had a heart attack before 60 is a big factor that can affect your heart risk by as much as 40%. So why do the vast majority of online heart risk calculators not allow you to specify whether your mother or father had a heart attack before the age of 60?

Reason #4: None of the calculators allow you to specify whether you have a diagonal earlobe crease.

A diagonal earlobe crease is a line that some people have going across their earlobes. It looks like this:

Quite a few scientific studies have shown that if you have a diagonal earlobe crease on both ears (called a “bilateral” earlobe crease), the chance of you having cardiovascular disease is much higher. For example, this 1982 study was based on exact measurements of the artery health of 340 people, using coronary arteriography. The study found that having a diagonal earlobe crease has a positive predictive value of 91% for coronary artery disease, meaning if you have the diagonal earlobe crease you are 91% likely to have coronary artery disease. A similar 2004 study of 415 people (also using exact artery measurements though angiography) found that having the diagonal earlobe crease had a positive predictive value of 89% for coronary artery disease.

Clearly all of our heart attack risk calculators should have an input allowing you to specify whether you have an earlobe crease. But none of these calculators has such an input.

Reason #5: None of the calculators has an input asking about your exercise levels.

How much a person exercises can affect his risk of having a heart attack. It will come as little surprise that not exercising at all will increase your risk of a heart attack. But what is surprising is that a major study found that those who exercise very heavily may have a much higher risk of heart attack. Such is the finding of the very large CARDIA study. The Science Daily site reports this finding with the headline, “Physically active white men at high risk for plaque buildup in arteries.” The site states, “White men who exercise at high levels are 86 percent more likely than people who exercise at low levels to experience a buildup of plaque in the heart arteries by middle age, a new study suggests.”

Clearly, a decent heart attack risk calculator should have an input for how much you exercise. But none of the online calculators has such a thing.

Reason #6: None of the calculators has an input asking about how much time you spend sitting. 

It is sometimes said, "Sitting is the new smoking," because too much sitting can cause an increased chance of heart attack.  A 2015 meta-analysis on the association between heart risk and sitting found an association, but a pretty modest one, with a hazard ratio of 1.143, meaning lots of sitting might cause a 14% higher chance of a heart attack.   But a 2012 meta-analysis found a much larger risk, finding that those who sit the most can have "a 147% increase in the RR [relative risk] of cardiovascular events." Clearly a question on how long you spend sitting each day should be included in a heart risk calculator. None of them currently has such a thing. 

Reason #7: None of the calculators has an input asking about how much time you spend standing at work. 

Given the information just discussed, you will be surprised to read the following quotes from a scientist who summarizes a large study done by he and his colleagues:

We found that people who primarily stand on the job are twice as likely to develop heart disease as people who primarily sit....In fact, the incidence of heart disease among those respondents who stood a lot at work (6.6 per cent) was similar to the incidence of heart disease among workers who smoked on a daily basis (5.8 per cent) or those who were obese (6.9 per cent). 

What a decent heart attack risk calculator would look like

Based on all these considerations, I can show what a good heart attack risk calculator would look like. It would look like the page below, a page looking very different from all existing heart attack risk calculators. Unfortunately I can give you no URL for a page that implements such a design. I hope someone with expertise in this field will one day implement such a calculator. 

The Two Huge Asymmetry Mysteries Scientists Can't Solve

Among the many mysteries scientists cannot solve, two of them involve gigantic asymmetries that scientists cannot explain. The first such asymmetry is what is called the matter/antimatter asymmetry. Scientists believe that when two very high-energy photons collide, they produce equal amounts of matter and antimatter, and that when matter collides with antimatter, it is converted into high-energy photons. Such a belief is based on what scientists have observed in particle accelerators such as the Large Hadron Collider, where particles are accelerated to near the speed of light before they collide with each other. But such conclusions about matter, antimatter and photons leads to a great mystery as to why there is any matter at all in the universe.

Let us imagine the early minutes of the Big Bang about 13 billion years ago, when the density of the universe was incredibly great. At that time the universe should have consisted of energy, matter and antimatter. The energy should have been in the form of very high energy photons that were frequently colliding with each other. All such collisions should have produced equal amounts of matter and antimatter. So the amount of antimatter should have been exactly the same as the amount of matter. As a CERN page on this topic says, "The Big Bang should have created equal amounts of matter and antimatter in the early universe." But whenever a matter particle touched an antimatter particle, both would have been converted into photons. The eventual result should have been a universe consisting either of nothing but photons, or some matter but an equal amount of antimatter. But only trace amounts of antimatter are observed in the universe.

It would be incredibly inconvenient if matter and antimatter were equally distributed. So much energy is released when matter makes contact with antimatter that if there were trace amounts of antimatter lying about, you'd have “oops, someone blew up Europe because he stepped on a tiny piece of antimatter” situations all over the place.

The asymmetry of matter and antimatter (the fact that matter and antimatter do not exist in equal amounts) reminds us of the fact that the Big Bang theory is not quite a successful theory, in the sense of making only predictions that match reality. We read in the popular press triumphalist talk like the statement below by cosmologist Ethan Siegel:

This picture is part of what’s known as the hot Big Bang, and it makes a whole slew of predictions. Each one of these predictions, like a uniformly expanding Universe whose expansion rate was faster in the past, a solid prediction for the relative abundances of the light elements hydrogen, helium-4, deuterium, helium-3 and lithium, and most famously, the structure and properties of galaxy clusters and filaments on the largest scales, and the existence of the leftover glow from the Big Bang — the cosmic microwave background — has been borne out over time.

Siegel here fails to mention that the Big Bang theory predicts a universe with either equal amounts of matter and antimatter, or all energy and no matter (which is what would result from all the matter combining with antimatter). That is a gigantic prediction of the theory that does not match reality. We don't patch up this problem by adding the “cosmic inflation” speculation to the Big Bang theory, as that also predicts a universe with either no matter or equal amounts of matter and antimatter. So rather than engaging in such triumphalist talk, our cosmologists should be saying, “There must have been something far more going on at the beginning than we understand.”

Every several years we hear about some type of result (typically preliminary) which we are told may hold an answer to the mystery of matter/antimatter asymmetry. But such results don't hold up over time. The latest report of a promising preliminary result came in 2017, but by 2018 news stories were throwing cold water on such results, saying they did nothing to explain the mystery of matter/antimatter asymmetry.

There's another gigantic mystery involving asymmetry that scientists don't understand: the mystery of homochirality. Chemicals such as amino acids and sugars can be either left-handed or right handed. A left handed amino acid looks like a mirror image of the right-handed amino acid. Homochirality is the fact that in living things essentially all amino acids are left-handed, and all sugars are right-handed. But when such things are synthesized in a laboratory, or experimentally produced in experiments such as the Miller-Urey experiment, you see equal amounts of left-handed and right-handed amino acids or equal amounts of left-handed and right-handed sugars.

A left-handed amino acid and its right-handed counterpart

Based on the fact that it is just as easy for left-handed amino acids to form in the laboratory as right-handed amino acids, and just as easy for left-handed sugars to form in the laboratory as right-handed sugars, we would expect for there to be a symmetry in the handedness of amino acids, with an equal amount of left-handed and right-handed amino acids. We would also would expect a symmetry in the handedness of sugars, with equal amounts of left-handed sugars and right-handed sugars. But what we see is an asymmetry, with living things having only left-handed amino acids and right-handed sugars.

I can give an analogy for why homochirality is such a mystery. Let us imagine a stack of cards. On one side is a particular word.

And on the other side is the mirror image of that word.

Now, let us imagine someone tosses this stack of cards into the air, and the cards randomly arrange into a long, elaborate instruction. Let us also imagine that all of the cards show only one side: the side with the intelligible word, and not the side with the mirror image of that word.

We would have two great problems in explaining such a thing. The first would be that this elaborate set of instructions had formed randomly. The second problem would be explaining how all the cards had landed in a way so that all of the regular words had appeared, without any of the mirror image words appearing. A similar problem comes with explaining the origin of life. We have to explain not merely the “organization explosion” in which huge amounts of functional information appeared, but also the fact of all the amino acids being left-handed and all the sugars being right-handed. The fact of this homochirality greatly compounds the problem of explaining the origin of life.

There was in the news recently a goofy news story on this topic, which stated the following:

Homochirality, or one-handedness, plays a key role in cellular chemical reactions, and all living organisms (that we know of) contain the ‘left-handed’ molecules. Scientists aren’t sure why this is, but some believe the answer may have something to do with the molecules’ cosmic origin. In 2016, researchers found propylene oxide, a chiral molecule, in Sagittarius B2, which is a massive molecular gas cloud roughly 25,000 light years from Earth, near the center of our Milky Way Galaxy. The findings suggest that the chiral molecules necessary for life may have come from space, particularly from star-forming regions.

This is hardly helpful in explaining the mystery of homochirality. What we want to know is why sugars and amino acids display homochirality, and the fact of a “chiral molecule” of the biologically irrelevant propylene oxide modecule does nothing to explain that. The existence of a chiral molecule does not explain homochirality, just as the existence of a two-sided penny does not explain 300 consecutive coin flips that were all heads rather than tails. The problem isn't the existence of chiral molecules (molecules that can be left-handed or right-handed). The problem is why in living things we see only left-handedness in amino acids and right-handedness in sugars.

A much better article about homochirality is “The Origin of Homochirality” in the Chemistry World magazine. The article points out why homochirality is necessary for living things, saying, “No homochirality, no life.” The article says that according to a London chemist, “understanding homochirality is still completely unresolved.”

It would seem that once we consider homochirality, we need three miracles for life to appear from non-life. The first miracle is just for you to get all of the genetic information needed for life to begin, at least 160,000 DNA base pairs arranged in just the right way (with also the proteins that correspond to such a genome). The second miracle is for you to have homochirality, so that all of the amino acids have the same handedness, and all of the sugars have the same handedness. The third miracle is for the genetic code to originate, a complex symbolic system of representations in which particular combinations of nucleotides represent particular amino acids. Similarly, it would be a triple miracle if your 2-year-old in America were to start speed typing well-written how-to books in French. The first miracle would be that he could understand enough to write how-to-books, the second miracle would be that he could write in French, and the third miracle would be that he could do speed typing on a keyboard.