In Neuroscience and Astrobiology, What Was Not Seen Matters As Much As What Was Seen

Another day, another not-really-true story in our "science news" feeds. The story is one appearing in the Daily Mail, claiming that "A gas 'uniquely associated with life' when found on Earth has been discovered in the atmosphere of K2-18 b, which is known as a 'super Earth' because it is bigger than our planet but smaller than Neptune." The actual scientific paper (which you can read here) makes no such claim of a discovery about such a gas (dimethyl sulfide), merely stating "The spectrum also suggests potential signs of dimethyl sulfide (DMS)."  The text of the paper says, "We find marginal evidence for DMS," which is sure not a claim of a discovery.

Dimethyl sulfide is not a very complex molecule, having a formula of six hydrogen atoms, two carbon atoms and a sulfur atom. On Earth dimethyl sulfide is produced only by biological processes, but on some extraterrestrial planet with a greatly different chemistry, it might be produced by nonbiological processes.  There's a big reason why we should not regard the "marginal evidence" for dimethyl sulfide as any indicator of life on K2-18 b: the scientific paper reports that the search for chemicals on the planet produced no sign of water. We read this:

"We do not find significant contributions due to H2O or NH3, but find 95% upper limits of -3.21 for log(XH2O) and -4.46 for log(XNH3 ) in the no-offset case. These upper limits are also consistent with those from the other retrieval cases, as shown in Table 2. The non-detections of both molecules are important considering their strong spectral features and detectability expected in the 0.9- 5.2 µm range (Madhusudhan et al. 2021; Constantinou & Madhusudhan 2022). The non-detection of H2O is at odds with its previous inference using the HST WFC3 spectrum in the 1.1-1.7 µm range (Tsiaras et al. 2019; Benneke et al. 2019a; Madhusudhan et al. 2020)."

It is generally agreed that water is absolutely necessary for any form of life of life to exist. The non-presence of water at K2-18 b is a reason for thinking that life does not exist there. The story on www.yahoo.com very much misinforms us by stating this:

"The ability of a planet to support life depends on its temperature, the presence of carbon and probably liquid water. Observations from JWST seem to suggest that that K2-18b ticks all those boxes."

No, the scientific paper says that water was not detected on  K2-18b, even though a sensitive test was made that should have detected traces as low as 1 part in a billion. 

What we have here is a "what was not found tells us very much" case a little like what happened with the 1976 Viking lander on Mars. The lander had multiple tests to try to gather evidence for life on Mars. In a result that might have been caused either by a deficiency of the experimental equipment or by some unusual chemistry producing an effect mimicking what microbes would have produced, a test called the labeled release experiment seemed to indicate the existence of life. But other instruments on the lander failed to find any evidence of organic matter. Organic matter (matter rich in carbon) is as necessary for living things as water.  

In this case scientists had to pay equal attention to what was observed and what was not observed. The non-observation of organic molecules seemed to say in a loud voice that Mars (or at least the part of Mars tested) was lifeless. Other missions found the tiniest traces of some biologically irrelevant organic molecules, but only in negligible amounts. 

Table 1 of the 2023 paper here lists all of the missions that have searched for organic compounds on Mars, and exactly what they found. We find no mention of any of the molecular components of living things. There's no mention of amino acids (the components used to build proteins), and no mention of any of the chemicals used to make RNA or DNA. The organic compounds listed as being found by the Perseverance mission are merely benzene and naphthalene, neither of which is a component of living things. The largest abundance mentioned is only 300 parts per billion, about 1 part in 3 million. 

The non-observation of amino acids is an extremely important clue telling us that Mars is almost certainly lifeless, and suggesting that any attempt to return Mars rocks or soil to Earth will almost certainly not reveal either life or traces of previous life.  Based on the non-observation of amino acids  on Mars, scientists should have told NASA to cancel its plan to retrieve soil and rock samples from Mars.  But scientists have failed to do that. It's a case of scientists paying insufficient attention to what was not found. 

Something similar occurs in the world of neuroscience. Neuroscientists pay endless attention to tiny little details observed in brains. But they senselessly seem to pay almost no attention to what has not been found in brains. What has not been found in brains tells us just as much (and possibly more) as anything that has been found in brains. 

Billions have been spent on studying brains. Brain tissue has been examined with instruments of ever-increasing power. Below is an interesting graph from a web page of the National Institute of Health. You can see the graph by using the link here. The original graph had a hard-to-read use of a yellow line, so I have changed the colors, and added a phrase identifying which line represents neuroscience funding. 

We see from this graph that there was a great spike of funding for neuroscience, which reached its peak around 2012, when the NIH was paying nearly 500 million dollars a year for neuroscience research. In that year funding for neuroscience exceeded funding for things such as immunology and health sciences.  But despite all of this lavish funding, there are some very important things that neuroscientists have never found:

Not found #1: any trace of learned human knowledge or experience in a piece of microscopically examined brain tissue.  

Within cells below the neck, there is stored information in DNA using a system of representations called the genetic code. Scientists were able to discover such a system in the middle of the 20th century, and were able to start recovering information stored using such a system, which was all low-level chemical information such as which amino acids make up particular proteins. If the human brain stored memories, there would be brain areas storing memories that could be studied microscopically to find what a person had learned or experienced. Scientists would then be able to find out some of the things someone (living or dead) had learned or experienced by studying his brain, and would be able to say things such as "I see he studied French" or "I see this dead man once lived in a blue house." No such memories have ever been discovered by microscopically examining brain tissue, even though scientists today have vastly more powerful microscopes than they had in the 1950's.  No one has ever been able to find any trace of what a person learned or experienced by studying such a person's brain tissue through a microscope or any other device. 

Not found #2: any encoding system by which human experiences and learned information could be converted into neural states or synapse states.

If a human brain stored memories, there would need to be some system or systems of encoding by which information you learned in school and experiences you had were stored as brain states.  Because  of the vast variety of things that people can remember (some experiential, some visual, some auditory, some textual, and some musical), it seems there would have to be not one simple system of encoding (like the genetic code) but many very complex systems of encoding allowing all the different things people can experience and learn to be stored as neural states. No such system of encoding can be found anywhere in the brain.  Besides failing to even microscopically find the words "cat" or "dog" or any other word stored in brain tissue, scientists don't even have any credible theory of how text or images or life experiences or concepts could be stored as neural states or synapse states. Given that the genetic code was discovered in the 1950's, and that the "footprints" of some code for converting human learned knowledge and human experience into stored memories would have to be much larger than such a genetic code, I estimate that if such a "neural code" for storing memories existed, it would have been discovered in the 1950's. 

Not found #3: any token repetition in the brain other than the nucleotide base pair tokens capable of representing only low-level chemical information such as sequences of amino acids.

Even when there is an encoding system that has not yet been deciphered or figured out, there will be indications that such an encoding system exists. The indications are repeated tokens. Before Europeans were able to figure out how hieroglyphics worked, they knew that hieroglyphics used some type of encoding system, because they could see how frequently there was a repetition of individual tokens or symbols. Not counting the genetic information stored in neurons and many other types of cells, where we do see an enormous amount of token repetition, there is no sign of any token repetition in the brain. This is a clear sign that the brain does not use any system of encoding to store human memories.  And if there is no such system of encoding, we should not think that brains store memories; for some system of encoding would be required to convert human experiences and human learned knowledge into brain states. 

Not found #4: any physical characteristics in the brain that might enable the kind of instant recall of correct answers that humans show when asked a question. 

Human recall typically occurs instantly. If you ask me "where was Abraham Lincoln shot," I do not say, "Hold on, let me scan through my memories, and after a while I'll tell you." Instead, the instant you have finished answering the question, I answer, "Ford's Theater in Washington, D.C."  If such a thing were to occur by brain activity, the brain would need to have aspects that can explain instant recall.

 Humans manufacture objects that allow instant retrieval of information, things such as books with numbered pages and indexes, encyclopedias with alphabetically sorted entries, and computers that can instantly retrieve information.  We know from such things that humans make what are the kind of things that enable instant retrieval using material objects. They are things such as sorting, addressing and indexing. In a book, page numbers are the addresses, and the indexes are sorted and make use of such page numbers. Computers that connect to relational databases or web pages (as all computers do these days) also use sorting, indexing and addressing. Every web page has an address, and relational databases use sorting, indexing and addressing to allow instant recall.  But in the brain there is no sign whatsoever of any sorting, indexing or addressing.  Neither neurons nor synapses have any addresses, and given the strongly entangled physical structure of neurons, it is impossible for brains to sort their neurons. No sign of any indexing can be found in the brain, and since indexes require sorting and addressing (things not found in the brain), there cannot be any indexing in the brain.  The lack of any addressing, indexing and sorting in the brain is a strong sign that instant recall of correct answers cannot be any activity of the brain. Scientists have no credible tale to tell of how the instant recall of correct answers could occur by brain activity. 

There are quite a few other examples of important things not found in the brain. Collectively such important neural shortfalls suggest that the brain cannot be the storage place of our memories and cannot be the source of our minds. But alas the members of the neuroscientist belief community fail to pay attention to what has not been found by studying brains. They fail to recognize the very important principle that what is not observed can tell you as much (and sometimes more) as what was observed.

Postscript: Since today's post is partially about astrobiology, I should comment on the story in today's Daily Mail with this headline: "Alien' bodies with three-fingered hands, 'unknown DNA and eggs inside' are presented by UFO expert at Mexican congress - with the 'non-humans' found in Peru said to be 1,000 years old."  A few random thoughts:

(1) The objects displayed are about the size of a human baby, and the heads look about one quarter the size of a human head.  A materialist might wonder: how could such tiny-brain creatures be smart enough to master interstellar travel?

(2) From outward appearances, the objects displayed look more like sculptures than corpses. We see no signs of clothing, and may ask: why would extraterrestrials be walking around naked on Earth?

(3) We have a caption claiming "the corpses, recovered from a mine in Cusco, Peru, had a genetic composition 30% removed from that of human beings."  We would expect any extraterrestrial life to have a genetic composition 100% different from humans.  Earthly life uses a system of representations (the genetic code, shown above) that is an arbitrary scheme of representations.  We would never expect life arising on some other planet to have even 20% genetic similarity with humans.  A "genetic composition 30% removed from that of human beings" would suggest some undiscovered earthly species (along the lines of Bigfoot) rather than a species coming from some other planet. 

Wired magazine has an article claiming the Peru objects are a mixture of animal and human material, held together with glue.  On September 14, 2023 NASA  released its much-anticipated report on UFOs and Unidentified Anomalous Phenomena. It's a mere "going through the motions" affair that reads like about as lazy an effort as could have appeared, as if written by people with no interest in this topic, unwilling to seriously study the topic, who just "phoned it in." 

Almost all of the press coverage on the K2-18 b study discussed above has been of very low quality. Almost all press reports claimed incorrectly that a discovery of dimethyl sulfide had been made, which was not a claim made by the paper. The paper merely claimed "marginal evidence" for dimethyl sulfide. The press articles almost all fail to tell us that no water was detected despite a very sensitive search (something that removes any biological relevance for K2-18 b); and quite a few of them mislead us by trying to insinuate that K2-18 b has water.  Some of the headlines in mainstream publications told the big fat lie that "signs of life" had been found in space. Let this be a lesson: the information presented by the science press very often consists of falsehoods or cherry-picked facts and spin designed to be clickbait or to get you to believe as the author wishes; and it is very common for the science press to fail to inform you of the most important relevant facts and observations relating to some topic being written about.