The Great Filter

According to the Drake equation (formulated in 1961) there should be at least 50,000,000 intelligent technological civilisations in our Milky Way galaxy. More recent calculations, based on modern cosmological observations, give a more conservative estimate of 15,600,000 civilisations. Regardless, the theory and the mathematics predict substantial numbers of planets, within our own galaxy, supporting advanced technological life. Through the SETI program, vast resources have been spent in trying to identify intelligent life in the universe but so far to no avail. I have discussed this topic before in a post titled: ‘Where are the Little Green Men’. You might want to acquaint yourselves with the discussion engendered there before continuing with this post. In this post, I would like to concentrate on one specific issue: ‘The Great Filter’.

The ‘Great Filter’ idea was first proposed, not by a scientist, but the economist, Robin Hanson, in 1996. His thesis is an attempt to address the Fermi paradox. The Fermi paradox deals with the apparent contradiction regarding the high probability of advanced life in the universe and the total lack of evidence for said life. Hanson's proposal states that developing life, simple and intelligent, is subject to a series of sequential barriers that need to be overcome for future development. Failure to pass through these ‘barriers’ is likely to lead to extinction. A series of barriers, or filters, would be expected to decrease the number of potential civilisations present in the universe. Could it be that these filters have removed all advanced life forms except, one, that is us? Perhaps our civilisation hasn’t reached the critical event yet and the potential for extinction is still to come. Hanson proposes nine possibilities that must be fulfilled for intelligent life to evolve and advance to the ultimate attainment of interstellar travel:

The right star system

Formation of RNA and DNA molecules

Evolution of simple single cells (prokaryotes)

Evolution of complex single cells (eukaryotes)

Evolution of sexual reproduction

Complex, multi-cellular organisms

Tool using intelligent organisms

The technological stage that exists now

Colonisation of the galaxy/universe

This list should not be considered exhaustive and there may be other important and salient factors influencing the developmental process. The big question: has our civilisation passed the block or is the catastrophe still to come? Hanson thinks that the filter lies ahead. Thus, in his opinion, there is a barrier, in the future, that will, or may, prevent further progress. Several candidates are waiting to extinguish our existence: mayhap an asteroid will strike and wipe out all civilisation; there is the possibility that a supervolcano will erupt spreading ash, doom, and destruction upon our upturned and soot begrimed faces. These possibilities are considered rare contenders for our demise. There are more likely candidates: nuclear armageddon. A war between the super-powers could result in nuclear escalation ending in the total annihilation of civilisation; there is a possibility that Earth's resources will become exhausted. This may not necessarily lead to the total destruction of humanity, but it might push us back to a pre-technological status. A status from which it may prove difficult for us to return to our current technological advancement; there is a real possibility of a viral pandemic. Consider the humble flu virus. In 1918 a particularly virulent strain of influenza afflicted half of the human population resulting in a hundred million deaths. Given the rapid mutation rate of viruses, a future pandemic is a virtual certainty. However, it is difficult to gauge the impact this will have on our civilisation; there is a particularly chilling option. Our ability to create machines with artificial intelligence has become a reality and we continue to make vast strides in the arena of artificial intelligence. Perhaps, soon, we will develop machines that will think and act independently of their masters; machines endowed with a self-learning intellect immeasurably superior to our own. If we are unable to control our Frankenstein monster then we may find that the human race is deemed an impediment to our former robotic slaves. What happens when the human race finds itself redundant? These are just a few possible 'filter' scenarios. I'm sure my readers could think of others- let me know in the comments.     

Let us strive for optimism and imagine the following: by some means, somehow, we gather enough wisdom and knowledge to break through the remaining barrier. What awaits humanity on the other side? Assuming that technology continues to increase at the current rate we may expect to see colonisation, in the relatively near future, of our solar system beginning with the moon, and then perhaps, Mars. Obviously, the greatest barrier to interstellar travel is the vast distances entailed. Even travel to the nearest star, travelling at the speed of light, would take over four years. It is worth noting that we are denied the possibility of reaching light speed and even significant sub-light speeds by the fundamental laws of physics and ultimate universal reality. Some physicists believe that we can overcome this limitation by developing the warp drive. In this way, we could travel almost instantaneously between vast cosmic distances. However, warping spacetime comes with a hefty price. Indeed, the energy requirements are truly staggering and are unlikely to be attained by current technology. Therefore, it will be necessary to develop a system with manageable and feasible energy requirements. If mastered, the warp drive would allow for the rapid colonisation of other star systems. 

Hanson is a pessimist (ever met an optimistic economist?) and considers that the forthcoming 'Great Filter' represents a fundamental challenge for our species. If he is right this could explain why we see no evidence for other advanced civilisations, because there are none and we are all alone in a cold, uncaring universe. Could it be that we are special, very special (the snowflakes were right all along), and in the next million years or so we will become the masters of the galaxy?  What will we do if we encounter an emerging civilisation technologically less advanced than our own? Will we nurture that civilisation and provide succour? Or will we crush it underfoot and discard its broken remnants amongst the stars? Personally, I would like to see them burn. But, I would say that, wouldn't I?

There goes the alien neighbourhood