If life on earth was a one in a billion chance, the human consciousness is further less probable. For the very reason human consciousness intrigues me like no other thing. We humans have emotions, we know how to express them, we can observe other person’s body signs and we can comprehend – we can do it all. All this sounds great and is great in fact, still the question stands tall. How did we develop this consciousness?
Consider abandoning a new born child on an island with chimps. If the child manages to survive, would it be any different than chimps? We were chimps too, at a certain point we were. Chimps have 24 pairs of chromosomes; we have one less i.e. 23. We share 99 % DNA with chimps and resemble very much in all the physical characteristics.
We are a species that literally broke through and came out of the blue. It is assumed that 2 pairs of chimps' chromosomes combined to form a single one and we humans began our journey in this giant gutter of outer-space (that is what rust from true detective thinks about earth).
Even though chimps are the closest thing to humans on the planet, yet the child (abandoned in the second paragraph) will never be able to develop a consciousness of human level. The reason behind this is that our full consciousness depends heavily on a tutor, who was tutored by another tutor.
The only sensible explanation for our fully developed consciousness could be that evolving humans somehow managed to record their observations over millenniums and passed them on with some medium to their successors. In more recent history (last 5000 years or so), there have been these inscriptions on walls that did the trick of conveying observations and imparting useful information to upcoming generations. Successors benefited from their predecessors' knowledge and eventually built upon that, generation by generation. Our ancestors must have done a tremendous job.
But, explanations are derivative and are inclined towards the already known facts. We have the explanation with us, but might never know about that breakthrough.
Probably, it went miraculously this way (let me rhyme a poem here):
That one dark night when the monkey died
Little ones mourned and turned away
A soul rested, a seed of consciousness sprouted
In-between this abyss they found a way...
Even if humanity manages to find life outside earth in this life cycle( everything grows, decays and eventually dies, this process repeats itself all the time- the cycle), it is safe to assume that a conscious life is nearly impossible to find (forget aliens invading earth already, for they might always remain “algae” on "john doe" planet and nothing more).