The Bad Argument Experts Keep Giving When Asked About Extraterrestrial Life

For many decades scientists have been asked about the possibility of extraterrestrial life.  Again and again they have been posed these questions:

• Are we alone in the universe?
• Is there life on other planets?
• Is there intelligent life on other planets?
• Do extraterrestrial civilizations exist?

It seems that a large fraction of the time that scientists are asked these questions,  they reply by giving a fallacious argument. One such argument may be called the "many chances equals many successes" argument. The argument may be stated like this:

"There are billions of planets in our galaxy, so there must be many planets on which life exists."

"There are billions of planets in our galaxy, so there must be many planets with extraterrestrial civilizations."

"There are a vast number of planets in our universe, so life must have arisen many times."

"There are a vast number of planets in our universe, so there must be very many civilizations on other planets."

"There are a huge number of planets in our universe, so there must be many other extraterrestrial civilizations."

A very similar  argument may be called the "many chances equals some successes" argument. The argument may be stated like this:

"There are billions of planets in our galaxy, so there must be some  planets on which life exists."

"There are billions of planets in our galaxy, so there must be some planets with extraterrestrial civilizations."

"There are a vast number of planets in our universe, so life must have arisen on some other planets."

"There are a vast number of planets in our universe, so there must be some other civilizations on other planets."

"There are a huge number of planets in our universe, so there must be some other extraterrestrial civilizations."

Let us look at some examples of experts using this very fallacious argument. In a recent article in The Conversation (reprinted here) asking scientists about whether extraterrestrial life exists, astrobiologist Jonti Horner stated this:

"Space is unbelievably big. In the last few decades, we've learned almost every star in the cosmos has planets. Our galaxy, the Milky Way, is estimated to have up to 400 billion stars. If each of those has five planets, we'd have two trillion planets in our galaxy alone. And we know there are more galaxies in the cosmos than there are planets in the Milky Way. In other words, there's a lot of real estate out there. And with so much variety, I find it impossible to believe Earth is the only planet that has life – including intelligent and technologically-advanced life."

So Horner is arguing this: "many chances equals some successes."  In the same article, an equally fallacious statement of the same bad argument is given by astrophysicist Steven Tingay, who states the following, after answering "Yes" to the question of "Do aliens exist?":

"The Universe contains hundreds of billions of galaxies, each of which can be composed of up to billions and billions of stars. Most of these stars have at least one planet each. These planetary systems form out of a rich mixture of elements, including all the elements regarded as essential for 'life'. So, it is hard to believe that the particular mix of conditions that resulted in 'life' only occurred on Earth, and not on the trillions of other planets in the Universe."

So Tingay is arguing  "many chances equals some successes" and is insinuating "many chances equals many successes."  In the same article, an equally fallacious statement of the same bad argument is given by Rebecca Allen, who states this:

"There are more than 100 billion planets estimated to exist in our galaxy alone (with some six billion potentially being Earth-like). Therefore, the probability that life exists elsewhere is all but confirmed."

In the same article, scientist Helen Maynard-Casely gives the worst of the five answers by experts, by stating this:

"I'm of the opinion that it's only a matter of time before we find something that resembles biology somewhere other than on Earth. This is because we're increasingly finding various potential pockets in our solar system that may be hospitable to life as we know it."

This reasoning can be summarized as "some chances equals at least one success," which is like "many chances equals some successes," but even more fallacious. Similarly, before stating with unwarranted confidence that he is "quite certain" we have not been visited by aliens in his lifetime, SETI astronomer Seth Shostak states this in a recent interview:

"But there are roughly a trillion planets in the Milky Way galaxy. Buy a trillion lottery tickets, you're going to win."

Here again we have "many chances equals some successes" reasoning. Similarly, in Scientific American the Harvard astronomer Avi Loeb states the following, which states once again the "many chances equals some successes" argument:

"So if you roll the dice on life billions of times in the Milky Way, what is the chance that we are alone? Minuscule, most likely!"

Such reasoning is completely fallacious. It is not at all true in general that "many chances equals many successes." It is also not at all true in general that "many chances equals some successes" or even that "many chances equals at least one success." If the probability of something happening is sufficiently low, then we should expect many chances to yield zero successes.  So "many chances" does not necessarily equal "many successes," and "many chances" does not necessarily equal "some successes" or even one success. For example:

• If everyone in the world threw a deck of cards into the air 1000 times, that would be almost 10 trillion chances for such flying cards to form into a house of cards, but we should not expect that in even one case would the flying deck of cards accidentally form into a house of cards. 
• If a billion computers around the world each made a thousand attempts to write an intelligible book by randomly generating 100,000 characters, that would be a total of a trillion chances for an  intelligible book to be accidentally generated, but we should not expect that even one of these attempts would result in the creation of an intelligible book. 
• If you buy a million tickets in a winner-take-all lottery in which the chance of winning is only 1 in 100 million, you should not expect that any one of those tickets will succeed in winning such a lottery. 

Below are some very general observations about probability:

• It is not necessarily true that many chances (also called trials) will yield many successes. 
• It is not necessarily true that many chances (also called trials) will yield some successes or even one success. 
• If the chance of success on any one trial multiplied by the number of trials gives a number less than 1, we should not expect that even one of the trials will produce a success.
• If the chance of success on any one trial multiplied by the number of trials gives a number greater than 1, we should  expect that at least one of the trials will produce a success.

Here are some examples illustrating the last two of these principles.  Let us suppose that the chance of winning a prize in a particular lottery is 1 in 1000. If you buy more than 1000 tickets in this lottery, you should expect to win a prize, because the chance of winning on any trial multiplied by the number of trials is greater than 1 (1.001 to be exact).  If you buy fewer than 1000 tickets in this lottery, it will be unlikely that you win. For example, if you bought 900 tickets in such a lottery, the chance of winning on any trial (.001) multiplied by the number of trials (900) would equal .9. Since that number is less than 1, you should not expect to win even once.  

A binomial probability calculator can be used to verify such principles. Such a calculator will use a mathematical approximation method to get a rough idea of probabilities, given a particular number of trials, and a particular chance of success. For example, using the binomial probability calculator at Stattrek.com, we find the following:

The last of these lines verifies that the likelihood of at least one success is slightly greater than 50 percent if there are 1001 trials that have each a chance of success of 1 in 1000. 

So how should we calculate the chance of extraterrestrial life existing on at least one planet revolving around any star in the universe? We should judge whether the chance of success on any one trial (the chance of life appearing on a random planet) multiplied by the estimated number of planets in the observable universe is a number greater than 1.  The number of stars in the observable universe has been estimated as a billion trillion. Given about 10 planets per star, we can estimate the number of planets in the observable universe as ten billion trillion (10,000,000,000,000,000,000,000). 

Roughly speaking, if the chance of life randomly appearing on the average planet is greater than 1 in 10,000,000,000,000,000,000,000, we should expect that life exists on at least one other planet. But if the chance of life randomly appearing on the average planet is less than 1 in 10,000,000,000,000,000,000,000, we should expect (given only chance) that no life exists outside of our solar system. 

Unfortunately for extraterrestrial life enthusiasts, there is every reason for suspecting that the chance of life appearing on any random planet (because of accidental chemical combinations) is very, very much less than 1 in 10,000,000,000,000,000,000,000.  Even the simplest microbe requires 50 or more types of functional protein molecules.  An average functional protein molecule consists of hundreds of amino acids arranged in just the right way to acheive a functional result.  It has been estimated that the probability of a functional protein molecule forming by chance is less than 1 in 10 to the hundredth power. 

Here the math tells a decisive tale.  It seems that by chance that nowhere in the observable universe would there form even one of the functional protein molecules needed for life. But more than 50 types of such molecules would be needed for even the simplest thing to exist. Even the simplest microbe is like a purposeful arrangement of many thousands of amino acids parts, just as a 50-page instruction manual is a purposeful arrangement of about 15,000 letters. 

But there are two complications which cloud the issue. The first is the possibility that there may be unknown natural reasons why it would be inevitable that life appears whenever it has the chance. Materialists often appeal to such a possibility, but never have done anything to substantiate such an idea.  Such a possibility is simply a "magic lamp" conveniently evoked by many materialists. 

Another complication is that perhaps it is not mere chance that controls the odds of life appearing on other planets. It is quite possible that there is some divine force "loading the dice," making the fantastically improbable occur very often.  If there is such an ageny (which might be something that occurs through direct action or indirectly through special laws not yet discovered that increased the chance of life appearing), then "all bets are off" in regard to probabilities.  In fact, it is quite possible that despite basically impossible odds of life forming by chance on any planet, that the universe is teeming with life and possibly even intelligent life,  simply because some creative divine design force is at work in the universe. 

A further complication is that the chance of intelligent life appearing on some planet is not at all equal to the chance of some life appearing on some planet. The first probability may be a trillion or a billion trillion quadrillion times smaller than the first.  Contrary to the triumphalist boasts of Darwinism adherents,  no one has shown that intelligent life or even multicellular life inevitably follows from the existence of microscopic life, nor has anyone even shown that eukaryotic cells (the more complex kind of cells) should inevitably appear once prokaryotic cells (the simpler kind of cells) exist. 

Clearly estimating the likelihood of extraterrestrial life and extraterrestrial civilizations becomes quite complex when we consider all of the factors that should be considered.  When asked about whether extraterrestrial civilizations exist, an intelligent answer for an expert to give might be something like this:

"Calculating the chance of extraterrestrial life or extraterrestrial civilizations is very complicated, and very dependent upon the assumptions made. Under one reasonable set of assumptions, there could be a great number of extraterrestrial civilizations. Under a different reasonable set of assumptions, there would probably be no extraterrestrial life anywhere in the universe."

Rather than giving that type of intelligent answer, we so often get the stupid little sound bite of fallacious reasoning equivalent to "many chances equals many successes" or "many chances equals some successes."  Our experts seem so often to go into "childish reasoning mode" when talking about the likelihood of extraterrestrials. On a NASA page we have some reasoning (based on the number of stars in the observable universe) that "human civilization is likely to be unique in the cosmos only if the odds of a civilization developing on a habitable planet are less than about one in 10 billion trillion, or one part in 10 to the 22nd power."  An astronomer then says this:

"One in 10 billion trillion is incredibly small. To me, this implies that other intelligent, technology producing species very likely have evolved before us."

Of course, reasoning based on a feeling or impression about whether a number is "incredibly small" (or a suspicion that "incredibly small" probabilities should not exist) bears no resemblance to scientific or philosophical reasoning.  There is no rule that probabilities cannot be incredibly small, and anyone should be able to think of thousands of real probabilities that are much smaller than 1 in a billion trillion.  In life and nature, there exist billions and trillions of probabilities very much smaller than 1 in 10 billion trillion.  The astronomer's reasoning is as silly as the argument below:

"Someone estimated that if I type random characters while blindfolded all day, the chance of me producing a best-selling book will be less than 1 in 10 to the hundredth power. Less than 1 in 10 to the hundredth power is incredibly small. So if I type random characters while blindfolded all day, I probably will produce a best-selling book."

When asked about whether extraterrestrials exist elsewhere in space, a scientist should tell us about the very high amount of organization and functional complexity in even the simplest living thing, and why that has that such a great effect on the odds of extraterrestrial life appearing. Virtually never will a scientist do such a thing. In this regard, our scientists act like someone who is asked, "What will happen if I jump from a flying airplane?" and who fails to mention the little detail that you will be killed. 

Over my long life I must have read 1000 answers by scientists when asked about the likelihood of extraterrestrial life, but I cannot recall any of them ever giving the type of answer that should be given, which is an answer like the "under one reasonable set of assumptions" answer quoted above, or an answer something like this:

"Even the simplest living thing is so functionally complex and organized that the chance of life accidentally appearing from non-life is fantastically small, very much less than 1 divided by the number of planets in the observable universe. If there is some intelligent agency that has acted to help make life appear, life and perhaps even intelligent life could exist throughout our galaxy and throughout the universe. If no such agency exists, we should expect that life does not exist on any other planet in the observable universe."

In general, over the past 50 years expert responses to questions about the likelihood of extraterrestrial life have usually been of poor quality.  The two main relevant factors that need to be discussed are the extreme difficulty and very high mathematical improbability of abiogenesis (life forming from non-life on a particular planet), and the number of planets in the observable universe.  Experts almost never discuss the first of these things when asked about the likelihood of extraterrestrial life, just as they almost never realistically discuss the gigantic degree of hierarchical organization and fine-tuned dynamism in large living things (just as if they were trying to make us think that living things are a billion times simpler than they are). Many of the answers given to "are there extraterrestrials out there" questions include misinformation, such as the untrue claim often made by Carl Sagan that the building blocks of life exist abundantly in outer space.  (The building blocks of microscopic life are functional proteins, which have never been detected in outer space; and almost none of the different building blocks of the building blocks of life have been found in outer space, since no more than about one or two of the 24 amino acids and nucleotides used by life have been found in space.)   The failure of decades of SETI efforts to pick up extraterrestrial radio signals is conveniently ignored by almost all experts asked about the likelihood of extraterrestrial life.  Then there is a frequent use of "most experts agree" claims, which are never backed up by specific evidence that such a majority of opinion exists. 

Postscript: in a Forbes article we read this quote from scientist Peter Ward:

“I would bet my life in an instant that there are other intelligent species in our galaxy,” said Ward. “The numbers are too great to believe otherwise.”

We see here an example of the all-too-common reality of a scientist having absolute dogmatic confidence in a fallacious argument. The phrase "the numbers are too great" refers to the number of planets in our galaxy. So the reasoning is "many chances equals at least one success," which is a completely fallacious argument for the reasons given above.  This is also an example of the all-too-common reality of a scientist having an absolute unshakable faith in something contrary to the low level facts he has gathered. Ward previously wrote a book listing many reasons why planets as favorable to life as Earth should be rare.  Indeed a recent headline on www.space.com has a title "None of the alien planets we know of could sustain life as we know it, study finds." The article states, "Astronomers know enough about the nature of stars in the Milky Way to assume that the right conditions for photosynthesis-driven life might be rare."