We choose to search for extraterrestrial life and intelligence because as Americans, we are free, permissive, non-conformist, incorrigible, and preoccupied with our choices.
Searching for intelligence is like looking in the mirror and asking ourselves, where did we go wrong? The need for a messiah? Searching for life is like looking out the rear view of a bus and asking ourselves, how did we get here?
But dare we ask the question why did we get here? Brother Guy Consolmagno says the Bible is about the Creator and science is about the creation. In this context, science cannot answer why, it can only answer how. Religion does not answer how, but it can answer why even though we may not like the answer.
Utilizing Earth as a guide, life took 3.5 billion years to evolve, complex life 3 billion years, modern humans, the civilization-potential intelligent life (CPIL), about 100,000 years, and 10,000 to become a sophisticated intelligent civilization (SIC). Assuming a continuous life starting process somewhere in the Universe, a life bearing planet has a probability of exhibiting complex life of 86%, a civilization-potential intelligent life (CPIL) of 0.003% and sophisticated intelligent civilization (SIC) of 0.0003%, respectively.
But there is a gap.
William Borucki, Kepler mission principal investigator articulates, there are 300 billion stars in our Milky Way. Of that, 10% or 30 billion have planet(s). Of that, 10% or 3 billion have planet(s) in a life hospitable zone. The gap is, what proportion of these 3 billion stars with life hospitable planet(s) are life bearing? Or what is the hospitable-bearing probability? For example, assuming this number is 1% gives 30,000,000 life bearing stars, 900 CPIL and 90 SIC stars with planets like ours.
Classifying civilizations like ours as electromagnetic spectrum sophisticated civilizations (ESSC), a subset of sophisticated intelligent civilizations (SIC), we can estimate from Fermi's Paradox (where is everybody?) the hospitable-bearing probability. In our Milky Way, the upper bound of an ESSC is 1 per galaxy, as in spite of our electromagnetic spectrum sophistication, we have not heard from the others. That means the hospitable-bearing probability, that a life hospitable star is life bearing, is upper bounded by 0.01%. (Assumes ESSC and SIC probabilities are similar.) Sounds depressing?
As there are about 10^11 galaxies in our Universe, our figures gives us approximately 1 ESSC per galaxy or 10^11 such civilizations. We should be overwhelmed by intelligent signals, and SETI, the search for extraterrestrial life, should be successful. So where is everybody? It could just be that we are unable hear them because our detectors are not sensitive enough.
But there is another reason.
Bailey and Borwein graciously compiled from various scientists, seven reasons why we have not heard from anyone. (1) Contact is prohibited. (2) Too far away. (3) They lost interest. (4) Don't recognize their signals. (5) They self-destruct. (6) Long lived biological regime is rear. (7) We are alone.
Let's deconstruct. Point (7) we are alone in this galaxy, would concur with the hospitable-bearing probability of 0.01%, which is inclusive of (5) self-destruction and (6) that biological regimes are short lived, because silence is what we observe. We have to qualify that long lived biological regimes are ESSCs as, if we haven't heard from them we assume that they have self-destructed.
The remaining reasons are either improbable or incorrect. (1) is improbable as any civilization at least as advanced as ours would be as incorrigible as us Americans; free, permissive, and non-conformist because ground breaking innovations happen in spite of the status quo. (2) is incorrect as it assumes legacy physics that we cannot arrive sooner than the time allowed by the velocity of light. The new physics points to the possibility of interstellar travel, as a physics of destination arrival as opposed to destination travel. (3) is improbable. Is it possible all 10^11 SICs have lost interest in us? No. (4) is incorrect as the electromagnetic spectrum is the same anywhere in this Universe. The only difference between SICs would be the algorithms applied to their signals, if that. We would recognize an unnatural signal when presented, but none have.
From the perspective of logical completeness, two more reasons need to be included. (8) We are unable to recognize or choose to ignore the evidence, labeling the evidence as swamp gas, hysteria, etc. and (9) There is a new physics.
In "The Feasibility of Interstellar Propulsion" I made a very strong case for the new physics, and explained why legacy physics, Relativity, String & Quantum (RSQ) theories, have major problems. New physics can deliver interstellar propulsion, while legacy physics cannot.
As an example of the new physics, conservation of energy within a photon requires the existence of subspace. The photon's electromagnetic wave consists of both electric and magnetic fields whose amplitudes oscillate between 0% and +/-100%. Which begs the question, where do these fields go at less than 100% amplitude? Legacy physics does not ask this question. The new physics answer is that these oscillating fields transfer energy between spacetime and subspace.
Therefore, civilizations more advanced than ours are electromagnetically silent as their communications are buried in subspace. This reverses the hospitable-bearing probability of 0.01%, from upper bound to lower bound.
Given these probabilities the only viable conclusion is that (1) these SICs are not yet ESSCs or (2) when ESSCs discover the new physics, they evolve into electromagnetically silent civilizations (ESC) and therefore have appeared to self-destruct. The same symptom from different causes. The ESSC is short lived but not self-destructing, migrating quickly from electromagnetic spectrum sophistication to subspace technologies, and thus, the silence.
To estimate the number of ESSCs remaining, history shows that it took us about 150 years to become ESSC. We can assume based on exponential change, that in another 100 years we will become ESC. Assuming that sophisticated civilizations started randomly at about 1,000,000 years ago, then the number of existing ESSCs is 15,000,000. And if 1,000,000,000 years ago, it would be 15,000. The lower bound, assuming that life began a billion years after the big bang, is that our Universe has at least 1,200 ESSCs.
Of course the visible spectrum will not go silent as it is required for vision (Abraham Loeb and Edwin Turner); suggesting that the best SETI strategy is to search for the city lights of SIC/ESSC/ESC planets or look for bright spots, away from their stars, of what should be the dark side of these planets.
Therefore, the question, do we have the political will to prove that these civilizations exists?