It is a fascinating mind bender...
the basics roughly follow this outline (from a great article at www.waitbutwhy.com):
1) Given the number of stars and
the different types of stars, scientists estimate there might be 500 billion
billion stars like our sun. That's right 500 billion billion which is
quite a few.
2) With a few more calculations we could arrive at an estimated
number of 100 billion billion earth-like planets. Given this crazy huge number
and given the age of the universe there should be some civilizations advanced
enough to communicate with us or at least be noticed by our scientists.
A type one civilization is one that has the power to harness the power of their own planet. We, the classification posits, are nearing this point. Humanity in its present state has achieved the ability to affect the whole planet. That is certain. We have destroyed vast forests, mined enormous quantities of minerals and oil. We have nearly depleted many of the world’s fisheries. We have built cities, damned rivers, and launched rockets and probes beyond the earth. We created and even used nuclear weapons that have the power to destroy the earth several times over. Yes my friends, our current technology allows us to affect and even destroy the entire earth and all of its ecosystems. We are pushing countless species to the brink of extinction and have already sent many others to the human engineered oblivion we seek to escape.
At our current state of development, we have a limited understanding of the cumulative effect of human population amplified by our technology on the systems of our planet. In today’s world, we are a great distance from creating methods to govern the outsized effects our species has on the planet. Even now, we all too easily dismiss the effect of individual action regarding our planet and even dismiss the actions of whole countries to try to alleviate some of the damage we are doing to our planet. We are nowhere near achieving coordinated action taken on behalf of all of humanity. We do not yet understand the intricacy and complexity of the systems of our planet. We have not developed enough to be able to protect and sustain them. Dare I say our species has failed to learn to love the earth enough to devote sufficient energy to nurturing our home.
Let us create an equation with the following notations:
Let N be the ability of the Holocene age earth to maintain its
equilibrium in the face of shocks to its systems.
Let P be the population of man.
Let T be the technological level of human civilization.
Let p^T be the shock to earth’s system a given size human
population can produce with a given level of civilization.
Let K be the knowledge of the cause and effects of the human
produced shocks on the planet.
Let C be the ability to coordinate human action to control the
effects of human produced shocks.
So the ability of the earth to maintain its equilibrium could be
written as
∑ from the dawn of humanity to the present of
N + KCPT -PT
We know that the current maximum value of PT is
already greater than N. The human race can create a shock sufficiently great to
overwhelm the ability of earth’s systems to self-correct. If the sum of the
difference between our knowledgeable and coordinated action and the human
induced negative shocks to the system become large enough to overwhelm the
ability of the Holocene earth to maintain equilibrium we will destroy
ourselves.
The great filter represents minimum achievement for
science, psychology, spirituality, and politics to protect the future of
humanity. It represents our physical ability to heal or atone for all of the
damage we have done to our biosphere. Let's call this our particular human
psycho/terrestrial filter.
Let's assume in the billions of years that the earth has been in
existence our science's ability to "hear" or "see" alien
life might, with optimism, cover the last 400 years (if we date it from the
discovery of the first telescope in 1608). That is about 1 hundred thousandth
of a percent of the time the earth has existed. I would call that a
miniscule flash in the history of the earth. We have not had long to
"hear" or "see".
The real question is: how long will this window remain open?
Will we have another 400 years to discover alien life
or be contacted by it?
On our current course, I don't think we will have a100.
I believe we stand on the precipice of the great filter. It is a
dangerous time. We have the ability and knowledge to destroy without the
commensurate knowledge and ability to healt. As of right now, I think Agent
Smith in the Matrix summed up our current conundrum -
Agent Smith: "I'd like to share a
revelation that I've had during my time here. It came to me when I tried to
classify your species and I realized that you're not actually mammals. Every mammal
on this planet instinctively develops a natural equilibrium with the
surrounding environment but you humans do not. You move to an area and you
multiply and multiply until every natural resource is consumed and the only way
you can survive is to spread to another area. There is another organism on this
planet that follows the same pattern. Do you know what it is? A virus. Human
beings are a disease, a cancer of this planet."
Are we a virus?
No, we are a form of life with a conscience and an ability
to cooperate. How we develop these abilities will determine whether we pass
beyond the psycho-terrestrial filter or find ourselves inhabiting a planet
which can no longer bear our presence. Unfortunately, we know a virus isn't the
only life capable of destruction. Humanity has shown a great proclivity for
choosing destruction as a solution to almost any problem.
When we discover the means (likely a combination of
political, psychological, spiritual, and technical) to create an
equilibrium between our ability to harness and transform our planet and our
ability to maintain its biosphere that discovery will be the
greatest advance yet of humanity.
The knowledge of our earth and the ability to positively
coordinate our actions will be the vehicle that will carry us beyond the
psycho-terrestrial filter.
It will be the interplanetary dawn of which science
fiction dreams and of which dystopian nightmares despair. This
will be the light that allows us to see others in the universe and hear
their voices.
Ite missa est.
Go it is the dismissal.