Many Physicists Prefer Design Explanation of Cosmic Fine-Tuning

"The cosmological constant must be tuned to 120 decimal places and there are also many mysterious ‘coincidences’ involving the physical constants that appear to be necessary for life, or any form of information processing, to exist....Fred Hoyle first pointed out, the beryllium would decay before interacting with another alpha particle were it not for the existence of a remarkably finely-tuned resonance in this interaction. Heinz Oberhummer has studied this resonance in detail and showed how the amount of oxygen and carbon produced in red giant stars varies with the strength and range of the nucleon interactions. His work indicates that these must be tuned to at least 0.5% if one is to produce both these elements to the extent required for life."  -- Physicists B.J. Carr and M.J. Rees, "Fine-Tuning in Living Systems." 

 Prior to Darwin, William Paley made a famous analogy in his book Natural Theology, the analogy of a someone walking along a beach and finding a watch. Paley argued that it would be unreasonable for any such person to deny that such a thing (with so purposeful an arrangement of so many parts) was a product of design; and that it is just as unreasonable to deny that the purposeful arrangement of parts we see so abundantly in biological organisms is the product of design. The untrue legend arose that Darwin answered Paley's argument; but he did not. Darwin never mentioned Paley's famous analogy in any of his chief writings. Darwin never credibly explained how some fine-tuned arrangement of very many parts to meet a particular functional end could be naturally achieved. Darwin paid almost no attention to the huge fine-tuned complexity and component interdependence in organisms. 

In the twentieth century, the evidence for what looks like purposeful design in organisms increased enormously, as scientists discovered the enormous organization and component interdependence of hundreds of types of human cells and thousands of types of protein molecules, very high levels of functional complexity Darwin knew nothing about. In the late twentieth century, it began to become clear that there was a second gigantic basis for believing in design in nature: the fine-tuning of the universe's fundamental constants and laws. It turns out that the universe must be very specially arranged for there to be any possibility of there being creatures such as human beings and civilizations such as our civilization. The table below helps to show some of the requirements. The color coding helps to show how the same things recur as requirements for multiple things. 

In 2024 a poll was taken at the Black Holes Inside and Out conference in Copenhagen. 85 physicist attendees filled out a survey, with the results described in the "Copenhagen Survey on Black Holes and Fundamental Physics" paper here. One of the questions was framed as follows: "In your opinion, what explains the values of physical constants of nature and the claimed anthropic coincidences?"  The wording of the questioning was biased, with the phrase "anthropic coincidences" tending to suggest a "just chance" explanation. Despite the wording, a small but significant fraction of the physicist respondents expressed support for an "intelligent designer" answer. 

The results were these:

About 3% of the physicist respondents preferred an explanation of "an intelligent designer." The most popular explanation was the non-explanation of "brute facts." Someone appealing to brute facts is someone basically saying, "There is no explanation."

The authors of this survey have since done a more recent survey, asking some of the same questions, but polling a much larger group of physicists. They give their results in the paper "Big Mysteries Survey: Physicists’ Views on Cosmology, Black Holes, Quantum Mechanics, and Quantum Gravity," which you can read here. The authors of the paper start out by stating this:

"In the summer of 2024, a survey was conducted at the Black Hole Inside Out Conference in Copenhagen to assess physicists’ views on a range of ongoing controversies. Eighty-five scientists responded. One year later, the authors collaborated with the American Physical Society’s Physics Magazine on a substantially larger follow-up survey, which polled 1,675 participants from the magazine’s readership and the members of the American Physical Society. The Physics Magazine survey therefore provides a broader view of attitudes within the physics community and allows comparisons with the more focused conference-based Copenhagen sample."

Figure 1 of the paper tells us that 70% of the respondents identified themselves as researchers, with only 21% identifying themselves as "a science enthusiast" or "other."

Question 6 of the survey was framed as below

Question 6: Anthropic Coincidences

Question. The values for nature’s physical constants—from the strength of nuclear forces to the mass of the electron—are not determined by current theories, It has been suggested that if these values had been slightly different, the universe would likely not have formed complex structures and—eventually—life. This idea has led some to call for other physical or even metaphysical hypotheses to explain the apparent 'coincidence' that these constants are tuned to life-permitting values. Others have however questioned if such arguments are on sound footing. In your opinion what explains the values of physical constants and these so-called anthropic coincidences?

Like the corresponding question in the previous survey, this question is biased. Its heading of "Anthropic Coincidences" rather seems designed to suggest in respondents the idea of mere chance or coincidence being involved. Nonetheless, a substantial fraction (9%) of the respondents selected "explained by an intelligent designer" as their answer to the question posed above. The responses are given below:

I may note that the paper documenting this poll makes no claim that it was a secret ballot poll, and makes no mention that the respondents were guaranteed that their responses would be kept confidential. In polls such as this, we can assume that any controversial answer would get a much higher response under circumstances in which the secrecy of a person's response would be guaranteed. 

None of the answers other than "explained by an intelligent designer" have high credibility. Specifically: 

• The first answer in the list above is the mangled claim that "the values of the constants are set by a principle (such as the 'naturalness' principle forbidding a theory to have independent, fine-tuned parameters)." The offered example makes no sense. The issue is why our universe has fine-tuned constants. You don't explain that by appealing to some principle involving theories. 
• The most popular answer ("they are brute facts that need no further explanation") is just an "I have no explanation" answer. 
• The "explained by anthropic selection in a multiverse" answer is witless. There is no evidence and can never be any evidence for any such thing as a "multiverse," some vast collection of other universes. The only universe we can ever observe is our own universe. There is no credibility in the idea of "anthropic selection." If a multiverse existed, it would not do any such thing as "anthropic selection" in the sense of selecting creatures like us, living in civilizations and enjoying long lives and having the ability to speak languages. It would be true that only observers could observe, but it would be almost infinitely more likely that chance would produce low-intelligence observers with very short lifespans not enjoying all of the conveniences we enjoy such as a pleasant planet, long lives, and metal abundances allowing long-lasting civilizations. And a multiverse would do nothing to explain why our universe was so lucky (as opposed to some universe). For a full discussion of the fallacies in trying to evoke a multiverse to explain our universe's fine-tuned features, see my posts here and here. 
• The "explained by a Darwinian process occurring in the cosmos (e.g. baby universes inside black holes)" answer is a reference to Lee Smolin's very silly, groundless and extremely speculative theory he called "cosmological natural selection." In a 2004 paper (page 38) Smolin said that the theory made a prediction, the prediction that "the upper mass limit of neutron stars is less than 1.6 solar masses." This prediction failed. The most massive known neutron star is PSR J0952-0607, which has a mass of approximately 2.35 times of the mass of the sun. 

The word "beachhead" is a military term referring to an initial position on an enemy-dominated territory, a position serving as a foothold for further expansion. We can describe the situation in regard to belief in intelligent design among physicists like this: the idea of an intelligent designer behind cosmic fine-tuning is an idea that now has a foothold or beachhead among physicists. We should not be surprised at all if this foothold is followed by a much greater expansion. The beachhead may turn into a breakout, maybe even something like the breakout of Patron's Third Army in August, 1940, arising from the beachhead at Normandy.  Today's 9% physicist belief in intelligent design could easily expand to be 20% or 30% within a few decades. 

A similar poll questions was answered by academic philosophers. As discussed in my post here, in that poll, more philosophers said they believed in a "design" explanation for "cosmological fine-tuning" than the percentage believing in "multiverse" as an explanation. This was despite the fact that academic departments of philosophy have long been environments in which atheistic thinking is predominant. 

The idea of pondering only the fine-tuned physics of our universe when considering the explanation for such fine-tuning is an approach that is defective. The more sensible approach is to consider the collective weight of all the cases of fine-tuning that we observe in nature, which include things that are tangible (such as human bodies) and things that are intangible (such as fundamental constants of physics). 

We now have more than 50 years of work in modern physics establishing how the habitability of our universe depends on just-right characteristics of numerous laws and fundamental constants of the universe. I document in my post here some of the physics papers that documented this reality in the 1970's. Work of this type continues. A 2023 paper by a physicist states the following:

"The values of some fundamental physical constants are considered to be finely tuned and balanced to give our observable world. Examples include finely tuned balance between quark masses needed to produce protons and neutrons ...and production of heavy nuclei in stars, which depends on the finely tuned balance between the fine structure constant ...and the ratio of the proton mass ..and electron mass...These and other examples suggest a narrow 'habitable zone' in parameter space...where essential biochemical elements can form... For this reason, fundamental constants are referred to as 'biofriendly' or 'biophilic' ....We need to tune the same fundamental constants setting α and β (ℏ, e, c, me, mp) that, importantly, involves tuning, which is additional and different to tuning involved in fixing α and β....We can conjecture that multiple independent tunings were involved. This includes tuning fundamental constants to produce heavy nuclei and additional tunings needed for other observed sustainable structures to emerge." -- Kostya Trachenko, "Constraints on fundamental physical constants from bio-friendly viscosity and diffusion" (link).

Problems With the Vickers Paper Polling Scientists About Extraterrestrial Life

 In 2025 there appeared the paper "Surveys of the scientific community on the existence of extraterrestrial life" by Vickers et. al. The paper had a survey on the topic of whether scientists believe in extraterrestrial life. Below are the results, from questions in which scientists were asked whether they think that on other planets there is life, complex life, or intelligent life. 

There are several problems with the paper and its survey, which I will now discuss.

Problem #1: A Voluntary Response Email Survey 

The survey worked this way: scientists were sent emails asking them to reply to the survey, and 44% of the scientists replied by answering the survey.  But it is known that surveys of this type tend to be unreliable measurements of opinion, particularly when they are about some controversial topic. The problem is that there may be a much higher tendency for people who believe in some controversial theory to respond to a survey that asks only about their belief in that theory, rather than ignore such a survey. 

For example, imagine you send a survey to scientists that is only on the topic of controversial Theory X, a theory which most scientists scorn or have no knowledge of. It could be that 80% of the scientists getting this email decide to ignore it, thinking to themselves something like this: "Theory X? To hell with that." But it might be very different for some small minority of scientists who believe in Theory X. After getting the email, they may recognize the survey as an opportunity to improve the status of Theory X in the scientific community; and they may therefore be much more likely to respond. 

I remember a time more than 40 years ago when I worked two full-time jobs for a period of months. My second full-time job was a temporary job working for the US Census Bureau in Boston. The US government wanted to find out what percentage of the population used the fishing and wildlife services supported by the US government.  Workers like me were given stacks of survey forms, each of which had the name of a randomly selected US citizen. My job was to call up such people, and insist that they answer the survey's questions over the phone, questions asking about how often they used the government-supported fishing and wildlife facilities. I would have to keep calling back later if someone claimed to be too busy to answer when I called.  I would very frequently get responses like this from annoyed people:

"Why are you bothering to ask me about such things? I have never gone fishing in my life, nor have I ever gone hunting. So the government shouldn't be asking me about such things!"

I had to explain to such people the concept of a survey of random people: that the only scientifically valid way to find out what percentage of people used the government's fishing and wildlife facilities was to ask randomly selected people about this topic, to keep asking until all of them answered the questions, and to be just as interested in getting "no" answers as "yes" answers.  The US Census Bureau knew how to do a scientifically valid survey. The people at that bureau knew that it never would have been valid to just advertise some survey about fishing and wildlife, and to record what percentage of people choosing to do the survey said that they used fishing and wildlife facilities.  If you did the survey that way, it might have been that most of the participants would have been those who loved to do fishing and hunting.  The survey might then have given very misleading results perhaps suggesting that most people in the US use the government's fishing and wildlife facilities, when in fact only a small minority of the population used such facilities.  

Too bad Vickers et. al. did not seem to have the same knowledge of the proper way to determine what percentages of scientists think a particular thing. You cannot find out what percentage of a scientist community believes in a theory by sending them a voluntary survey on only that theory, one that will tend to get more replies from those who believe in that theory.  For example, if you send physicists a survey about their belief in the controversial theory called string theory, there will tend to be a much higher response rate from people believing in string theory than those not believing in it. 

One way to reduce the problem mentioned above is to do a voluntary email survey asking about many different things, such as a survey asking 50 diverse questions. With such a survey there will not tend to be an effect in which believers in some controversial theory are much more likely to respond. 

Problem #2: A Slanting in the Questions

Professional pollsters know that the way that a survey question is asked can have a very great influence on what kind of response people give. For example, here are two questions about gun control you could ask people in the USA:

Question 1: Do you think people should give up their right to bear arms given them by the Second Amendment of the US Constitution?

Question 2: Do you support gun control to reduce all these terrible mass shootings that keep happening?

Question 1 is a question about gun control, one slanted to produce a "no" answer. Question 2 is also a question about gun control, but it is  slanted to produce a "yes" answer.

Now, what are the questions in the Vickers survey? The paper lists these survey questions:

(Statement S1 – ‘Life’): It is likely that extraterrestrial life (of at least a basic kind) exists somewhere in the universe.

(Statement S2 – ‘Complex Life’): It is likely that extraterrestrial organisms significantly larger and more complex than bacteria exist somewhere in the universe.

(Statement S3 – ‘Intelligent Life’): It is likely that extraterrestrial organisms with advanced cognitive abilities comparable to or superior to those of humans exist somewhere in the universe."

These set of questions are a terrible way to survey people about extraterrestrial life. The questions have a very strong bias, because they doubly-suggest the idea that the least complex extraterrestrial life  would be simple. Humans know of no type of life that is simple. Even one-celled bacteria are very complex organisms that require hundreds of types of protein molecules, each its own complex invention requiring a very special sequence of hundreds of very specially arranged amino acids. 

The first way in which the survey questions above slants things and introduces bias is by using the phrase "of at least a basic kind" in the line referring to Statement S1. The second way in which the survey questions above slants things and introduces bias is by using the phrase "complex life" in referring to Statement S2. This indirectly suggests that what is being talked about in Statement S1 is life that is not complex. But all known life is very complex. So we have a severely slanted set of questions in which subjects are being asked to whether they agree that life "of at least a basic kind" exist, with the very misleading insinuation that such life could exist without being complex. Using such phraseology is introducing severe bias, as if the scientists running the survey were trying to gin up a response as high as possible to the first question. 

Then there is the fact that the survey suggests a particular opinion rather than asking a neutral question. Instead of being asked neutral questions asking things like "is it likely or not likely that..." we have questions stating a particular belief and asking whether respondents agree. It is well-known by pollsters that questions asked that way tend to produce a higher agreement with the stated belief.  For example, if you have a survey stating "marijuana use is safe" and asking whether people agree with that statement, you will get a higher level of agreement than if you ask "do you agree or disagree that marijuana use is safe?"

What would an objective, well-designed survey have looked like? It might have neutral questions like this:

Question 1: What do you think about the chances that there is  microscopic life on some other planet? 

Answer 1: Likely

Answer 2: Unlikely

Answer 3: I don't know/no opinion

Question 2: What do you think about the chances that there is  visible multicellular life on some other planet, such as organisms with organs? 

Answer 1: Likely

Answer 2: Unlikely

Answer 3: I don't know/no opinion

Question 3: What do you think about the chances that there is  intelligent life on some other planet, life as intelligent as humans or more intelligent?

Answer 1: Likely

Answer 2: Unlikely

Answer 3: I don't know/no opinion

Problem #3: No secret ballot

As a general rule, we should pay little attention to any survey in which scientists are asked about whether they believe in something that allegedly most scientists believe in, whenever the survey is not a secret ballot poll. The reason is that when a poll is not a secret ballot survey, scientists may answer in some way that they think they are supposed to answer, fearing that they may get in trouble if they do not go along with the majority. 

We have no evidence that the survey in the paper "Surveys of the scientific community on the existence of extraterrestrial life" is a secret ballot survey. In this case the lack of a secret ballot is relatively minor, because there did not exist a common idea that scientists were expected to think one thing or another about whether extraterrestrial life exists. 

Problem #4: Describing the results with the word "consensus"

In my post "So Much Misleading Talk Occurs in Claims of a Scientific Consensus," I discuss the word games that scientists play when they use the notoriously slippery, problematic and ambiguous word "consensus."  The problem is that "consensus" is a word with a double meaning. The Merriam-Webster dictionary gives us two definitions of "consensus" that disagree with each other. The first definition is "general agreement; unanimity." The second definition is "the judgment arrived at by most of those concerned." The first definition specifies 100%, and the second definition merely means 51% or more. 

Scientists very frequently exploit this ambiguity in a misleading way, just as they very frequently exploit ambiguity in the word "evolution" (another term with different meanings). Scientists may brag about a "consensus" on some topic when there is no evidence that even 90% of scientists agree on the topic.  They thereby are trying to create the impression in many people's minds that scientists agree on some topic, when no such agreement exists. 

We have an example of this in the paper I am discussing. It ends up bragging of "a significant consensus that extraterrestrial life likely does exist," even though its poll shows a fair fraction of the responding astrobiologists failing to declare that they "agree" or "strongly agree" with the idea that extraterrestrial life exists, and about a third of the responding astrobiologists failing to declare that they "agree" or "strongly agree" with the idea that "complex" extraterrestrial life exists. Given the ambiguity in the word "consensus," and that half of the public interprets that word to mean "unanimity of opinion," such a belief level should not be described as a consensus; it should merely be described as a majority opinion. In fact, because of problems discussed above, we do not even have here any very strong evidence that most astrobiologists or biologists agree that extraterrestrial life probably exists.  A well-designed set of neutrally-worded poll questions without the question bias documented above might well have shown fewer than half of the respondents agreeing that visible  extraterrestrial life exists. According to the poll, the number of astrobiologists agreeing that intelligent extraterrestrial life exists was 58%. That level of belief should never be described as a consensus, but a mere majority opinion. 

A poll like this would not mean much

Astrobiologists Play "Keep Torturing the Data Until It Confesses"

 In 2023 Nikku Madhusudhan and four other scientists created quite a stir. They authored a paper entitled "Carbon-bearing Molecules in a Possible Hycean Atmosphere." Researching a planet called  K2-18 b revolving around another star, the paper claimed to have found "potential signs of dimethyl sulfide (DMS), which has been predicted to be an observable biomarker in Hycean worlds." The term "Hycean worlds" refers to planets in other solar systems that may be entirely covered by an ocean. The term "biomarker" refers to something that may be a sign of life. A very simple compound, dimethyl sulfide is not any type of building block of life. But on Earth dimethyl sulfide is sometimes produced by life. 

But there were some reasons why the attempt to insinuate a biomarker was very dubious. One reason was that the claims about "potential signs of dimethyl sulfide" was a kind of "reading tea leaves" affair, in which scientists were analyzing the faintest of faint signals, rather like someone squinting at something on the horizon miles away. That type of observation offers plenty of opportunity to see what you want to see, by interpreting marginal hard-to-interpret just-barely-detectable data in some way that fits your cherished desires, rather than a hundred other ways. 

Then there is the fact that when scientists do observations like this, they are picking up signals from many different chemical sources, with the signals being all mixed up. It's a recipe for false alarms, rather like someone in a very crowded high school cafeteria trying to listen to what someone at a different cafeteria table far away is saying. 

Then there is the fact that the paper failed to detect any water at this planet. The paper stated 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 apparent non-presence of water at K2-18 b is a reason for thinking that life does not exist there.

Despite the paper's failure to detect water, and its weak mention of a mere mention of "potential signs of dimethyl sulfide," the world's "give us an inch and we'll take a mile" science news press began publishing a flood of misleading stories falsely claiming that some promising sign of life had been found. An example was this story on www.yahoo.com, which very badly misinformed 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 said 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. 

After the "sugar rush" of this flood of misleading stories, other scientists got busy examining the data on the distant planet K2-18 b, to see whether there was any decent evidence for dimethyl sulfide. In 2024 scientists produced a paper arguing that K2-18 b was not a "Hycaean" planet covered by an ocean, but instead a gas planet like Neptune with no ocean. The paper was "JWST Observations of K2-18b Can Be Explained by a Gas-rich Mini-Neptune with No Habitable Surface" authored by Nicholas F. Wogan and others. 

Then in early 2025 there was published the paper "A Comprehensive Reanalysis of K2-18 b's JWST NIRISS+NIRSpec Transmission Spectrum." It reanalyzed the data on K2-18 b and says "we find no statistically significant or reliable evidence for CO2 or DMS [dimethyl sulfide]." The paper had 16 authors, as compared to only five authors of Madhusudhan's paper. The 16 authors had found that Madhusudhan's claims about dimethyl sulfide at K2-18 b were unfounded. 

But now Madhusudhan is back with a new paper, trying to persuade us that dimethyl sulfide exists on K2-18 b. It is a paper entitled "New Constraints on DMS and DMDS in the Atmosphere of K2-18 b from JWST MIRI." He has some new observations, but only a scanty affair. It's a mere six hours of observations done with the James Webb Space Telescope, on April 26, 2025. Madhusudhan and his small team has put this data through some very arbitrary and gigantically convoluted analysis pipeline, one that was probably selected to maximize the chance of being able to claim that dimethyl sulfide exists on K2-18 b. The raw data gathered is shown below (Figure 1 from the paper).  Ignore the red line, which is not part of the raw data. 

Data like this does nothing to naturally suggest the existence of dimethyl sulfide. The James Webb Space Telescope has nothing like a "dimethyl sulfide detector" comparable to a carbon monoxide detector in a home. But it is possible for a scientist eagerly hoping to claim some evidence of dimethyl sulfide to arbitrarily analyze such data, to try and gin up something that can be claimed as evidence of dimethyl sulfide. 

At least seven long paragraphs of the paper discuss the incredibly elaborate rigmarole that is going on in Madhusudhan's analysis pathway.  It would be way, way too charitable to describe this analysis pathway as a Rube Goldberg machine. It would be more accurate to say that the analysis pathway is some incredibly weird analytic contraption that makes the crazy-looking machines of Rube Goldberg look simple and straightforward in comparison. Below is a paragraph giving us only one eighth of the "keep torturing the data until it confesses" craziness that was going on:

"We use the 1-D spectra time series to construct a white light curve (between 4.8-10 µm). We exclude the first 250 integrations, where the systematic trend is most extreme. We identify outliers on the white light curve, ± 2.5-σ from a rolling median, and replace the 1-D spectra corresponding to these outliers with linearly interpolated spectra from adjacent integrations. We scale the error bars on the light curve points such that the average error bar equals the observed standard deviation of the scatter in the out-of-transit residuals. We use emcee (Foreman-Mackey et al. 2013) to perform a Markov Chain Monte Carlo parameter estimation of the white light curve, fitting for a transit model with quadratic limb-darkening generated by pylightcurve (Tsiaras et al. 2016) multiplied by a systematic trend consisting of an exponential term and a linear term (as in section 2.1). In the white light curve, we fit for Rp/R∗, mid-transit time, a/R∗, i, quadratic limb-darkening coefficients and four parameters for the trend. Uniform priors are used except for a/R∗ and i, where we apply Gaussian priors based on values in Madhusudhan et al. (2023b) and use the Kipping parameterisation (Kipping 2013) for limb-darkening priors. We fix the period to 32.940045 days (Benneke et al. 2019a), the argument of periastron to 90o and the eccentricity to 0. The white light curve parameter estimates are given in Table 1." 

There are seven other paragraphs describing machinations and manipulations as bizarre and complex as these. It seems that at no point in these eight paragraphs do the authors give any justification for the weird convoluted spaghetti-code manipulations and transmogrifications that are occurring. There is nothing natural or straightforward about anything that is occurring.  Something comparable would be occurring if you took a photo of a pine tree, and passed it through many different arbitrarily selected photo filters, to finally end up with a photo looking like a sexy woman, without ever justifying your use of any of those filters. 

Finally the authors create some "model" that is basically a collection of guesses about 20 chemicals that might be in the atmosphere of this planet K2-18 b. Of course, their "model" includes their cherished gas dimethyl sulfide, because trying to gin up some evidence for that is the point of all these weird labors. Near the end of the paper, the authors triumphally announce that their model fits their pipeline-adjusted data.

This is pretty much just a big pile of baloney. No actual detection of dimethyl sulfide has occurred. The analysis pipeline is "keep torturing the data until it confesses" nonsense. There is no basis for any confidence in an analysis pipeline so convoluted and artificial.  We can conclude with 99% confidence that the described analysis pathway is untrustworthy. 

•  Nothing reliable has been done in this paper to show any likelihood of the existence of dimethyl sulfide on this planet K2-18 b. 
• Nothing reliable has been done in this paper to show any likelihood of the existence of any biomarker on this planet K2-18 b. 
• No observations have ever been done to show a likelihood that water exists on this planet  K2-18 b.
• In all likelihood (as suggested by the paper  of Wogan) the planet K2-18 b is a gas planet like Neptune, with neither an ocean nor a land surface, a type of planet that should be incapable of supporting life. Not just Wogan's paper but also this 2025 paper make this conclusion, with the paper stating, "Our results, therefore, render the mini-Neptune scenario the most likely interpretation for K2-18 b, given current observational constraints."

Imagine if you have took the six hours of data that Madhusudhan played with to get his results, and gave such data to ten different teams of astronomers, asking them to tell you what the data suggested, without telling where in space the data came from. Not even one of such teams would tell you that a biomarker had been found, and not one of them would say that any evidence of dimethyl sulfide had been found. Madhusudhan's funny business here merely shows that when scientists have their hearts set on reporting the existence of some thing they are eagerly hoping to find, and when they are willing to exert unlimited weird labors playing around with their data, then they may report finding some trace of what they were so fervently desiring to find. 

This is similar to what is going on in the world of neuroscience so frequently. Neuroscientists keep analyzing the noisy wavy blips of EEG readings, and they often report finding some faint sign of what they were eagerly hoping to find, after they subjected the data to many a strange convolution and contortion, in some arbitrary way, in a "keep torturing the data until it confesses" fashion. You can read about some examples of such a thing in my series of posts here. 

Postscript: An Ars Technica article published after this post is entitled "Skepticism greets claims of a possible biosignature on a distant world." We read this:

"The last issue is whether, if dimethyl sulfide is really present on K2-18b, it was produced by life as it is here on Earth. The answer appears to be 'possibly not': A 2024 paper indicates it's possible to produce the chemical through light-activated reactions."

A CNN article has a false clickbait headline, and a bad scientist misstatement.  But it least it has a good quote by astrophysicist Sara Seager, who states this:

"Now, with thousands of exoplanets in view, the temptation to overinterpret is strong — and some are jumping the gun. When it comes to K2-18 b, enthusiasm is outpacing evidence.”

The article also quotes a scientist named Schwieterman giving a technical reason for doubting that dimethyl sulfide was discovered at K2-18 b. 

To get an analogy what it is like for astronomers getting spectroscopic data from a distant planet, consider the visual below:

This text consists of many different sentences, overlaid on top of each other. Imagine trying to extract a particular word from such a mess. That's pretty much impossible. It's a similar deal for an astronomer getting spectroscopic data from another planet, because what such a person gets is signals from many different elements and compounds and chemicals, arriving all at once. Unless you are very lucky, there is almost no way to reliably extract which part is a signal from which chemical, compound or element. But with a mess like an astronomer gets in such a situation (or a mess like the one shown above), there are unlimited opportunities to see what you are fervently hoping to see. All that can be truthfully said about such a mess is something like this: "The data is too noisy for me to say much of anything reliable about it." 

I'm surprised to see some "question the hype" science journalism today in The Atlantic, where it's more typical to find credulous cheerleading of scientist boasts. Referring to Madhusudhan's team, an article there states this:

"The chemical [dimethyl sulfide] is one of several that could be responsible for the signal they found. And while it's the most likely one according to their models, others disagree." 

The article notes that dimethyl sulfide was found "in the dead, icy spray of a comet," meaning it isn't any reliable biomarker. "Abiotic" refers to something not involving life.  One paper is entitled "On the abiotic origin of dimethyl sulfide: discovery of DMS in the Interstellar Medium." Another paper is entitled "Evidence for Abiotic Dimethyl Sulfide in Cometary Matter."

In the Atlantic article we read a quote by astronomer Ignas Snellen stating that Madhusudhan's framing of his research is "irresponsible nonsense." 

Madhusudhan's overenthusiasm reminds me of the overenthusiasm of another astronomer, Avi Loeb. Harvard astronomer Avi Loeb somehow got the idea that a  2014 meteor (the CNEOS 2014-01-08 meteor) may have been an interstellar spacecraft that blew up high in the sky. Loeb ran a million-dollar oceanic expedition looking for what he hoped would be remnants of a crashed extraterrestrial spaceship, an expedition he organized.  He found no sign of anything looking like a spaceship or any of its parts. Loeb claims to have found tiny round specks only about a millimeter in size. All that he recovered were some tiny metal specks. The metal specks he found are just like metal sea specks found all over the world.  But  Loeb tried to suggest that he may have discovered smithereens of an exploded interstellar spacecraft. 

There was nothing special about the specks Loeb and his team gathered (as I discuss here), and there is nothing special about the data Madhusudhan got from K2-18 b. Madhusudhan's readings are just like the readings from quite a few extrasolar planets that must be lifeless because they are outside of the habitable zone of the stars they revolve around. Loeb got a nice book deal out of his glory-hounding efforts, and one can wonder whether Madhusudhan's similar efforts may eventually pay off financially for him. 

A National Geographic page interviews some experts about Madhusudhan's recent claims. Some excerpts:

" 'I'm pretty skeptical of this claim, and I wish the press coverage better reflected the skepticism of the astronomical and astrobiological community,' wrote astrobiologist Joshua Krissansen-Totton of the University of Washington in an email....Another researcher, astronomer Ryan MacDonald at the University of Michigan went further, criticizing the three sigma claim as 'statistical hacking' on Bluesky....'The simplest explanation of this planet is a very thick gas-giant atmosphere with no habitable surface,' says exoplanet scientist Nick Wogan of NASA Ames. ...And we already know that nature can produce DMS [dimethyl sulfide] without life. Last year, chemist Nora Hänni at the University of Bern and her colleagues found DMS on comet 67P—not exactly a habitable world. Other researchers have found it in interstellar space. And last year, chemist Eleanor Browne of the University of Colorado, Boulder and her colleagues showed that DMS can be produced in light-fueled chemical reactions in lab experiments with synthetic atmospheres.

'There's no reason to understand [DMS] as a unique consequence of life,' says Mathis. 'I just, for the life of me, cannot figure out exactly what the argument is about: why they think this could even potentially be indicative of life, given that we've seen abiotic sources.' ”

Post-postscript: An article at Gizmodo.com quotes some experts discussing Madhusudhan's recent paper:

Planetary chemist Oliver Shorttle says "I do not believe the report of DMS in the spectrum of K2-18 b moves the astrobiological needle." He states this:

"There is presently no requirement from the data that this planet hosts liquid water oceans and a climate amenable to life. In fact, based on the data there is every reason to believe the climate will be far too hot for liquid water oceans, with the deep atmosphere potentially being underlain by oceans of magma, not liquid water. For this reason, even if 1 and 2 return a DMS detection, our expectation should be that this [molecule] has emerged in a lifeless, hot, sulfur and hydrogen rich atmosphere and ask ourselves what the atmospheric chemistry is that would have enabled this. Believing instead that this is DMS of biological origin would require overturning our every expectation as to the climate of this planet, without any other reason to do this from the data."

Astrophysicist Ignas Snellen says this:

"The whole thing is completely blown out of proportions.... The research team finds bumps in their spectrum. It is not clear whether these are real, and if so, what they could be caused by. There could be dozens of molecules (if real), or even cloud features. What do the authors do? They just look whether DMS [dimethyl sulfide] could cause this (and add DMDS). They ignore the dozens of other species [i.e. non-biological sources of molecules] that could cause this bump and call it a day. If I had been the referee, I would have stopped this publication right there. There is no reason to invoke astrobiology, let alone call it the biggest breakthrough or whatever....In the long run this will hurt astronomy when nobody will take us seriously anymore."

An NPR story says that  a scientist has analyzed the most recent data from K2-18 b, and has found it has no signal of any kind. We read this:

"The results he got suggested that there's too much noise in the data to draw any conclusions. Rather than seeing a bump or a wiggle that indicated a signal, 'the data is consistent with a flat line,' says Taylor, adding that more observations from the telescope are needed to know what can be reliably said about this planet's atmosphere."

Physics professor Peter Coles has this to say on this topic:

"The DMS and DMDS in the title refer to Dimethyl Sulphide and Dimethyl Disulphide respectively. These are interpreted by the authors as biosignatures. There are two main problems with this claim. One is that DMS and DMDS are not necessarily biosignatures in the first place; see here for the reasons. The other is that there isn’t even any evidence for the detection of DMS or DMDS anyway...In statistical terms this is a non-detection. The Bayes Factor used in the paper to quantify the evidence for a model with DMS and/or DMDS over one without is just 2.62 in the logarithm. That’s not a detection by any stretch of the imagination; to be anywhere near convincing a Bayes Factor has to be at least 100. The subsequent cherry-picking of the data to improve the apparent probability of a detection is just statistical flummery....That the claim has somehow morphed into the 'the strongest evidence for life beyond our solar system' is absurd. The most charitable thing I can say is that Prof. Madhusudhan must have been carried away by enthusiasm. This doesn’t reflect very well on Cambridge University either."

Around May 22 we had the paper "Insufficient evidence for DMS and DMDS in the atmosphere of K2-18 b. From a joint analysis of JWST NIRISS, NIRSpec, and MIRI observations." Dismissing claims that any biomarkers or signs of life were found at planet K2-18 b, the paper concludes this:

"Our joint analysis of the panchromatic (0.6 - 12 um) spectrum of K2-18 b finds insufficient evidence for the presence of DMS [dimethyl sulfide] and/or DMDS [dimethyl disulfide] in the atmosphere of the planet. Furthermore, other molecules containing methyl functional groups (e.g., ethane) with absorption bands similar to DMS/DMDS provide an equally good fit to the data. We find that any marginal preferences are the result of limiting the number of molecules considered in the model and oversensitivity to small changes between data reductions. Our results confirm that there is no statistical significance for DMS or DMDS in K2-18 b's atmosphere."

Post-post-postscript: A November 2025 article is entitled "Latest update on alien planet with ‘best ever signs of life’ reveals sad development." We read this:

"It seems the world might have jumped the gun when rolling out the welcome wagon for the alien planet with the 'highest ever' signs of life....Renyu Hu, a planetary scientist and astronomer at NASA's Jet Propulsion Laboratory, and his colleagues once again used the JWST to conduct further analysis of K2-18b. And sadly, they could not find any 'conclusive evidence for the existence of this molecule [dimethyl disulfide] in the atmosphere' after taking another look."

In the same month we had a paper by 10 scientists, one entitled "K2-18b Does Not Meet the Standards of Evidence for Life."

In June 2026 we had an article by Peter Vickers in which he said that he did a poll of "hundreds of astrobiologists" asking them about whether life had probably been found on K2-18b. He says that the poll was done "within days" of the initial report boasting about a biosignature on K2-18b. According to the poll, "only 6.6 per cent of surveyed astrobiologists agreed that scientists had probably found extraterrestrial life." Doing such a poll only a few days after the initial press report is not a very good technique. What often happens is that there is initial excitement, which is dampened when other scientists "throw cold water" on the initial report, giving reasons for doubting it. That's what happened in the case of the BICEP2 false triumphal announcement. A better time to take an opinion survey is 6 months after the initial boastful announcement.