Alien Life? Why The Drake Equation Fails
Most of us have seen the Drake equation, in one its many forms, which purports to put a number on how many alien civilizations have iPhones. There has been much discussion on the original and its variants since Drake first published in 1961.
All attempts, I claim, share the same failing, as we’ll see. This is also related to the so-called Fermi paradox, also mentioned below.
Two fellows, Frank and Sullivan, have another go. The lite version of their peer-reviewed paper is in (appropriately) the New York Times with the title “Yes, There Have Been Aliens“. The full version is the “A New Empirical Constraint on the Prevalence of Technological Species in the Universe” in Astrobiology.
From the Times:
Instead of asking how many civilizations currently exist, we asked what the probability is that ours is the only technological civilization that has ever appeared. By asking this question, we could bypass the factor about the average lifetime of a civilization. This left us with only three unknown factors, which we combined into one “biotechnical” probability: the likelihood of the creation of life, intelligent life and technological capacity.
You might assume this probability is low, and thus the chances remain small that another technological civilization arose. But what our calculation revealed is that even if this probability is assumed to be extremely low, the odds that we are not the first technological civilization are actually high. Specifically, unless the probability for evolving a civilization on a habitable-zone planet is less than one in 10 billion trillion, then we are not the first.
You can already see that abuses of probability are coming up. From the paper:
We define the “A-form” of the Drake equation, which describes the total number of technological species that have ever evolved anywhere in the currently observable Universe:
A = [N* fp np][fl fi ft]
…where N* is the total number of stars [the asterisk is a star, not multiplication], fp is the fraction of those stars that form planets, np is the average number of planets in the habitable zone of a star with planets, fl is the probability that a habitable zone planet develops life, fi is the probability that a planet with life develops intelligence, and ft is the probability that a planet with intelligent life develops technology (of the “energy intensive” kind such as that of our own civilization).
After this comes manipulations of the equation which aren’t especially interesting. There are no insurmountable problems in the leading elements of this (or modifications of this) equation. But there is a universe of trouble with the terms in the brackets, [fl fi ft].
All of these elements are said to be probabilities. So, focus on probability’s Golden Rule: All probabilities are conditional. From that simple and honest truth flows everything, including the proof that the Drake equation, modified or no, has no meaning as it stands.
Let’s step through each probability.
The first, fp, is also the least: the fraction of stars with habitable planets. Least trouble I mean, because scientists can be confident (not that they’re right, just confident) they have a handle on the causes behind the creation of these planets. So natural will be giving a number to this one, with strong tacit premises on planet formation, that it won’t even seem like a probability to most scientists.
Then comes fl, the probability a planet develops life. Since nobody knows scientifically how life began (on Earth), premises which can fix fl are hard to come by. One can make up a number here, and anywhere, based on gut feelings, of course. But what does that number mean? It is the premises in any probability that are important, and here there are only vague notions. If we knew, and were not bluffing about knowing, how biogenesis occurs, then we’d be on solid ground. We do not know, so aren’t.
The next element, fi, is the probability of something like “Rational creatures on other planets exist”. Proponents must therefore have some kind of causal theory of how rational creatures, i.e. animals with intellects and wills, came to be. You further need a strict definition of mind, consciousness, intellect, and will. Naturally, one working theory about all this is denied by many scientists.
So, seeking elsewhere, in order to calculate fi, we would need a list of accepted premises that unambiguously lead to a unique number, or at least to a tight interval. None exist: none that are acceptable and agreed to by all, I mean. Plentiful premises exist that might be used, of course. You might say, “7 out of 10 planets with life develop rational creatures” and thus fi = 0.7. But who would agree to these premises? It is mere whim.
Finally, ft, “the probability that a planet with intelligent life develops technology (of the ‘energy intensive’ kind such as that of our own civilization).” What might the premises be? Specifically, and in the detail required to give ft.
For man, given (conditionally on) we have observed such development, the probability is 1. For aliens? You have to have a causal theory of civilizational development in alien minds. State it.
But forget all that. I think most who wield the Drake and its variants cherish the probability 1. That is, I’d wager at least a majority of those who study Drake already believe other “intelligent civilizations” exist, and want to make that belief appear more scientific, hence the need to put numbers to their belief: modern science rests on numbers. Their real interest is not estimating whether ICs exist, but how many exist, a number which is believed to be above one.
Which leads to the Fermi paradox. It takes (sort of) the Drake as a premise and asks, if ICs “evolved”, given the apparent age of the universe, and assuming technological progress must on average increase, then where are all the aliens? We appear to be alone. The “paradox” shares the same premises as the Drake, all of which combined say that development is inevitable.
The one obvious answer is to Fermi that we are alone is usually rejected. Not on logical grounds, but aesthetic.
The Drake and Fermi are not flawed logically: one can put probabilities to any question. But they are largely circular, since the goal of most who use them to is justify their pre-existing beliefs.
source wmbriggs.substack.com
JFK
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Oh, we know…
We know…
That probability is zero.
Not 10^(-100000000000), but exactly 0.
And this is the best proof for me that all those people at NASA and elsewhere, supporting the inevitability of alien life elsewhere are complete morons that have nothing to do with science.
The probability of life (any life, from the most basic forms to the most complex ones) getting extinct in our universe, far exceeds by immense orders of magnitude the probability of an existing life-form gaining a single advantageous mutation/trait that it didn’t have in the past.
Mother nature is a killer. And a very ruthless and efficient one…
Nice article BTW… 😉
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Howdy
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“then where are all the aliens? We appear to be alone. ”
As if you can draw conclusions on existent life in the whole universe based on an equation. Only science founded on this tiny speck of a planet, with a vanishingly small understanding of the cosmos is so presumptuous and self serving.
So why would any other race bother with such a species as Humans. Perhaps a bit of humility would help?
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ecm
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The equation, “I do not want to accept there are other species as intelligent as us”, is far stronger than Drake’s equation. Just ignore all the photos and credible eyewitness please–easy as “safe and effective” mRNA’s.
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very old white guy
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The words, show me, always come to mind when the talk turns to aliens.
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JFK
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Oh, there are MANY species more intelligent than us.
Especially nowadays, that most people are brain-dead.
The point is that none of them came into existence via some magic “evolution”, nor do they live in some far-away planet. And they are definitely not aliens of any sort.
The sightings (and not only sightings…) are things that have been with us for too long.
It is nothing new and, if you want my opinion, we should not focus on them so much.
It is clear they are not here to interfere with us yet (and thank God for that…), and we should respect that. And when they do, I suggest you start to panic…
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JFK
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OK, I should take that back and say “they are not here to interfere directly with us yet”. Because they have been screwing our lives indirectly for ever. And I can’t imagine what direct involvement would do to us…
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JFK
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And also, BTW, most sightings today are human creations.
And they don’t belong to a government.
But they definitely belong to the shadow government and some technocratic elites that will soon take over the entire world.
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Seriously
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I’m not completely sure but I just may be an alien…I mean, seriously, some of the crazy crap the human race does just boggles my mind!!! Throughout history! I frequently feel like that guy that can see the emperor isn’t wearing any clothes….and I’m the only one… though i do find some cool minds on here from time to time.
Don’t worry, I have no intention of interfering…too busy laughing my ass off or screaming out loud at the shear stupidity of the clown show…👽
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JFK
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As with any show, there will a time it ends.
And it will then become apparent that, none of those things you mention really mattered.
Not the emperor, not the clothes, not the laughter, not the tears, not the entire set itself.
Only what remains after the show is over, is what really matters.
And that is why we are here to begin with.
For a little while. 😉