This Oxford philosopher hopes humanity's search for extraterrestrial life "finds nothing"

In our search for life beyond our home planet, finding even a small sign that alien life exists would be considered one of the greatest moments in human history. But not everyone shares that excitement. Nick Bostrom, director of the Future of Humanity Institute at the University of Oxford, has argued that he hopes our search for life beyond Earth comes up empty.

In his paper, “Where Are They? Why I Hope the Search for Extraterrestrial Life Finds Nothing,” Bostrom explains the reasoning behind his view. He even wrote that he hopes "our Mars probes will discover nothing," adding that "dead rocks and lifeless sands would lift my spirit." So why would an Oxford philosopher root against one of science's biggest dreams? Read on to find out.

With around 100 billion stars in our galaxy and countless Earth-like planets among them, intelligent life should, statistically, be everywhere. But Bostrom points out that "humans have, to date, seen no sign of any extraterrestrial intelligent civilization." From this, he concludes that "there exists a Great Filter," which he describes as a probability barrier.

In his paper, he noted, “You start with billions and billions of potential germination points for life, and you end up with a sum total of zero extraterrestrial civilizations that we can observe. The Great Filter must therefore be powerful enough – which is to say, the critical steps must be improbable enough – that even with many billions rolls of the dice, one ends up with nothing: no aliens, no spacecraft, no signals, at least none that we can detect in our neck of the woods.”

The origin of life itself is a strong sign, since "no instance of abiogenesis has ever been observed" even with many lab attempts to recreate it. Bostrom also noted that it took 1.8 billion years for simple cells to evolve into more complex ones with a nucleus, a transition that, as far as we know, only happened once. 

If that step really is the rare one, it would mean the Great Filter is behind us, and “we are most likely the only such civilization in our galaxy or even in the entire observable universe.”

There’s another possibility. It might be that the civilizations that reach the stage of development we have made so far are destroyed by “something,” even before they can spread through the galaxy. Bostrom lists threats like nuclear war and "superintelligent general artificial intelligence with destructive goals" as candidates. 

But for any of these to be the actual Great Filter, it would need to be something that nearly every advanced civilization eventually faces with disastrous consequences almost every time.

He explains that if we found simple life on Mars, "it would show that the Great Filter must exist somewhere after that period in evolution." And if the fossils looked more advanced, "we would have to conclude that the probability is very great that the bulk of the Great Filter is ahead of us." 

The more complex the life we find, the more it means that our hardest test, as humanity, is still ahead. If we find nothing, this would mean the Great Filter sits in our past. Bostrom says this is why he believes "that the silence of the night sky is golden."