Great Filter: Why We’ve Never Discovered Signs Of Alien Life

Written by Luke McKinney

2001_8_3 The Great Filter is the idea that there is some single, almost insurmountably improbable barrier on the path to the stars that explains why we’ve never seen any sign of alien life. It combines aspects of astrology, biology and history to arrive at one inescapable conclusion: university professors dream of book deals.

Robin Hanson of George Mason University posits a “Great Filter” that prevents the rise of intelligent, self-aware, technologically advanced, space-colonizing civilizations. The “filter” would be one or more improbable steps along the path that starts with the creation of a planet and ends with a race capable of colonizing the galaxy.

Somewhere between those two points, philosopher Nick Bostrom points out, “the Great Filter operates, and it must be powerful enough that even with all the billions of possible starting worlds on which life might evolve – all those rolls of the cosmic dice – one ends up with nothing: no aliens, no spacecraft, no signals, at least not in our neck of the woods.”

The very existence of life makes finding a four-leafed clover with winning lottery tickets for leaves look like a sure thing. Add the staggering improbability of our evolution from single cells and you end up with odds so vast they’ve driven the invention of everything from the Drake equation to an invisible sky-beard who seems unnecessarily preoccupied with what we do one day out of every seven. People who study this subject file all that under “Shit we already knew”, and were too busy actually working on the science to come up with a garbage buzzword phrase that would look really awesome in bold type on the cover of a hardback book (available now for $29.99!) Luckily Robin Hanson was ready to do that for them.

There isn’t actually a book yet, but the Great Filter “theory” is so clearly designed to be publisher-ready you can almost see the page numbering. It talks in grand terms about a vast threat facing humanity, and if it never seems to have any idea what that threat actually is, was or will be then who cares? Most of the ‘evidence’ is based on the scarcity of life in the cosmos in general and how that describes threats to Earth specifically, otherwise known as “Fundamental misunderstanding of statistics #1”. He goes on to talk around this ethereal menace and all the effects it could have on THE SURVIVAL OF EARTH, combining lots of different fields in compelling pop-science friendly chapters without ever coming up with an actual result.

Not that we’re claiming that Professor Hanson doesn’t understand all this; just that he’s made a tactical decision not to care. His real intentions are further revealed by the way he throws around “possibility of world-destroying physics experiments” (we’re assuming he’ll scribble “I’M TALKING ABOUT THE LARGE HADRON COLLIDER” on autographed copies). This is a great buzzword for catching media attention and popular sales, at the tiny price of sacrificing even the pretense of scientific validity. Everyone who’s even heard of the basic physics of the LHC knows these cataclysm quotes are garbage.

Bostrom, director of the awesomely titled Future of Humanity Institute at Oxford University, claims that the Great Filter poses an “Existential Risk”. That’s a perfect choice of words because he thinks it means a threat to our very existence, when it’s really a made-up Nietzschean problem for people who should be delighted but are determined to be miserable anyway. He confirms this assessment by telling us we should take any discovery of alien life as terrible news, as that would put this mysteriously unspecified Filtering Boogeyman in our future instead of the past.

Listen: if we discover life on Mars and you can honestly call that a bad thing, then it’s not just that you aren’t a scientist. We’re not even sure you could be described as human.

10 thoughts on “Great Filter: Why We’ve Never Discovered Signs Of Alien Life

  1. Marco McClean

    Earth makes a lot of radio signals. But the inverse square law makes all our radio fade down into the noise floor by the orbit of Saturn. Intelligent creatures on a planet of even the nearest star –like, what, 20,000 times as far away (that’s 400 million times farther down beneath the noise)– certainly wouldn’t detect our civilization by radio unless 1. our two civilizations were alive and intelligent at the same time and, 2. we blasted a signal directly at them constantly with a hugely powerful transmitter for long enough to overlap with their own interest in radio and, 3. they set up a giant dish or array of dishes and kept it all pointed at /us/ long enough to pick up our /here we are, are you there?/ greeting. Hundreds of millions of years might not do it. And that’s just for a close-by star. There’s your cosmic filter.

    And how intelligent are we, really? Half the people in the U.S. believe they’re being watched over by guardian angels, and at least as many attribute every very fortunate or unfortunate chance event to supernatural intervention in their lives. Look at how many millions of people buy lottery tickets. And the endless wars– over what, really? If we ever get through to aliens and give them a true idea of what we’re like… Put yourself in their place; would you answer?

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