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Alien life is out there. But our theories are steering us away from it.

Exoplanet with an atmosphere.
(Image: © Shutterstock)

If we discovered evidence of alien life, would we even realize it? Life on other planets could be so different from what we're used to that we might not recognize any biological signatures that it produces.

Recent years have seen changes to our theories about what counts as a biosignature and which planets might be habitable, and further turnarounds are inevitable. But the best we can really do is interpret the data we have with our current best theory, not with some future idea we haven't had yet.

This is a big issue for those involved in the search for extraterrestrial life. As Scott Gaudi of Nasa's Advisory Council has said: "One thing I am quite sure of, now having spent more than 20 years in this field of exoplanets … expect the unexpected."

But is it really possible to "expect the unexpected"? Plenty of breakthroughs happen by accident, from the discovery of penicillin to the discovery of the cosmic microwave background radiation left over from the Big Bang. These often reflect a degree of luck on behalf of the researchers involved. When it comes to alien life, is it enough for scientists to assume "we'll know it when we see it"?

Many results seem to tell us that expecting the unexpected is extraordinarily difficult. "We often miss what we don't expect to see," according to cognitive psychologist Daniel Simons, famous for his work on inattentional blindness. His experiments have shown how people can miss a gorilla banging its chest in front of their eyes. Similar experiments also show how blind we are to non-standard playing cards such as a black four of hearts. In the former case, we miss the gorilla if our attention is sufficiently occupied. In the latter, we miss the anomaly because we have strong prior expectations.

There are also plenty of relevant examples in the history of science. Philosophers describe this sort of phenomenon as "theory-ladenness of observation". What we notice depends, quite heavily sometimes, on our theories, concepts, background beliefs and prior expectations. Even more commonly, what we take to be significant can be biased in this way.

For example, when scientists first found evidence of low amounts of ozone in the atmosphere above Antarctica, they initially dismissed it as bad data. With no prior theoretical reason to expect a hole, the scientists ruled it out in advance. Thankfully, they were minded to double check, and the discovery was made.

More than 200,000 stars captured in one small section of the sky by NASA's TESS mission.

More than 200,000 stars captured in one small section of the sky by NASA's TESS mission. (Image credit: NASA)

Could a similar thing happen in the search for extraterrestrial life? Scientists studying planets in other solar systems (exoplanets) are overwhelmed by the abundance of possible observation targets competing for their attention. In the last 10 years scientists have identified more than 3,650 planets - more than one a day. And with missions such as NASA's TESS exoplanet hunter this trend will continue.

Each and every new exoplanet is rich in physical and chemical complexity. It is all too easy to imagine a case where scientists do not double check a target that is flagged as "lacking significance", but whose great significance would be recognized on closer analysis or with a non-standard theoretical approach.

However, we shouldn't exaggerate the theory-ladenness of observation. In the Müller-Lyer illusion, a line ending in arrowheads pointing outwards appears shorter than an equally long line with arrowheads pointing inwards. Yet even when we know for sure that the two lines are the same length, our perception is unaffected and the illusion remains. Similarly, a sharp-eyed scientist might notice something in her data that her theory tells her she should not be seeing. And if just one scientist sees something important, pretty soon every scientist in the field will know about it.

History also shows that scientists are able to notice surprising phenomena, even biased scientists who have a pet theory that doesn't fit the phenomena. The 19th-century physicist David Brewster incorrectly believed that light is made up of particles traveling in a straight line. But this didn't affect his observations of numerous phenomena related to light, such as what's known as birefringence in bodies under stress. Sometimes observation is definitely not theory-laden, at least not in a way that seriously affects scientific discovery.

We need to be open-minded

Certainly, scientists can't proceed by just observing. Scientific observation needs to be directed somehow. But at the same time, if we are to "expect the unexpected", we can't allow theory to heavily influence what we observe, and what counts as significant. We need to remain open-minded, encouraging exploration of the phenomena in the style of Brewster and similar scholars of the past.

Studying the universe largely unshackled from theory is not only a legitimate scientific endeavor — it's a crucial one. The tendency to describe exploratory science disparagingly as "fishing expeditions" is likely to harm scientific progress. Under-explored areas need exploring, and we can't know in advance what we will find.

In the search for extraterrestrial life, scientists must be thoroughly open-minded. And this means a certain amount of encouragement for non-mainstream ideas and techniques. Examples from past science (including very recent ones) show that non-mainstream ideas can sometimes be strongly held back. Space agencies such as NASA must learn from such cases if they truly believe that, in the search for alien life, we should "expect the unexpected."

Peter Vickers, Associate Professor in Philosophy of Science, Durham University

This article was originally published at The Conversation. The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights.

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  • rod
    Admin said:
    Alien life is out there, but our current theories seem to be steering us away from it, says this scientist.

    Alien life is out there. But our theories are steering us away from it. : Read more

    As the report concludes "In the search for extraterrestrial life, scientists must be thoroughly open-minded. And this means a certain amount of encouragement for non-mainstream ideas and techniques. Examples from past science (including very recent ones) show that non-mainstream ideas can sometimes be strongly held back. Space agencies such as NASA must learn from such cases if they truly believe that, in the search for alien life, we should "expect the unexpected."

    Currently we have 4168, confirmed exoplanets, The Extrasolar Planets Encyclopaedia
    Presently, none are confirmed with alien life on them. The geocentric solar system debate vs. heliocentric solar system, developed verifiable, repeatable observations and testing to overcome the geocentric paradigm in astronomy that dated back to Claudius Ptolemy and earlier. Tycho Brahe made efforts to show Mars parallax at Mars opposition, placed Mars farther away from Earth than the Sun but failed, Tycho did not refute Copernicus. This is just one example. There is also the history of meteorite ALH84001 (1996) and what happened with this space rock and life on Mars announced in 1996. Rigorous testing and repeatable verification standards should not be set aside to promote a *new paradigm* as sound science.
    Reply
  • Mike'nSpace
    All this psycho-babble and talk about how open mindedness is key are just simply missing the primary point to why science is taboo to most. A human learns to communicate around the three year old time frame. Most humans start formal schooling at 6-7. And what happens, in regards to education, during that initial 3-4 yr span; most humans are introduced to religion. Not only that, but actively discouraged to explore, experiment and be curious. How I have heard it put; we teach our children to walk and talk then tell them to sit down and shut up.

    Often kids are refereed to as "sponges" and will pick up on anything. Translate; as very young humans learning is easy and an opportune time to mold and instill fundamentals to produce a productive older human. However, all that is being instilled in our young humans is metaphysical bull-cockery, don't question religious elders and never contradict the biblical word.

    If, in fact, that beginning time could be spent empowering our young humans that they have the ability to be skeptical, always ask the tough questions and that in experimentation is the only way to discover the truth.
    Reply
  • Sunspot
    I am fairly new to Space.com, but as a lifelong amateur astronomer, I'm disappointed to see this article here. I come here for real science. UFOs are not real science. There is absolutely no evidence that UNIDENTIFIED flying objects are spacecraft piloted by alien species, much less by future, time-traveling humans. I enjoy science fiction as much as any scientist, but I feel we must resist the temptation to include "sciency" topics here. The day I see an article taking astrology seriously will be the last day I come to Space.com.
    Reply
  • Garret Moore
    We are a Pre-Intelligent species. Still limited in our allowed imaginations by the political, dogmatic and corporatized sciences. An individual's experience can even recognize what science cannot. That tells us how far behind reality science truly is. Aliens? The math says yes, Astronomy says highly probable but most the rest of the sciences prefer to categorize such a possibility as a threat to their practical self-concerned stability. Religion went through this cognitive dissonance stage before the new paradigm of Science took hold too. Pure science would naturally take us there, but it is easy to see why the current conditions and ill-informed and subjective sub-sciences and even some myopic opinions are more of a thick stagnant, politically and an economically polluted river that has at least slowed to a crawl or even has stopped flowing and might never reach the ocean of knowledge that is promised to an unencumbered and naturally evolving intelligence.
    Reply
  • FN Moeller

    On warm wet planets life will be VERY similar. The similarities will be the most striking finding. If the available elements are the same we will likely find many of the same biochemical processes. Yes many of the genes will have earth counter parts. Designs will be similar. If you don't know how I know this ask.

    Life that may evolve in places other than warm wet planets, in space for example. If something like this does indeed exist it will be very different. In fact it may already be right before our eyes.

    Reply
  • Mental Avenger
    FN Moeller said:
    You can reasonably say that you are not convinced but if you think there is no evidence you are clearly not qualified for the discuss. So why are you posting?
    Sunspot is correct. There is no evidence that UFOs are piloted by ET Aliens. None. Zero. If you think you have some credible, verifiable evidence to the contrary, please post it here.
    Reply
  • Mm70rj
    With a few changes I could replace "aliens" by "ghosts" in this article... sometimes the easiest answer is the most likely to be right... Mankind has been trying to find alien life for the last 30 years... and nothing so far... two options: there is no life out there (at least not as abundant as previously thought) OR the search methology is wrong... you pick your answer...
    Reply
  • Malcolm J. Brenner
    Alien life?

    What could be more alien than a creature that can navigate in pitch darkness, communicate abstract ideas, withstand +400 psi pressures that collapse its rib cage, swallows its food whole and headfirst, doesn't use any technology, has a larger, more convoluted brain than humans?

    Dolphins. We humans have been mostly ignoring them since we came down from the trees. John C. Lilly notwithstanding, they are creatures that have watched us evolve, and could, if we approach them correctly, tell us a lot about ourselves and that part of the world where most of our senses and our technology are almost useless, the ocean.

    But I know them to be creatures of sophistication and intelligence, capable of the emotion of love and devotion.

    Best of all, nobody doubts their existence!
    Reply
  • Sunspot
    FN Moeller said:
    You can reasonably say that you are not convinced but if you think there is no evidence you are clearly not qualified for the discuss. So why are you posting?
    Show me the evidence! If you believe that the human race has proof of space aliens, you should not be posting on a science site, you clearly don't understand the difference between real science and science fiction.
    Reply
  • petervickers
    Sunspot said:
    I am fairly new to Space.com, but as a lifelong amateur astronomer, I'm disappointed to see this article here. I come here for real science. UFOs are not real science. There is absolutely no evidence that UNIDENTIFIED flying objects are spacecraft piloted by alien species, much less by future, time-traveling humans. I enjoy science fiction as much as any scientist, but I feel we must resist the temptation to include "sciency" topics here. The day I see an article taking astrology seriously will be the last day I come to Space.com.

    Hi, I should have written 'extraterrestrial life', not 'alien life'. That was the only mistake. By 'alien life' I actually meant life of an alien kind. I wasn't talking at all about UFOs. The kind of thing I'm thinking of is the case of the discovery of 51 Peg b. Scientists had looked for Jupiter-size planets with the wobble method, but theory dictated that such planets couldn't exist at short period orbits. Gordon Walker searched with the wobble method between 1980 and 1992, but never checked his data for planets with an orbital period under 40 days. Marcy and Butler made the same mistake. Then in 1995, as I'm sure you know, Mayor and Queloz discovered 51 Peg b with an orbital period of only 4 days. Walker later wrote "We had all been looking in the wrong place". This is what I'm thinking of: cases where our theories bring us to look in the wrong place, or, even if we do look in the 'right place', we miss the significance of what we're looking at because of how our theories bias our thinking.
    Reply